subject:(Benguela low level coastal jet)

Texas A&M University

1. Li, Pin. Quantifying the Contribution of Mean Flow and Eddy Advection to the Warm SST Bias in the Southeast Tropical Atlantic Region.

Degree: PhD, Oceanography, 2018, Texas A&M University

URL: http://hdl.handle.net/1969.1/174045

► In current-generation climate models, the warm sea surface temperature (SST) bias problem is most commonly seen in the eastern boundary upwelling systems (EBUSs), and is… (more)

▼ In current-generation climate models, the warm sea surface temperature (SST) bias problem is most commonly seen in the eastern boundary upwelling systems (EBUSs), and is most pronounced and most prevalent in the Southeast Tropical Atlantic (SETA) region. Previous studies have shown that the coastal wind pattern in this region, namely the Benguela low-level coastal jet (BLLCJ), is of great importance for the generation of such SST bias, because the coastal ocean circulation is highly sensitive to the off-shore structure of the wind forcing. Using an eddy-resolving regional ocean model, we first show that the SST bias in the region is drastically reduced when forced with simulated winds from a high-resolution regional atmospheric model. We subsequently demonstrate that the SST bias is highly sensitive to the spatial structure of the wind stress curl (WSC). We also find that when the ocean model is forced by a realistic high-resolution wind, the ocean model resolution is of second order importance in reducing the SST bias. Furthermore, we use a double-time average (DTA) method to quantify the contribution of heat budget terms, and show that the horizontal advection contributes significantly to the SST bias. We then examined the question: To what extent do ocean eddies play a role in balancing the coastal ocean heat budget and affecting the SST bias? By experimenting with a submesoscale eddy-permitting regional ocean model, we show that ocean eddies in the Southeast Tropical Atlantic region are most energetic near the Angola-Benguela Front (ABF), the Lüderitz Upwelling Cell region and the Agulhas Leakage region. In these three regions, comparisons between the two model simulations forced with the low- vs high-resolution winds suggest that the SST bias is mainly generated by mean flow advection with ocean eddies playing the role of counteracting the warming induced by the mean flow advection in this region. Advisors/Committee Members: Chang, Ping (advisor), Lin, Xiaopei (committee member), Hetland, Robert (committee member), Stössel, Achim (committee member), Saravanan, Ramalingam (committee member).

Subjects/Keywords: Climate model; SST bias; southeast tropical Atlantic; Benguela low-level coastal jet; Angola Current; Benguela Current; upwelling; eddy advection

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APA (6^th Edition):

Li, P. (2018). Quantifying the Contribution of Mean Flow and Eddy Advection to the Warm SST Bias in the Southeast Tropical Atlantic Region. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/174045

Chicago Manual of Style (16^th Edition):

Li, Pin. “Quantifying the Contribution of Mean Flow and Eddy Advection to the Warm SST Bias in the Southeast Tropical Atlantic Region.” 2018. Doctoral Dissertation, Texas A&M University. Accessed January 18, 2021. http://hdl.handle.net/1969.1/174045.

MLA Handbook (7^th Edition):

Li, Pin. “Quantifying the Contribution of Mean Flow and Eddy Advection to the Warm SST Bias in the Southeast Tropical Atlantic Region.” 2018. Web. 18 Jan 2021.

Vancouver:

Li P. Quantifying the Contribution of Mean Flow and Eddy Advection to the Warm SST Bias in the Southeast Tropical Atlantic Region. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1969.1/174045.

Council of Science Editors:

Li P. Quantifying the Contribution of Mean Flow and Eddy Advection to the Warm SST Bias in the Southeast Tropical Atlantic Region. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/174045

University of Colorado

2. Valenzuela, Raul A. Terrain-Trapped Airflows and Orographic Precipitation Along the Coast of Northern California.

Degree: PhD, Atmospheric & Oceanic Sciences, 2016, University of Colorado

URL: https://scholar.colorado.edu/atoc_gradetds/65

► While several studies have documented kinematic and precipitation structures associated with orographic effects in large-scale mountains (e.g. altitudes > 1.0 km MSL), surveys on… (more)

▼ While several studies have documented kinematic and precipitation structures associated with orographic effects in large-scale mountains (e.g. altitudes > 1.0 km MSL), surveys on small-scale mountains are still relatively rare. Given their lower altitude, these mountain are usually exposed to rain (instead of snow) during the approaching of baroclinic waves and concomitant warm and cold fronts, thus they are prone to flash floods and hydrological disasters during heavy rain episodes. One factor that influence kinematic and precipitation structures over mountain ranges is associated with airflows induced by the terrain itself, such as during low-level blocking and gap flow episodes. Force balance make these airflows move relatively parallel and in close proximity to the terrain, thus they can be categorized as terrain-trapped airflows (TTAs). TTAs can cause the lifting of incoming synoptic airflows upstream the terrains foothills, initiating and enhancing precipitation well before it would be observed by upslope forcing over the terrain. TTAs and orographic precipitation forcing along the small-scale coastal mountains of northern California have been studied from a 1-dimensional perspective; yet, details of the TTAs 3-dimensional kinematic and precipitation structure, especially in the lowest 500-m MSL, has not being addressed. In this doctoral thesis I examine physical characteristics and impacts of TTAs on orographic precipitation along the coastal mountains of northern California using a 13-winter season dataset. Selected case studies are employed to document in detail 3-dimensional kinematic and precipitation structures associated with pre-cold-frontal low-level jets (LLJs) and TTAs. The main observational asset is a ground-based X-band dual-polarization scanning Doppler radar located at the coast. Results show that TTAs are normally present during winter time, although with variable duration and offshore extension. In average, they account for 20% and 10% of the long-term rainfall along the coast and over the coastal mountains, respectively. Doppler radar observations depict the lifting of LLJs offshore forced by TTAs, creating an area of enhanced precipitation about 20 km from the coast. Forcing of the TTA seems to be most commonly associated with gap flows coming from Petaluma Gap and, to a shorter extent, with low-level blocking. Advisors/Committee Members: David Kingsmill, Katja Friedrich, John Cassano, Matthias Steiner, Albin Gasiewski.

Subjects/Keywords: atmospheric river; coastal jet; low-level jet; orographic precipitation; terrain-trapped airflow; weather radar; Meteorology; Remote Sensing; Statistics and Probability

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Valenzuela, R. A. (2016). Terrain-Trapped Airflows and Orographic Precipitation Along the Coast of Northern California. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/atoc_gradetds/65

Chicago Manual of Style (16^th Edition):

Valenzuela, Raul A. “Terrain-Trapped Airflows and Orographic Precipitation Along the Coast of Northern California.” 2016. Doctoral Dissertation, University of Colorado. Accessed January 18, 2021. https://scholar.colorado.edu/atoc_gradetds/65.

MLA Handbook (7^th Edition):

Valenzuela, Raul A. “Terrain-Trapped Airflows and Orographic Precipitation Along the Coast of Northern California.” 2016. Web. 18 Jan 2021.

Vancouver:

Valenzuela RA. Terrain-Trapped Airflows and Orographic Precipitation Along the Coast of Northern California. [Internet] [Doctoral dissertation]. University of Colorado; 2016. [cited 2021 Jan 18]. Available from: https://scholar.colorado.edu/atoc_gradetds/65.

Council of Science Editors:

Valenzuela RA. Terrain-Trapped Airflows and Orographic Precipitation Along the Coast of Northern California. [Doctoral Dissertation]. University of Colorado; 2016. Available from: https://scholar.colorado.edu/atoc_gradetds/65

University of Oklahoma

3. Smith, Elizabeth. The Great Plains Nocturnal Low-Level Jet: Spatial and Temporal Evolution.

Degree: PhD, 2018, University of Oklahoma

URL: http://hdl.handle.net/11244/316232

► The nocturnal low-level jet (NLLJ) is a maximum in the vertical wind profile often occurring in the lowest 1-km of the atmosphere during the overnight… (more)

▼ The nocturnal low-level jet (NLLJ) is a maximum in the vertical wind profile often occurring in the lowest 1-km of the atmosphere during the overnight hours in the Great Plains of the United States. This wind maximum has many implications including wind energy impacts, aviation hazards, and convection and precipitation forecasting. In broad terms, this dissertation set out to expand the current understanding of the mechanisms that lead to the development of NLLJs in the Great Plains. Using high resolution observations and numerical simulations together, this dissertation documents, describes, and analyzes spatial and temporal characteristics of the Great Plains nocturnal low-level jet. The first part of the dissertation focuses on identifying the optimal configuration in which to run the Weather Research and Forecasting (WRF) model for NLLJ studies. Horizontal spacing finer than 4-km did not offer enough improvement to the resulting simulation to justify computational expense. Using finer vertical spacing did improve simulations of NLLJs. Sensitivity to planetary boundary layer parameterization scheme was generally small. Based on the conducted sensitivity tests, the optimal WRF model configuration for NLLJ studies was identified as based on a grid with 4-km horizontal spacing, 40-m vertical constant spacing, and employing the Quasi-Normal Scale Elimination planetary boundary layer parameterization scheme. Next, data were collected during three Plains Elevated Convection at Night (PECAN) field campaign NLLJ cases and used alongside optimally configured simulations to identify and describe the spatial and temporal characteristics of Great Plains NLLJs. This analysis showed that the NLLJ is heterogeneous with respect to depth, wind speed, and wind direction. Additionally, the spatially heterogeneous NLLJ was shown to be moving across the slope of the Great Plains through the night. As such, the spatial and temporal characteristics of the nocturnal low-level jet are inherently connected and should not be considered independently. This spatial-temporal evolution of the NLLJ has multiple implications for our understanding of local NLLJ features. The typical spatial and temporal evolution of the NLLJ was described using PECAN observed cases. A set of fourteen cases (including both PECAN and Lower Atmospheric Boundary Layer Experiment, LABLE, cases) were used to document and describe features of this evolution. Two buoyancy-related driving mechanisms were investigated to explain the spatial-temporal variability of the NLLJ. The consideration of this motion and spatial heterogeneity showed that sudden changes in the nocturnal boundary layer structure could be induced by the advection of spatial jet characteristics. Advisors/Committee Members: Klein, Petra (advisor), Fedorovich, Evgeni (advisor), Shapiro, Alan (committee member), Gibbs, Jeremy (committee member), Mullen, Kieran (committee member).

Subjects/Keywords: mesoscale model; meteorological observations; low level jet

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Smith, E. (2018). The Great Plains Nocturnal Low-Level Jet: Spatial and Temporal Evolution. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/316232

Chicago Manual of Style (16^th Edition):

Smith, Elizabeth. “The Great Plains Nocturnal Low-Level Jet: Spatial and Temporal Evolution.” 2018. Doctoral Dissertation, University of Oklahoma. Accessed January 18, 2021. http://hdl.handle.net/11244/316232.

MLA Handbook (7^th Edition):

Smith, Elizabeth. “The Great Plains Nocturnal Low-Level Jet: Spatial and Temporal Evolution.” 2018. Web. 18 Jan 2021.

Vancouver:

Smith E. The Great Plains Nocturnal Low-Level Jet: Spatial and Temporal Evolution. [Internet] [Doctoral dissertation]. University of Oklahoma; 2018. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/11244/316232.

Council of Science Editors:

Smith E. The Great Plains Nocturnal Low-Level Jet: Spatial and Temporal Evolution. [Doctoral Dissertation]. University of Oklahoma; 2018. Available from: http://hdl.handle.net/11244/316232

University of Maryland

4. Rabenhorst, Scott Daniel. FIELD OBSERVATIONS AND MODEL SIMULATIONS OF LOW-LEVEL FLOWS OVER THE MID-ATLANTIC DURING AUGUST 1-5, 2006.

Degree: Atmospheric and Oceanic Sciences, 2012, University of Maryland

URL: http://hdl.handle.net/1903/13824

► For years, basic mountain, sea breeze, and low-level jet (LLJ) circulations have been studied, usually in locations with a high frequency of occurrence, sharp gradients,… (more)

▼ For years, basic mountain, sea breeze, and low-level jet (LLJ) circulations have been studied, usually in locations with a high frequency of occurrence, sharp gradients, or significant geographic prominence. However, there is evidence that similar circulations exist in non-classic locations with more mild topography and atmospheric gradients. One such understudied area is the U.S. Mid-Atlantic region. The Water Vapor Variability - Satellite/Sondes (WAVES) 2006 field campaign provided a contiguous 5-day period of concentrated high resolution observations to examine fine-scale details of a weather pattern typical of the Mid-Atlantic summertime. These measurements presented an opportunity for an intensive modeling study to further investigate peculiar phenomena with verification against research-grade observations. The observations captured two significant events: an official LLJ and a cold front with a prefrontal trough. A pronounced diurnal cycle was revealed which can be categorized into three stages: (1) daytime growth of the planetary boundary layer (PBL), (2) flow intensification into a LLJ regime after dusk, and (3) interruption by downslope winds (DW) after midnight. The third stage is most interesting owing to the lack of literature documenting similar occurrences in the Mid-Atlantic, which can impact air quality forecasting. Prior to high resolution modeling of the case study, sensitivity studies were conducted examining four areas to which the model was believed most sensitive: (1) initial condition data, (2) cumulus schemes, (3) PBL parameterizations, and (4) initialization times. Results also revealed shortcomings in model precipitation and PBL profiles, model biases, urban anomalies, and tendencies for forecast convergence. High resolution regional modeling showed the evolution of these nocturnal events and were verified against WAVES observations. A hybrid solenoidal influenced afternoon and early evening circulation east of the mountains. Afternoon deepening of a lee trough by an oscillating warm air band influenced low-level wind fields. Wind flow was further influenced by the thermal wind that originated over sloping terrain. Airflow traversed the Appalachian barrier and moved down the east flank of the Appalachians with katabatic and hydraulic contributions. This DW swept the LLJ regime off to the southeast. The prefrontal LLJ outflow in the Midwest strengthened DW events as the cold front approached. Advisors/Committee Members: Zhang, Da-Lin (advisor).

Subjects/Keywords: Atmospheric sciences; downslope winds; low level flows; low level jet; midatlantic; nocturnal flows; waves 2006

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APA (6^th Edition):

Rabenhorst, S. D. (2012). FIELD OBSERVATIONS AND MODEL SIMULATIONS OF LOW-LEVEL FLOWS OVER THE MID-ATLANTIC DURING AUGUST 1-5, 2006. (Thesis). University of Maryland. Retrieved from http://hdl.handle.net/1903/13824

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Rabenhorst, Scott Daniel. “FIELD OBSERVATIONS AND MODEL SIMULATIONS OF LOW-LEVEL FLOWS OVER THE MID-ATLANTIC DURING AUGUST 1-5, 2006.” 2012. Thesis, University of Maryland. Accessed January 18, 2021. http://hdl.handle.net/1903/13824.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Rabenhorst, Scott Daniel. “FIELD OBSERVATIONS AND MODEL SIMULATIONS OF LOW-LEVEL FLOWS OVER THE MID-ATLANTIC DURING AUGUST 1-5, 2006.” 2012. Web. 18 Jan 2021.

Vancouver:

Rabenhorst SD. FIELD OBSERVATIONS AND MODEL SIMULATIONS OF LOW-LEVEL FLOWS OVER THE MID-ATLANTIC DURING AUGUST 1-5, 2006. [Internet] [Thesis]. University of Maryland; 2012. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1903/13824.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rabenhorst SD. FIELD OBSERVATIONS AND MODEL SIMULATIONS OF LOW-LEVEL FLOWS OVER THE MID-ATLANTIC DURING AUGUST 1-5, 2006. [Thesis]. University of Maryland; 2012. Available from: http://hdl.handle.net/1903/13824

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

5. Adebiyi, Adeyemi A. The Impact of Meteorology on Smoke and Low-level Clouds over the Southeast Atlantic.

Degree: PhD, Meteorology and Physical Oceanography (Marine), 2016, University of Miami

URL: https://scholarlyrepository.miami.edu/oa_dissertations/1703

► In this dissertation, we use radiosondes and satellite observation, reanalysis datasets, as well as radiative and trajectory models to document the relationship between the low-level… (more)

▼ In this dissertation, we use radiosondes and satellite observation, reanalysis datasets, as well as radiative and trajectory models to document the relationship between the low-level clouds, smoke and meteorology over the southeast Atlantic. The southeast Atlantic presents a natural environment with one of the world’s largest marine low-level clouds, occurring along with the largest consumption of biomass fire over the adjacent southern African continent. This combination results in an extensive region of above-cloud biomass burning aerosols (predominantly smoke) over the marine low-level clouds, whereby the elevated smoke could lead to the stabilization of the lower troposphere, reduction of the cloud-top entrainment, and the build-up of water vapor within the boundary layer, which may eventually lead to increases in cloud fraction and decreases in cloud-top heights, in a process called semi-direct aerosol effect. The smokes are transported at a preferred altitude (∼750hPa – 550hPa) by a background easterly winds between July and October. During the same period, strong surface winds and ocean-influenced cold surface temperature characterize the meteorology within the boundary layer. The marine low-level cloud region is also associated with strong climatological subsidence above it, and cloud-top temperature inversion layer. The meteorological variations occurring above and below the low-level clouds are capable of influencing the cloud properties, and therefore may confound with the aerosol effects, making the separation of the aerosol and meteorological influences, on the low-level cloud, a very difficult challenge. We address this problem by identifying the dynamical and thermodynamical variations above the low-level clouds during the the peak aerosol months (July–October). Specifically, three areas are explored in this dissertation: the convolution of the dynamical and moisture effects with shortwave-absorbing aerosols over the low-level clouds; the role of the mid-tropospheric easterly-transporting system on both the elevated smoke and the low-level cloud environments; and the synoptic-scale sensitivity of the low-level clouds to a range of interacting meteorological conditions, with and without the presence of the elevated smoke. First, the analysis of the radiosondes at St. Helena Island, a small island located approximately 1800 km offshore of continental Africa (15.9◦S, 5.6◦W), shows the presence of mid-tropospheric moisture within the smoke layer, and above the low-level clouds. The smoke layer has previously been associated with hot and dry layer, perhaps in analogy to the Saharan air layer. The mid-tropospheric moisture over the south-east Atlantic has not been previously documented, and it occurs more than 70% of the time between September and October. During the same months, as the aerosol loading increases, the amount of the mid-tropospheric moisture also increases. The result of the radiative transfer calculations shows that the mid-tropospheric moisture-induced longwave cooling accounts for about 30%… Advisors/Committee Members: Paquita Zuidema, Amy Clement, Brian Mapes, Chidong Zhang, Robert Wood.

Subjects/Keywords: Smoke; Aerosol; Low-level Cloud; Southern African Easterly Jet; Meteorology; Atlantic

12 more images…

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APA (6^th Edition):

Adebiyi, A. A. (2016). The Impact of Meteorology on Smoke and Low-level Clouds over the Southeast Atlantic. (Doctoral Dissertation). University of Miami. Retrieved from https://scholarlyrepository.miami.edu/oa_dissertations/1703

Chicago Manual of Style (16^th Edition):

Adebiyi, Adeyemi A. “The Impact of Meteorology on Smoke and Low-level Clouds over the Southeast Atlantic.” 2016. Doctoral Dissertation, University of Miami. Accessed January 18, 2021. https://scholarlyrepository.miami.edu/oa_dissertations/1703.

MLA Handbook (7^th Edition):

Adebiyi, Adeyemi A. “The Impact of Meteorology on Smoke and Low-level Clouds over the Southeast Atlantic.” 2016. Web. 18 Jan 2021.

Vancouver:

Adebiyi AA. The Impact of Meteorology on Smoke and Low-level Clouds over the Southeast Atlantic. [Internet] [Doctoral dissertation]. University of Miami; 2016. [cited 2021 Jan 18]. Available from: https://scholarlyrepository.miami.edu/oa_dissertations/1703.

Council of Science Editors:

Adebiyi AA. The Impact of Meteorology on Smoke and Low-level Clouds over the Southeast Atlantic. [Doctoral Dissertation]. University of Miami; 2016. Available from: https://scholarlyrepository.miami.edu/oa_dissertations/1703

University of Oklahoma

6. Bonin, Timothy. Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes.

Degree: PhD, 2015, University of Oklahoma

URL: http://hdl.handle.net/11244/14623

► The intensity, extent, and continuity of turbulence in the nocturnal stable boundary layer (SBL) is governed by many interacting processes and features. Generally, SBLs can… (more)

▼ The intensity, extent, and continuity of turbulence in the nocturnal stable boundary layer (SBL) is governed by many interacting processes and features. Generally, SBLs can be grouped into two broad categories: weakly stable and very stable. While the weakly SBL is relatively well understood and can be described by Monin-Obukhov similarity theory or other local scaling laws, the very SBL is difficult to characterize and parameterize. It is also difficult to predict which type of SBL will form nocturnally as differentiating characteristics of the two regimes are not well-known. Furthermore, nocturnal low-level jets (LLJs) often form around sunset, particularly in the Great Plains region of the United States, and generally interact with the nocturnal SBL. These relationships between LLJs and the SBL are currently not well-understood. To characterize turbulence within the SBL, vertical velocity variances estimated from Doppler lidar (DL) observations are used, which first need to be validated. To accomplish this, DL-derived values of vertical velocity variance are directly compared with those from sonic anemometer observations installed on a 300-m tower during the Lower Atmospheric Thermodynamics and Turbulence Experiment (LATTE), which was conducted in February – April 2014 at the Boulder Atmospheric Observatory . An autocovariance method of removing noise from the DL observations is used, which is shown to improve measurements of vertical velocity variance. In addition to removing noise, this method can also correct for underestimates of variance due to time and volume averaging of the DL. Generally, the DL-derived variance values tend to agree closely with those from the sonic anemometers after the autocovariance correction is applied. To investigate the SBL in detail, Doppler lidar, sonic anemometer, Atmospheric Emitted Radiance Interferometer (AERI), and radiosonde measurements that were collected during the Lower Atmospheric Boundary Layer Experiment (LABLE-I) are analyzed. LABLE-I was a multi-institutional field campaign that took place from 18 September to 13 November 2012 at the Southern Great Plains site in north central Oklahoma. During the experiment, LLJs were frequently observed and interacted with both weakly and very stable SBLs. Within the weakly stable boundary layer, turbulence tended to be generated at the surface and transported upward, and no strong surface-based inversion formed overnight. When a strongly stable boundary layer formed, mixing was either generated near a LLJ or at the surface and remained very weak overnight. On these nights, a strong surface based inversion formed and slowly grew throughout the night. LLJs also evolved differently depending on if a weakly or strongly SBL formed. With a strongly SBL, LLJs tended to increase in both strength and height overnight, often corresponding to a gradual increase in synoptic-scale forcing. LLJs that occurred with a weakly SBL generally remained constant in height overnight, and reached a peak in strength around… Advisors/Committee Members: Klein, Petra (advisor), Chilson, Phillip (advisor), Shapiro, Alan (committee member), Turner, David (committee member), Miller, David (committee member).

Subjects/Keywords: Low-level jet; Stable boundary layer; Doppler lidar

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bonin, T. (2015). Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/14623

Chicago Manual of Style (16^th Edition):

Bonin, Timothy. “Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes.” 2015. Doctoral Dissertation, University of Oklahoma. Accessed January 18, 2021. http://hdl.handle.net/11244/14623.

MLA Handbook (7^th Edition):

Bonin, Timothy. “Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes.” 2015. Web. 18 Jan 2021.

Vancouver:

Bonin T. Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes. [Internet] [Doctoral dissertation]. University of Oklahoma; 2015. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/11244/14623.

Council of Science Editors:

Bonin T. Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes. [Doctoral Dissertation]. University of Oklahoma; 2015. Available from: http://hdl.handle.net/11244/14623

Iowa State University

7. Garberoglio, Michael. Sensitivity of boundary layer characteristics and related low-level jet behavior to planetary boundary layer schemes in the WRF for several MCS cases.

Degree: 2020, Iowa State University

URL: https://lib.dr.iastate.edu/etd/18129

► During the spring and summer months, convective precipitation is a common occurrence across the central United States. This frequent precipitation often comes in the form… (more)

▼ During the spring and summer months, convective precipitation is a common occurrence across the central United States. This frequent precipitation often comes in the form of mesoscale convective systems (MCSs), which provide a large amount of the necessary water to the agricultural industry of the region. MCSs, which require large amounts of moisture and wind shear to form, are often fueled in this region by the Great Plains Low-Level Jet (LLJ). These phenomena are responsible for a large majority of the moisture transport into the region and are a main ingredient in summer MCSs. While numerical weather prediction has improved greatly in recent years, accurate forecasting of the LLJ still remains a challenge. Therefore, a further understanding of LLJ simulation is needed to better predict MCSs. To understand how models can simulate the LLJ, atmospheric conditions with the planetary boundary layer (PBL) must be analyzed and understood within numerical models. Parameterization is important in representing small-scale processes and closing systems of dynamic equations, but model sensitivity to these parameterization schemes is something that has not been greatly explored. This work focuses on investigating how three different PBL schemes, the Mellor-Yamada-Janjic (MYJ) scheme, the Mellor–Yamada–Nakanishi–Niino (MYNN) scheme, and the Yonsei University (YSU) scheme, impact the simulation of the PBL and the impact those conditions have on LLJs. First, the Weather Research and Forecasting model was used to simulate 30 cases previously studied by Squitieri and Gallus (2016a,b), including 15 strongly-forced cases (Type C) and 15 weaker-forced cases (Type A). The behavior of the PBL and LLJ were analyzed for each case to determine the impacts different PBL scheme had on the model output. It was found that MYJ and MYNN had similar tendencies when simulating the afternoon PBL, but when simulating the LLJ, MYNN tended to be more of an outlier, especially when forecasting the location of the LLJ peak. YSU, being a nonlocal closure scheme compared to two local schemes, behaved differently from the other two schemes, more often simulating a dry and warm boundary layer compared to the other schemes as well as observations, which had impacts on the LLJ. Second, a modified version of the MYNN scheme, referred to hereafter as the mod-MYNN scheme, was compared to the original as well as observational data to see if modified physics were able to improve the forecast of the LLJ and subsequent MCSs. It was found that both schemes perform similarly to one another, but the modified scheme performed slightly more like a nonlocal scheme, displaying similar biases to those of YSU in the first part of the experiments, although both schemes fail to completely capture the MCSs and resulting nocturnal precipitation accurately.

Subjects/Keywords: Boundary Layer; Low-level jet; Meteorology; PBL; PBL Schemes

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APA (6^th Edition):

Garberoglio, M. (2020). Sensitivity of boundary layer characteristics and related low-level jet behavior to planetary boundary layer schemes in the WRF for several MCS cases. (Thesis). Iowa State University. Retrieved from https://lib.dr.iastate.edu/etd/18129

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Garberoglio, Michael. “Sensitivity of boundary layer characteristics and related low-level jet behavior to planetary boundary layer schemes in the WRF for several MCS cases.” 2020. Thesis, Iowa State University. Accessed January 18, 2021. https://lib.dr.iastate.edu/etd/18129.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Garberoglio, Michael. “Sensitivity of boundary layer characteristics and related low-level jet behavior to planetary boundary layer schemes in the WRF for several MCS cases.” 2020. Web. 18 Jan 2021.

Vancouver:

Garberoglio M. Sensitivity of boundary layer characteristics and related low-level jet behavior to planetary boundary layer schemes in the WRF for several MCS cases. [Internet] [Thesis]. Iowa State University; 2020. [cited 2021 Jan 18]. Available from: https://lib.dr.iastate.edu/etd/18129.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Garberoglio M. Sensitivity of boundary layer characteristics and related low-level jet behavior to planetary boundary layer schemes in the WRF for several MCS cases. [Thesis]. Iowa State University; 2020. Available from: https://lib.dr.iastate.edu/etd/18129

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Oklahoma

8. Reif, Dylan. Initiation Mechanisms of Nocturnal Convection Without Nearby Surface Boundaries Over the Great Plains.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/326655

► Nocturnal convection initiation accounts for nearly half of all CI events (daytime and nighttime) over the Great Plains over the warm season. There are three… (more)

▼ Nocturnal convection initiation accounts for nearly half of all CI events (daytime and nighttime) over the Great Plains over the warm season. There are three main types of CI events: those that occur on surface boundaries, those that occur on the cold side of surface boundaries, and those that occur with no nearby surface boundaries (NB [no boundary] CI mode). This study focuses on the poorly-understood NB nocturnal CI mode events. These storms typically occur in environments with weak forcing or occur far away from preexisting convection and away from surface boundaries. There are preferred characteristics to these events, however. For example, these events form later at night (around 0900 UTC), occur on the eastern side of the low-level jet (LLJ), and the linear systems tend to be oriented north/south. Three initiation mechanisms are explored here in detail: ascent due to atmospheric bores, ascent due to the nocturnal LLJ, and ascent associated with cyclonic potential vorticity (PV) anomalies. The gravity wave and LLJ mechanisms are explored using three-dimensional idealized numerical simulations, and PV inversion is used to explore the PV anomaly mechanism. A composite sounding was created based on 108 proximity soundings for NB CI mode events. Nine environments representing a range in winds and temperature are used to test each mechanism's effect on a range of nocturnal environments. In these simulations, the vertical velocity associated with atmospheric bores is between 0.5 and 1 m s-1, and the net displacement is 200 – 500 m. The vertical velocity associated with the LLJ is 1 cm s-1, but due to the sustained ascent throughout the night, the net displacements can be as much as 1 km. Finally, the ascent associated with PV anomalies is between 0.1 and 1 cm s-1, and the net displacement is typically between 50 and 100 m. Based on these displacements, gravity waves and the LLJ are likely CI mechanisms, while PV anomalies are not likely to cause CI. Advisors/Committee Members: Bluestein, Howard (advisor), Fulton, Caleb (committee member), Cavallo, Steven (committee member), Parsons, David (committee member), Shapiro, Alan (committee member).

Subjects/Keywords: Convection Initiation; Low-Level Jet; Potential Vorticity; Atmospheric Bores

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Reif, D. (2020). Initiation Mechanisms of Nocturnal Convection Without Nearby Surface Boundaries Over the Great Plains. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/326655

Chicago Manual of Style (16^th Edition):

Reif, Dylan. “Initiation Mechanisms of Nocturnal Convection Without Nearby Surface Boundaries Over the Great Plains.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed January 18, 2021. http://hdl.handle.net/11244/326655.

MLA Handbook (7^th Edition):

Reif, Dylan. “Initiation Mechanisms of Nocturnal Convection Without Nearby Surface Boundaries Over the Great Plains.” 2020. Web. 18 Jan 2021.

Vancouver:

Reif D. Initiation Mechanisms of Nocturnal Convection Without Nearby Surface Boundaries Over the Great Plains. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/11244/326655.

Council of Science Editors:

Reif D. Initiation Mechanisms of Nocturnal Convection Without Nearby Surface Boundaries Over the Great Plains. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/326655

Universidade do Rio Grande do Sul

9. Moraes, Flávia Dias de Souza. Ambiente atmosférico favorável ao desenvolvimento de complexos convectivos de mesoescala no sul do Brasil.

Degree: 2016, Universidade do Rio Grande do Sul

URL: http://hdl.handle.net/10183/139067

►

Complexos Convectivos de Mesoescala (CCM) são eventos meteorológicos de difícil previsão, que resultam em tempestades severas e desastres. O objetivo deste trabalho é indicar as… (more)

▼

Complexos Convectivos de Mesoescala (CCM) são eventos meteorológicos de difícil previsão, que resultam em tempestades severas e desastres. O objetivo deste trabalho é indicar as características em grande escala do ambiente atmosférico favorável para a formação de CCM no Sul do Brasil, entre 1998 e 2007. Fez-se uso da base de dados de CCM de Durkee e Mote (2009), assim como das variáveis de Potencial de Energia Convectiva Disponível (CAPE), ponto de orvalho, temperatura, altura geopotencial, componentes de vento u e v e umidade relativa da reanálise do National Center for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR), coletadas entre 2,5 e 5,5 horas antes do desenvolvimento dos CCM. Com o método de Análise das Componentes Principais (ACP), geraram-se as composições do ambiente atmosférico médio favorável ao desenvolvimento dos CCM, para comparar o grupo dos que ocorreram no Sul do Brasil ao dos que atuaram em outras regiões da AS. Usando como dado de entrada as variáveis de altura geopotencial e temperatura (em 850 hPa), foram encontradas quatro componentes principais para cada um dos grupos de CCM. Com base nas componentes principais, nas variáveis atmosféricas e nas cartas sinóticas, foram reconstruídos os ambientes atmosféricos médios para identificar o comportamento das características atmosféricas prévias aos CCM para cada conjunto de eventos. Os resultados identificaram 303 CCM, 96 no Sul do Brasil, 168 em outras regiões da AS e 39 oceânicos. O ambiente atmosférico médio dos 168 CCM não apresentou características homogêneas, pois 75% das componentes não possuíam jatos de baixos níveis (JBN) dentro dos critérios adotados, mas a presença de um escoamento meridional. Esse fluxo, ao encontrar com a região de divergência dos jatos de altos níveis (JAN), foi um dos fatores favoráveis para a convecção, já que seus valores de CAPE (≥ 450 J kg-1) eram menores que a média esperada para formação de tempestades e só uma das componentes teve frentes frias associadas. Por outro lado, o grupo dos 96 CCM que atuaram no Sul do Brasil mostrou-se cerca de 50.000 km² maior em extensão que os das outras regiões da AS e dos EUA e com duração de pelo menos 3 h a mais. Além disso, as características atmosféricas do grupo de CCM do Sul do Brasil mostraram padrões homogêneos, podendo indicar a formação de CCM nessa região quando: o campo de ventos médios em 850 e 200 hPa, se encontrarem em posição ortogonal, indicando acoplamento entre os jatos de baixos e altos níveis; os valores de CAPE forem ≥ 600 J kg-1 e o cisalhamento vertical estiver entre 7 e 12 m s-1; houver atuação das frentes frias no sul da AS; a umidade relativa disponível estiver concentrada próxima à região Sul do Brasil, com valores maiores que 80%; a altura geopotencial (850 hPa) apresentar um cavado na região gênese dos CCM e a temperatura (850 hPa) estiver mais elevada próxima e ao norte da região de formação.

Mesoscale Convective Complexes (MCCs) are meteorological events difficult to forecast, which result in severe storms and other…

Advisors/Committee Members: Aquino, Francisco Eliseu.

Subjects/Keywords: Convective systems; Complexos Convectivos de Mesoescala; Empirical orthogonal functions; América do Sul; CFSR; Low-level jet; Upper-level jet; South America

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Moraes, F. D. d. S. (2016). Ambiente atmosférico favorável ao desenvolvimento de complexos convectivos de mesoescala no sul do Brasil. (Thesis). Universidade do Rio Grande do Sul. Retrieved from http://hdl.handle.net/10183/139067

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Moraes, Flávia Dias de Souza. “Ambiente atmosférico favorável ao desenvolvimento de complexos convectivos de mesoescala no sul do Brasil.” 2016. Thesis, Universidade do Rio Grande do Sul. Accessed January 18, 2021. http://hdl.handle.net/10183/139067.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Moraes, Flávia Dias de Souza. “Ambiente atmosférico favorável ao desenvolvimento de complexos convectivos de mesoescala no sul do Brasil.” 2016. Web. 18 Jan 2021.

Vancouver:

Moraes FDdS. Ambiente atmosférico favorável ao desenvolvimento de complexos convectivos de mesoescala no sul do Brasil. [Internet] [Thesis]. Universidade do Rio Grande do Sul; 2016. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10183/139067.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Moraes FDdS. Ambiente atmosférico favorável ao desenvolvimento de complexos convectivos de mesoescala no sul do Brasil. [Thesis]. Universidade do Rio Grande do Sul; 2016. Available from: http://hdl.handle.net/10183/139067

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

10. Jimenez Sanchez, Jorge Giovanni. The Orinoco low-level jet.

Degree: 2018, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/15903jgj118

► The low-level jet over the Orinoco River basin is characterized using finer horizontal, vertical, and temporal resolution than possible in previous studies via dynamical downscaling.… (more)

▼ The low-level jet over the Orinoco River basin is characterized using finer horizontal, vertical, and temporal resolution than possible in previous studies via dynamical downscaling. The investigation relies on a 5-month-long simulation (November 2013- March 2014) performed with the Weather Research and Forecasting model, with initial and boundary conditions provided by the Global Forecast System analysis. Dynamical downscaling is demonstrated to be an effective method to better resolve the horizontal and vertical characteristics of the OLLJ, not only improving its diurnal and austral-summer evolution, the identification and location of low-level jet streaks inside the stream tube, but also in determining the mechanisms leading to its formation. The Orinoco low-level jet (OLLJ) is found to be a single stream tube over Colombia and Venezuela with wind speeds greater than 8 m s-1, and four distinctive cores varying in height under the influence of sloping terrain. The OLLJ has its maximum monthly mean wind speed (13 m s-1) and largest spatial extent (2100 km × 400 km) in January. The maxima mean wind speeds (13–17 m s-1) in the diurnal cycle occur in the early morning above the nocturnal inversion; wind speeds are a minimum (8–9 m s-1) in the late afternoon when a deep, approximately unstratified boundary layer is present. The momentum balance analysis performed in a streamwise- and crosswise-rotated coordinate system reveal that the OLLJ is the result of four phenomena acting together to accelerate the wind: a sea-breeze penetration over the Orinoco River delta and Unare River depression, katabatic flow down the Coastal Cordillera, three expansion fans from point wakes in topography, and diurnal variation of turbulent diffusivity. The latter, in contrast to the heavily studied nocturnal low-level jet in the U.S. Great Plains region, plays only a secondary role in OLLJ acceleration. These results suggest that LLJs near the equator may originate from processes other than the inertial oscillation and topographic thermal forcing. Advisors/Committee Members: Paul Markowski, Dissertation Advisor/Co-Advisor, Paul Markowski, Committee Chair/Co-Chair, George Spencer Young, Committee Member, David Jonathan Stensrud, Committee Member, Andrew Mark Carleton, Outside Member.

Subjects/Keywords: Low-level jet; Orinoco River; Llanos Savannas; Dynamical downscaling; WRF; Colombia; Venezuela; Momentum balance; sea breeze; Unare depression; Katabatic flow; Bora; gravity current; density current; downslope flow; expansion fan; point wakes; supercritical channel flow; turbulent diffusivity; Planetary Boundary Layer; PBL; Atmospheric Boundary Layer; ABL; LLJ; OLLJ; Blackadar mechanism; Holton mechanism; inertial oscillation; topographic thermal forcing; Orinoco low-level jet; Llanos low-level jet; Llanos; Tropics; Tropical meteorology; Mesoscale meteorology; bore; Guiana Highlands; Eastern Cordillera; Andes; Coastal Cordillera; Merida Cordillera; Guanipa Mesa; Macarena mountain range; Colombian Air Force; Fuerza Aerea Colombiana; low-level wind shear; aviation; boundary layer; Austral summer

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Jimenez Sanchez, J. G. (2018). The Orinoco low-level jet. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/15903jgj118

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Jimenez Sanchez, Jorge Giovanni. “The Orinoco low-level jet.” 2018. Thesis, Penn State University. Accessed January 18, 2021. https://submit-etda.libraries.psu.edu/catalog/15903jgj118.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Jimenez Sanchez, Jorge Giovanni. “The Orinoco low-level jet.” 2018. Web. 18 Jan 2021.

Vancouver:

Jimenez Sanchez JG. The Orinoco low-level jet. [Internet] [Thesis]. Penn State University; 2018. [cited 2021 Jan 18]. Available from: https://submit-etda.libraries.psu.edu/catalog/15903jgj118.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Jimenez Sanchez JG. The Orinoco low-level jet. [Thesis]. Penn State University; 2018. Available from: https://submit-etda.libraries.psu.edu/catalog/15903jgj118

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

11. Fisher, Andrew Michael. INCONSISTENCIES IN THE WEATHER RESEARCH AND FORECASTING MODEL OF THE MARINE BOUNDARY LAYER ALONG THE COAST OF CALIFORNIA.

Degree: MS, Atmospheric Science, 2017, University of Kansas

URL: http://hdl.handle.net/1808/25984

► The late spring and summer low-level wind field along the California coast is primarily controlled by the pressure gradient between the Pacific high and the… (more)

▼ The late spring and summer low-level wind field along the California coast is primarily controlled by the pressure gradient between the Pacific high and the thermal low over the desert southwest. Strong northwesterly winds within the marine boundary layer (MBL) are common and the flow is often described as a two-layer shallow water hydraulic system, capped above by subsidence and bounded laterally by high coastal topography. Hydraulic features such as an expansion fan can occur near major coastal headlands. Numerical simulations using the Weather Research and Forecasting (WRF) modeling system were conducted over a two-month period and compared to observations from several buoy stations and aircraft measurements from the Precision Atmospheric Marine Boundary Layer Experiment (PreAMBLE). Model performance of the atmospheric adjustment near the Point Arguello and Point Conception (PAPC) headlands and into the Santa Barbara Channel (SBC) is assessed. Substantial inconsistencies are revealed, especially in the SBC. The strength of the synoptic forcing impacts model performance upstream of PAPC. The model maintains stronger winds than observed under weak forcing regimes, inadequately representing periods of wind relaxation. The large-scale forcing has minimal impact on the flow in the SBC, where poor modeling of the MBL characteristics exists throughout the entire period. Similar results are found in the coarser North American Mesoscale (NAM) model. In general, WRF overestimates the wind speed around PAPC and the expansion fan extends too far into the SBC. Previous conceptual models were based on similar flawed model results and limited observations. PreAMBLE measurements reveal a more complex lower atmosphere in the SBC than the simulations can represent. Mischaracterization of surface wind stress in the SBC has implications for forcing ocean models with WRF. Understanding model biases of the vertical profile of temperature and humidity are also critical to several national defense agencies with interests in atmospheric refractivity conditions and its impact on their operations. Advisors/Committee Members: Rahn, David A (advisor), Mechem, David B (cmtemember), Braaten, David A (cmtemember).

Subjects/Keywords: Atmospheric sciences; Meteorology; Atmospheric Refractivity; California; Coastal Low-level Jet; Expansion Fan; Marine Boundary Layer; WRF

…1987; Lester 1985; Gerber et al. 1989; Parish 2000). The low-level jet (LLJ)… …conditions? Large-scale pressure features drive the coastal low-level dynamics and influence MBL… …contrast, the low-level flow near coastal station bpt is relatively strong and nearly entirely… …strong low-level horizontal pressure gradient force (PGF) between the Pacific high… …and thermal low drives the coastal wind. Subsidence associated with the subtropical branch…

10 more images…

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Fisher, A. M. (2017). INCONSISTENCIES IN THE WEATHER RESEARCH AND FORECASTING MODEL OF THE MARINE BOUNDARY LAYER ALONG THE COAST OF CALIFORNIA. (Masters Thesis). University of Kansas. Retrieved from http://hdl.handle.net/1808/25984

Chicago Manual of Style (16^th Edition):

Fisher, Andrew Michael. “INCONSISTENCIES IN THE WEATHER RESEARCH AND FORECASTING MODEL OF THE MARINE BOUNDARY LAYER ALONG THE COAST OF CALIFORNIA.” 2017. Masters Thesis, University of Kansas. Accessed January 18, 2021. http://hdl.handle.net/1808/25984.

MLA Handbook (7^th Edition):

Fisher, Andrew Michael. “INCONSISTENCIES IN THE WEATHER RESEARCH AND FORECASTING MODEL OF THE MARINE BOUNDARY LAYER ALONG THE COAST OF CALIFORNIA.” 2017. Web. 18 Jan 2021.

Vancouver:

Fisher AM. INCONSISTENCIES IN THE WEATHER RESEARCH AND FORECASTING MODEL OF THE MARINE BOUNDARY LAYER ALONG THE COAST OF CALIFORNIA. [Internet] [Masters thesis]. University of Kansas; 2017. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1808/25984.

Council of Science Editors:

Fisher AM. INCONSISTENCIES IN THE WEATHER RESEARCH AND FORECASTING MODEL OF THE MARINE BOUNDARY LAYER ALONG THE COAST OF CALIFORNIA. [Masters Thesis]. University of Kansas; 2017. Available from: http://hdl.handle.net/1808/25984

12. Alcântara, Clênia Rodrigues. Um estudo da relação entre jatos de baixos níveis e linhas de instabilidade da Amazônia.

Degree: PhD, Meteorologia, 2010, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/14/14133/tde-25062013-202138/ ;

►

O enfoque deste trabalho é contribuir para a compreensão dos processos que definem a propagação de linhas de instabilidade tropicais da Amazônia. Foi feita a… (more)

▼

O enfoque deste trabalho é contribuir para a compreensão dos processos que definem a propagação de linhas de instabilidade tropicais da Amazônia. Foi feita a análise de 9 anos de imagens de satélite definindo casos de linha de instabilidade e relacionando sua ocorrência com as do seu ambiente. Foi ressaltado o papel dos jatos de baixos níveis na propagação das linhas de instabilidade e verificadas possíveis diferenças entre os sistemas que se propagam e os que não se propagam. A partir da análise observacional foram feitas simulações numéricas com o modelo BRAMS para explorar a sensibilidade da propagação das linhas de instabilidade às características cinemáticas do ambiente. Como resultado principal, obteve-se que a maioria dos casos observados foi de linhas que não se propagaram, permanecendo quase estacionárias nas proximidades da costa norte do Brasil. Do total de casos de LI identificadas nas imagens de satélite, apenas 20% foram de linhas se propagaram mais de 400 km. O perfil do vento para seu ambiente de formação e desenvolvimento possui características que reúnem um jato em baixos níveis, um jato em altos níveis e pouco cisalhamento na intensidade e na direção. O jato em baixos níveis foi predominante de leste com intensidade média de 9 ms-1 e ocorreu em torno de 800 hPa. Ele foi mais intenso e mais profundo para as linhas que se propagaram mais de 400 km e menos intenso e menos profundo para as linhas costeiras. Os anos de 2005 e 2006 tiveram um aumento considerável de casos, em especial para as linhas que se propagaram. 2005 foi um ano atípico, pois foi verificado um aumento na temperatura da superfície do mar do Atlântico tropical, o que permitiu especular que aumentos como o que foi verificado, em certas áreas do Oceano Atlântico, pode levar ao aprofundamento do JBN através da intensificação das ondas de leste e assim favorecer a formação de mais LI na costa norte do Brasil. O JBN tem papel importante no processo de desenvolvimento das torres de cúmulos que compõe as linhas de instabilidade. Não só são responsáveis pela organização do sistema em linha, mas influenciam diretamente nos processos internos das nuvens, como ventilação e entranhamento, a formação de correntes descendentes e a formação de frentes de rajada em superfície que, em última instância, definem as características de propagação.

The aim of this work is to contribute to the understanding the processes that define the propagation of Amazon Tropical Squall Lines (ASL). 9 years of satellite images were analyzed defining ASL cases and their relationship with environment characteristics. The low level jet (LLJ) in ASL propagation has emerged as an important feature and possible differences between the systems that propagated and systems that did not propagate were analyzed. The observational analyzes suggested a series of numerical simulations with BRAMS model to explore the sensitivity of propagating ASL with respect to the kinematic characteristics of environment. Main results show that the larger number of ASL cases was of non…

Advisors/Committee Members: Dias, Maria Assuncao Faus da Silva, Souza, Enio Pereira de.

Subjects/Keywords: Amazonia; Amazônia; Jatos de Baixos Níveis; Linhas de Instabilidade; Low Level Jet; Squall line

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Alcântara, C. R. (2010). Um estudo da relação entre jatos de baixos níveis e linhas de instabilidade da Amazônia. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/14/14133/tde-25062013-202138/ ;

Chicago Manual of Style (16^th Edition):

Alcântara, Clênia Rodrigues. “Um estudo da relação entre jatos de baixos níveis e linhas de instabilidade da Amazônia.” 2010. Doctoral Dissertation, University of São Paulo. Accessed January 18, 2021. http://www.teses.usp.br/teses/disponiveis/14/14133/tde-25062013-202138/ ;.

MLA Handbook (7^th Edition):

Alcântara, Clênia Rodrigues. “Um estudo da relação entre jatos de baixos níveis e linhas de instabilidade da Amazônia.” 2010. Web. 18 Jan 2021.

Vancouver:

Alcântara CR. Um estudo da relação entre jatos de baixos níveis e linhas de instabilidade da Amazônia. [Internet] [Doctoral dissertation]. University of São Paulo; 2010. [cited 2021 Jan 18]. Available from: http://www.teses.usp.br/teses/disponiveis/14/14133/tde-25062013-202138/ ;.

Council of Science Editors:

Alcântara CR. Um estudo da relação entre jatos de baixos níveis e linhas de instabilidade da Amazônia. [Doctoral Dissertation]. University of São Paulo; 2010. Available from: http://www.teses.usp.br/teses/disponiveis/14/14133/tde-25062013-202138/ ;

Iowa State University

13. Vertz, Nicholas. Can model errors in atmospheric variables within the low-level inflow region of mesoscale convective systems be used to anticipate displacement errors in initiation location?.

Degree: 2018, Iowa State University

URL: https://lib.dr.iastate.edu/etd/16892

► Nocturnal Mesoscale Convective Systems (MCS) are frequent over the Great Plains in the summer, and the Great Plains low-level jet (LLJ) is a contributing factor… (more)

▼ Nocturnal Mesoscale Convective Systems (MCS) are frequent over the Great Plains in the summer, and the Great Plains low-level jet (LLJ) is a contributing factor to their initiation and evolution. Moisture brought in by the LLJ plays a key role in the formation and sustenance of MCSs. Thus, the ability of models to depict specific humidity as well as equivalent potential temperature (𝜃𝑒) flowing into the region where convection initiates is likely to play a role in how accurately they forecast MCSs. The Weather Research and Forecasting (WRF) model was used to examine the relationship between displacement errors for the initiating MCSs, and moisture and temperature errors that were present up to three hours before initiation upstream of the MCSs in WRF model simulations. A total of 18 cases are examined and differentiated into two groups based on a strongly and weakly forced synoptic environment. Rapid Update Cycle (RUC) analyses were used to represent observations, and all analyses were focused in 3 layers below 1500 m AGL. The WRF was configured to use the Thompson microphysics scheme and 2 planetary boundary layer (PBL) schemes (Yonsei University (YSU) and Mellor-Yamada-Janjic (MYJ)). Correlations were explored and discovered in regions near and upstream of both observed and simulated MCSs between the mean errors of both moisture variables, and the distances between simulated and observed MCS initiations. Correlations varied depending on the synoptic environment. A large dry bias resulting in a simulated MCS initiating further downstream from the observed MCS with respect to the low-level flow in a strongly forced-synoptic regime, to a small dry bias resulting in a simulated MCS to initiate far the observed MCS with respect to the left or right direction of the inflow direction (in a weakly forced-synoptic regime). The statistically significant correlations were present at all times examined, suggesting that forecasters might be able to anticipate how to adjust a WRF forecast based on the errors seen a few hours prior to MCS initiation.

Subjects/Keywords: Displacement Errors; Initiation; Low Level Jet; Mesoscale Convective System; Moisture; Nocturnal; Meteorology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Vertz, N. (2018). Can model errors in atmospheric variables within the low-level inflow region of mesoscale convective systems be used to anticipate displacement errors in initiation location?. (Thesis). Iowa State University. Retrieved from https://lib.dr.iastate.edu/etd/16892

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Vertz, Nicholas. “Can model errors in atmospheric variables within the low-level inflow region of mesoscale convective systems be used to anticipate displacement errors in initiation location?.” 2018. Thesis, Iowa State University. Accessed January 18, 2021. https://lib.dr.iastate.edu/etd/16892.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Vertz, Nicholas. “Can model errors in atmospheric variables within the low-level inflow region of mesoscale convective systems be used to anticipate displacement errors in initiation location?.” 2018. Web. 18 Jan 2021.

Vancouver:

Vertz N. Can model errors in atmospheric variables within the low-level inflow region of mesoscale convective systems be used to anticipate displacement errors in initiation location?. [Internet] [Thesis]. Iowa State University; 2018. [cited 2021 Jan 18]. Available from: https://lib.dr.iastate.edu/etd/16892.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Vertz N. Can model errors in atmospheric variables within the low-level inflow region of mesoscale convective systems be used to anticipate displacement errors in initiation location?. [Thesis]. Iowa State University; 2018. Available from: https://lib.dr.iastate.edu/etd/16892

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Iowa State University

14. Samman, Ahmad Emad. On the climatology and dynamics of heavy rainfall events and the winter low level jet in and near Saudi Arabia.

Degree: 2019, Iowa State University

URL: https://lib.dr.iastate.edu/etd/17092

► This study supports the weather organizations in Saudi Arabia (SA) and possibly the surrounding countries by providing new understanding of the weather systems that produce… (more)

▼ This study supports the weather organizations in Saudi Arabia (SA) and possibly the surrounding countries by providing new understanding of the weather systems that produce heavy rainfall and the dynamics that are involved. The study focuses generally on classifying the synoptic patterns inducing heavy rainfall in SA and specifically on understanding the climatology of the Red Sea Low Level Jet (RSLLJ) and its role in moisture advection toward the central Red Sea as well as understanding the dynamics behind the jet formation. The study uses 15 years of observed daily rainfall and the National Center for Environmental Prediction-National Center for Atmospheric Research (NCEP/UCAR) reanalysis data set to classify the synoptic patterns using a correlation-based map pattern classification. The ERA-Interim dataset from the European Center for Medium-Range Weather Forecasts (ECMWF) was used to create a detailed climatology of the RSLLJ for a 10-year period. The structure and the causes of the RSLLJ were investigated using the Weather Research and Forecasting (WRF) model and the National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) analyses data set. The results summarize six major synoptic features and classify 28 detailed synoptic patterns emerging from 186 cases of heavy rainfall in SA. The results also reveal that the RSLLJ is a relatively frequent phenomenon and the frequency of its occurrence varies according to location. The jet was found to have a significant role in moisture advection toward the central Red Sea area, which can contribute toward precipitation there. A linear relationship between the RSLLJ speed and the mean moisture concentration was observed in the central Red Sea region, where more moisture content was associated with greater jet speed. As for the jet causes, WRF simulations confirm that the RSLLJ is a terrain induced phenomenon that initiates as a gap flow as the jet forms north of the strait of Bab el-Mandab as a result of a hydraulic effect when a stably stratified cool layer is channeled through the mountainous gap at low levels over the strait into the southern Red Sea. In addition, because the WRF successfully simulated the structure of the RSLLJ, the results reveal the usefulness of numerical simulations as an important analytical tool to investigate and examine weather phenomena in locations with scarce observations, as in the case of the RSLLJ.

Subjects/Keywords: Heavy rainfall; Low level jet; Moisture flux; Saudi Arabia; Synoptic classification; The Red Sea; Meteorology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Samman, A. E. (2019). On the climatology and dynamics of heavy rainfall events and the winter low level jet in and near Saudi Arabia. (Thesis). Iowa State University. Retrieved from https://lib.dr.iastate.edu/etd/17092

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Samman, Ahmad Emad. “On the climatology and dynamics of heavy rainfall events and the winter low level jet in and near Saudi Arabia.” 2019. Thesis, Iowa State University. Accessed January 18, 2021. https://lib.dr.iastate.edu/etd/17092.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Samman, Ahmad Emad. “On the climatology and dynamics of heavy rainfall events and the winter low level jet in and near Saudi Arabia.” 2019. Web. 18 Jan 2021.

Vancouver:

Samman AE. On the climatology and dynamics of heavy rainfall events and the winter low level jet in and near Saudi Arabia. [Internet] [Thesis]. Iowa State University; 2019. [cited 2021 Jan 18]. Available from: https://lib.dr.iastate.edu/etd/17092.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Samman AE. On the climatology and dynamics of heavy rainfall events and the winter low level jet in and near Saudi Arabia. [Thesis]. Iowa State University; 2019. Available from: https://lib.dr.iastate.edu/etd/17092

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Minnesota

15. Harding, Keith John Iliff. Examining the drivers of current and future changes in Central U.S. warm-season rainfall.

Degree: PhD, Land and Atmospheric Science, 2014, University of Minnesota

URL: http://hdl.handle.net/11299/168213

► Warm-season precipitation in the Central U.S. is highly variable, as severe droughts and flooding often occur in consecutive years or simultaneously. Some of the most… (more)

▼ Warm-season precipitation in the Central U.S. is highly variable, as severe droughts and flooding often occur in consecutive years or simultaneously. Some of the most highly productive agricultural lands are present within the region despite susceptibility to warm-season rainfall extremes. Climate change is expected to increase precipitation extremes globally, but how warm-season Central U.S. precipitation will be affected is unclear. In this study, I examine the drivers of current and future warm-season precipitation in the region as well as how the basic characteristics of summer rainfall may be affected by climate change through the use of gridded observations, reanalysis datasets, and dynamical downscaling of global climate models (GCMs). It is demonstrated that the negative phase of the Pacific-North American (PNA) teleconnection pattern enhances heavy precipitation events over the Upper Midwest by modulating the strength of the Great Plains Low Level Jet (GPLLJ), possibly enabling greater medium range prediction of Midwest heavy rain events. Similarly, I aim to reduce uncertainty in long-term projections of how precipitation may be affected by climate change by examining shortfalls in GCM-simulated warm-season precipitation and demonstrating improvement with dynamical downscaling. Using the Weather Research and Forecasting (WRF) model, two GCMs are dynamically downscaled in one historical and three future timeslices with varying anthropogenic forcing. Future warm-season precipitation in these simulations is more intense, less frequent, and occurs with more days between rain events, similar to trends in observations that show large increases in extreme rainfall events and rainfall intensity. The intensification of extreme rainfall events in future simulations is the strongest during the April-July, associated with a strengthening of the GPLLJ during those months. Heavier rainfall rates during extreme precipitation events are related to a stronger cold pool and mesohigh, which force stronger moisture convergence above the cold pool in the presence of additional low-level moisture and a drier mid-troposphere. Overall, the identification of plausible physical mechanisms that might contribute to the enhancement of heavy rainfall events in the region enables greater confidence in future projections of extreme rainfall events.

Subjects/Keywords: Climate change; Drought; Dynamical downscaling; Extreme precipitation; Low-level jet; Land and atmospheric science

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Harding, K. J. I. (2014). Examining the drivers of current and future changes in Central U.S. warm-season rainfall. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/168213

Chicago Manual of Style (16^th Edition):

Harding, Keith John Iliff. “Examining the drivers of current and future changes in Central U.S. warm-season rainfall.” 2014. Doctoral Dissertation, University of Minnesota. Accessed January 18, 2021. http://hdl.handle.net/11299/168213.

MLA Handbook (7^th Edition):

Harding, Keith John Iliff. “Examining the drivers of current and future changes in Central U.S. warm-season rainfall.” 2014. Web. 18 Jan 2021.

Vancouver:

Harding KJI. Examining the drivers of current and future changes in Central U.S. warm-season rainfall. [Internet] [Doctoral dissertation]. University of Minnesota; 2014. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/11299/168213.

Council of Science Editors:

Harding KJI. Examining the drivers of current and future changes in Central U.S. warm-season rainfall. [Doctoral Dissertation]. University of Minnesota; 2014. Available from: http://hdl.handle.net/11299/168213

16. Jameson, Dale A. Synoptic conditions of the low-level jet over West Texas.

Degree: Atmospheric Science, 2010, Texas Tech University

URL: http://hdl.handle.net/2346/ETD-TTU-2010-12-1076

► The low-level jet is common to West Texas. This thesis will focus on the synoptic conditions that occur during low-level jet events during the boundary… (more)

Subjects/Keywords: Low level Jet; Synoptic; Texas; West Texas; Synoptic low level jet; Synoptic conditions; Low level jet synoptic conditions

…CHAPTER I INTRODUCTION The low-level jet is a strong wind concentrated in the atmospheric… …the United States (Stull, 1988). The low-level jet in the Great Plains occurs most… …forcing mechanisms that can account for the formation of the low-level jet, from boundary layer… …development of a low-level jet (Igau and Nielsen-Gammon, 1998). Hourly observations are… …low-level jet (Whiteman et al., 1997). This thesis will focus on the synoptic…

10 more images…

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Jameson, D. A. (2010). Synoptic conditions of the low-level jet over West Texas. (Thesis). Texas Tech University. Retrieved from http://hdl.handle.net/2346/ETD-TTU-2010-12-1076

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Jameson, Dale A. “Synoptic conditions of the low-level jet over West Texas.” 2010. Thesis, Texas Tech University. Accessed January 18, 2021. http://hdl.handle.net/2346/ETD-TTU-2010-12-1076.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Jameson, Dale A. “Synoptic conditions of the low-level jet over West Texas.” 2010. Web. 18 Jan 2021.

Vancouver:

Jameson DA. Synoptic conditions of the low-level jet over West Texas. [Internet] [Thesis]. Texas Tech University; 2010. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2346/ETD-TTU-2010-12-1076.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Jameson DA. Synoptic conditions of the low-level jet over West Texas. [Thesis]. Texas Tech University; 2010. Available from: http://hdl.handle.net/2346/ETD-TTU-2010-12-1076

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Texas Tech University

17. Giammanco, Ian Matthew. An observational study of the South Plains nocturnal low-level jet.

Degree: Geosciences, 2005, Texas Tech University

URL: http://hdl.handle.net/2346/1177

► The presence of nocturnal low-level jet streams across the Great Plains of the United States has been well documented over the last fifty years. These… (more)

Subjects/Keywords: Low level jet; Turbulence; Kelvin-Helmholtz; Wind energy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Giammanco, I. M. (2005). An observational study of the South Plains nocturnal low-level jet. (Thesis). Texas Tech University. Retrieved from http://hdl.handle.net/2346/1177

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Giammanco, Ian Matthew. “An observational study of the South Plains nocturnal low-level jet.” 2005. Thesis, Texas Tech University. Accessed January 18, 2021. http://hdl.handle.net/2346/1177.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Giammanco, Ian Matthew. “An observational study of the South Plains nocturnal low-level jet.” 2005. Web. 18 Jan 2021.

Vancouver:

Giammanco IM. An observational study of the South Plains nocturnal low-level jet. [Internet] [Thesis]. Texas Tech University; 2005. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2346/1177.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Giammanco IM. An observational study of the South Plains nocturnal low-level jet. [Thesis]. Texas Tech University; 2005. Available from: http://hdl.handle.net/2346/1177

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Texas – Austin

18. Liu, Weiran, Ph. D. Understanding precipitation variability over Africa : observational analysis and regional climate model simulations.

Degree: PhD, Geological Sciences, 2020, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/9197

► Understanding precipitation variability over Africa is important because this region experiences rainfall events that influence agriculture and economic infrastructure, and threaten lives regularly. This study… (more)

▼ Understanding precipitation variability over Africa is important because this region experiences rainfall events that influence agriculture and economic infrastructure, and threaten lives regularly. This study aims to advance our understanding of African precipitation across different timescales, from diurnal cycle to interannual variations, using observations, reanalyses, and regional climate model simulations. First, we evaluate the role of MCSs in the total rainfall distribution as a function of season from a climatological perspective (1998-2014) over sub-Saharan northern Africa and examine how the diurnal cycle of rainfall changes with season. The percentages of the full TRMM precipitation delivered by MCSs have meridional structures in spring, fall and winter, while the percentages are homogenous in summer (>80%). The diurnal peaks are classified into three categories: single afternoon peak, continuous afternoon peak, and nocturnal peak. The continuous afternoon peak combines rainfall from two system types –one locally-generated and one propagating. The seasonality of the diurnal cycle is related to the seasonality of MCS lifetimes, and propagation speeds and directions. Second, a low-level jet, the West African westerly jet, is investigated over the West African coast. In the western Sahel (0°-10°W, 8°-18°N), the moisture flux associated with the jet is stronger than that associated with the southerly West African monsoon flow from July 5 to August 20 (45 days). The moisture budget analysis reveals that the seasonal evolution of the rainfall in this analysis region is associated with zonal moisture convergence related to changes of the jet. Finally, three sub-regions of the Indian Ocean in which SSTs significantly influence the equatorial East African short rains on interannual timescales are identified, and the physical processes of this influence are studied using regional climate model simulations. SSTAs in the western Indian Ocean exert a stronger influence on the short rains than central and eastern Indian Ocean SSTAs both in terms of the coverage of significantly-changed precipitation and the magnitude of the precipitation response. The mechanisms of this influence are diagnosed using atmospheric moisture budget and moist static energy analyses, with reference to Kelvin and Rossby wave generation as in the Gill model, but in the presence of complicated topography and nonzero background flows. Advisors/Committee Members: Cook, Kerry H. (advisor), Yang, Zongliang (committee member), Heimbach, Patrick (committee member), Okumura, Yuko (committee member), Vizy, Edward (committee member).

Subjects/Keywords: MCS; Diurnal cycle of precipitation; Sahel rainfall; Low-level jet; West African monsoon; Seasonality of precipitation; West African westerly jet; Saharan thermal low; East African precipitation; Short rains; Kenya precipitation; Indian Ocean Dipole; Interannual variability; Tropical Africa rainfall; SST forcing; Greater Horn of Africa

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Liu, Weiran, P. D. (2020). Understanding precipitation variability over Africa : observational analysis and regional climate model simulations. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/9197

Chicago Manual of Style (16^th Edition):

Liu, Weiran, Ph D. “Understanding precipitation variability over Africa : observational analysis and regional climate model simulations.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed January 18, 2021. http://dx.doi.org/10.26153/tsw/9197.

MLA Handbook (7^th Edition):

Liu, Weiran, Ph D. “Understanding precipitation variability over Africa : observational analysis and regional climate model simulations.” 2020. Web. 18 Jan 2021.

Vancouver:

Liu, Weiran PD. Understanding precipitation variability over Africa : observational analysis and regional climate model simulations. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Jan 18]. Available from: http://dx.doi.org/10.26153/tsw/9197.

Council of Science Editors:

Liu, Weiran PD. Understanding precipitation variability over Africa : observational analysis and regional climate model simulations. [Doctoral Dissertation]. University of Texas – Austin; 2020. Available from: http://dx.doi.org/10.26153/tsw/9197

19. Ariane Frassoni dos Santos. Padrões sinóticos de circulação atmosférica associados ao jato em baixos níveis a leste da Cordilheira ds Andes, na América do Sul.

Degree: 2006, Instituto Nacional de Pesquisas Espaciais

URL: http://urlib.net/sid.inpe.br/[email protected]/2006/07.24.19.18

► Este estudo teve como objetivo identificar os padrões atmosféricos associados à formação, manutenção e dissipação do Jato em Baixos Níveis (JBN) da América do Sul(AS).… (more)

▼ Este estudo teve como objetivo identificar os padrões atmosféricos associados à formação, manutenção e dissipação do Jato em Baixos Níveis (JBN) da América do Sul(AS). Foram utilizadas as componentes zonal (u) e meridional (v) do vento, altura geopotencial(f), temperatura(T), umidade específica(q), entre outras variáveis meteorológicas, obtidas das reanálises do National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), durante o período de 1979 a 2003. Dados do South America Low-Level Jet Experiment (SALLJEX) na estação de Mariscal Estigarríbia, no Paraguai (6 a 9 de julho de 2003) e na estação de Santa Cruz de la Sierra na Bolívia (19 a 24 de janeiro de 2003) também foram utilizados. Inicialmente, fez-se uma climatologia do JBN fazendo-se modificações no Critério 1 de Bonner (C1BM) e também utilizando-se o Critério 1 de Bonner Modificado (C1M). Nesta análise, foram observadas diferenças entre o verão e o inverno, de acordo com a latitude considerada (ao norte ou ao sul de 20 S), tanto na quantidade de casos de JBN como em sua intensidade. Foram identificados mais casos de JBN no inverno utilizando o C1M e mais casos de JBN durante o verão com o C1BM. Esta diferença está relacionada ao posicionamento da Alta Subtropical do Atlântico Sul (ASAS) e `a entrada de sistemas frontais no continente. Para verificar os padrões atmosféricos que pudessem estar associados ao JBN foi utilizada a técnica de Funções Ortogonais Empíricas (do inglês Empirical Ortoghonal Functions - EOF) para a análise do campo de anomalia da média diária de v em 850 hPa (v ). Foram calculados campos compostos de vento, vorticidade relativa (?) em 850 hPa, divergência em 300 hPa e f em 1000 hPa e 300 hPa obtidos das Componentes Principais (CP) de v além de campos de correlação entre a primeira CP de v e campos de Pressão ao Nível médio do Mar e anomalia da média diária de u (u) em 850 hPa e 300 hPa. Dentre os principais padrões atmosféricos obtidos, destaca-se que o primeiro modo das EOF está associado ao posicionamento de ventos máximos a leste dos Andes e a um padrão típico de passagem de um trem de ondas sobre a AS. Este trem de ondas propaga-se para leste, sofre efeitos orográficos e amplia-se meridionalmente após cruzar os Andes, favorecendo a ocorrência de ciclogênese à sotavento das montanhas. Nesse instante também foi observada a intensificação de um anticiclone transiente sobre o Oceano Atlântico Sul. Este padrão favorece o fortalecimento dos ventos no lado leste das montanhas. Em altos níveis notou-se a propagação do Jato em Altos Níveis (JAN) em direção `a AS um dia antes da ocorrência dos ventos máximos. O segundo modo das EOF também apresentou um padrão do tipo onda. Entretanto, o campo composto utilizando a segunda CP para o verão mostrou um padrão de propagação de frentes que permanecem semi-estacionárias sobre a Região Sudeste do Brasil, evidenciando episódios de ZCAS. A análise dos campos compostos de vento em 850 hPa, 700 hPa e 300 hPa, temperatura potencial equivalente (? ) em e 850 hPa e… Advisors/Committee Members: Iracema Fonseca de Albuquerque Cavalcanti, Manoel Alonso Gan, Marley Cavalcante de Lima Moscati, Marcelo Enrique Seluchi, Rosmeri Porfírio da Rocha.

Subjects/Keywords: METEOROLOGIA; Jatos em baixos níveis; Circulação atmosférica; Padrões sinóticos; Cordilheira dos Andes; América do Sul; METEOROLOGY; Low-level jet; Atmospheric circulation; Synoptic patterns; Andes Cordillera; South America

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Santos, A. F. d. (2006). Padrões sinóticos de circulação atmosférica associados ao jato em baixos níveis a leste da Cordilheira ds Andes, na América do Sul. (Thesis). Instituto Nacional de Pesquisas Espaciais. Retrieved from http://urlib.net/sid.inpe.br/[email protected]/2006/07.24.19.18

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Santos, Ariane Frassoni dos. “Padrões sinóticos de circulação atmosférica associados ao jato em baixos níveis a leste da Cordilheira ds Andes, na América do Sul.” 2006. Thesis, Instituto Nacional de Pesquisas Espaciais. Accessed January 18, 2021. http://urlib.net/sid.inpe.br/[email protected]/2006/07.24.19.18.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Santos, Ariane Frassoni dos. “Padrões sinóticos de circulação atmosférica associados ao jato em baixos níveis a leste da Cordilheira ds Andes, na América do Sul.” 2006. Web. 18 Jan 2021.

Vancouver:

Santos AFd. Padrões sinóticos de circulação atmosférica associados ao jato em baixos níveis a leste da Cordilheira ds Andes, na América do Sul. [Internet] [Thesis]. Instituto Nacional de Pesquisas Espaciais; 2006. [cited 2021 Jan 18]. Available from: http://urlib.net/sid.inpe.br/[email protected]/2006/07.24.19.18.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Santos AFd. Padrões sinóticos de circulação atmosférica associados ao jato em baixos níveis a leste da Cordilheira ds Andes, na América do Sul. [Thesis]. Instituto Nacional de Pesquisas Espaciais; 2006. Available from: http://urlib.net/sid.inpe.br/[email protected]/2006/07.24.19.18

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

20. Wagner Rodrigues Soares. Caracterização dos fluxos de umidade sobre a América do Sul associados ao jato de baixos níveis ao leste dos Andes utilizando o modelo HadRM3P em um cenário de aquecimento global.

Degree: 2008, Instituto Nacional de Pesquisas Espaciais

URL: http://urlib.net/sid.inpe.br/[email protected]/2008/12.03.18.08

►

O modelo regional HadRM3P do Hadley Centre foi utilizado para avaliar os fluxos de umidade e o Jato de Baixos Níveis na América do Sul… (more)

▼

O modelo regional HadRM3P do Hadley Centre foi utilizado para avaliar os fluxos de umidade e o Jato de Baixos Níveis na América do Sul em dois períodos: o primeiro pode ser entendido como o clima atual e abrange o período de 1980 até 1989. O segundo, abrange o período de 2080 até 2089 e projeta um possível clima de aquecimento global a partir do cenário de altas emissões de gases de efeito estufa SRES A2 do IPCC. Os resultados são analisados em termos de transporte de umidade integrado verticalmente na baixa atmosfera, fluxos de umidade em fronteiras laterais de duas áreas representativas das bacias Amazônica e Paraná-Prata. Para analisar o transporte de umidade mais intenso no lado leste dos Andes, foram construídos compostos de Jatos de Baixos Níveis da América do Sul a partir da aplicação de um critério em função da velocidade do vento e do cisalhamento vertical. Integrações ao longo das fronteiras laterais mostraram que pode existir maior quantidade de umidade disponível para alimentar sistemas convectivos de mesoescala que ocorrem na bacia Paraná-Prata no cenário de altas emissões do IPCC quando se compara com o clima atual. Isso acontece em virtude do maior fluxo para o sul associado ao jato que transporta umidade da bacia Amazônica. Também observou-se que a presença do jato afeta a convergência de umidade nas bacias Amazônica e Paraná-Prata tanto no clima atual quanto no clima mais quente. Maior transporte de umidade na baixa atmosfera em direção à região da bacia Paraná-Prata associado à presença de jatos mais freqüentes e intensos, foi observado num possível clima de forte aquecimento global em relação ao clima atual.

The HadRM3P regional model from the IK Hadley Centre has been used to assess the moisture flux and the Low-Level Jet east of the Andes in South America in two periods: the first one can be understood as the current climate and covers the period from 1980 to 1989, and the second one covers the period from 2080 to 2089 under a future global warming scenario under high greenhouse gases emissions as projected by the IPCC SRES A2 scenario. The results are analyzed in relation to the vertically integrated moisture transport in the low-level moisture flux between two important areas of South America: theAmazon and Paraná-Prata river basins. To analyze the transport of more intense moisture east of the Andes, composites of the South American Low-Level Jet were built based on wind speed and vertical wind shear. Integrations along the lateral boundaries of the two basins show that there could be a large higher amount of moisture available to feed the mesoscale convective systems which occur in the Paraná-Prata basin in the IPCC scenario, as compared to the present. This is because of the increased flow to the south associated with the Low-Level Jet bringing moisture from the Amazon basin. It was also observed that the presence of the Low-Level Jet affects moisture convergence in the Amazon basin in the current climate as well as in the warmer climate. In the future high-emission scenario A2, a more…

Advisors/Committee Members: Iracema Fonseca de Albuquerque Cavalcanti, José Antonio Marengo Orsini, Tércio Ambrizzi, Andrea Celeste Saulo, Rosa de Fátima Cruz Marques.

Subjects/Keywords: Andes; Jato de baixos níveis; mudanças climáticas; transporte de umidade; modelo HadRM3P; IPCC; aquecimento global; Andes; low-level jet; climate change; moisture transport; HadRM3P model; IPCC; global worming

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Soares, W. R. (2008). Caracterização dos fluxos de umidade sobre a América do Sul associados ao jato de baixos níveis ao leste dos Andes utilizando o modelo HadRM3P em um cenário de aquecimento global. (Thesis). Instituto Nacional de Pesquisas Espaciais. Retrieved from http://urlib.net/sid.inpe.br/[email protected]/2008/12.03.18.08

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Soares, Wagner Rodrigues. “Caracterização dos fluxos de umidade sobre a América do Sul associados ao jato de baixos níveis ao leste dos Andes utilizando o modelo HadRM3P em um cenário de aquecimento global.” 2008. Thesis, Instituto Nacional de Pesquisas Espaciais. Accessed January 18, 2021. http://urlib.net/sid.inpe.br/[email protected]/2008/12.03.18.08.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Soares, Wagner Rodrigues. “Caracterização dos fluxos de umidade sobre a América do Sul associados ao jato de baixos níveis ao leste dos Andes utilizando o modelo HadRM3P em um cenário de aquecimento global.” 2008. Web. 18 Jan 2021.

Vancouver:

Soares WR. Caracterização dos fluxos de umidade sobre a América do Sul associados ao jato de baixos níveis ao leste dos Andes utilizando o modelo HadRM3P em um cenário de aquecimento global. [Internet] [Thesis]. Instituto Nacional de Pesquisas Espaciais; 2008. [cited 2021 Jan 18]. Available from: http://urlib.net/sid.inpe.br/[email protected]/2008/12.03.18.08.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Soares WR. Caracterização dos fluxos de umidade sobre a América do Sul associados ao jato de baixos níveis ao leste dos Andes utilizando o modelo HadRM3P em um cenário de aquecimento global. [Thesis]. Instituto Nacional de Pesquisas Espaciais; 2008. Available from: http://urlib.net/sid.inpe.br/[email protected]/2008/12.03.18.08

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Uppsala University

21. Johansson, Petra. Low-level jets – observationer från Näsudden på Gotland.

Degree: LUVAL, 2004, Uppsala University

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303861

►

Vid luftens passage från en typ av yta till en annan byggs ett internt gränsskikt upp där luftens egenskaper förändras successivt. Detta är grunden… (more)

▼

Vid luftens passage från en typ av yta till en annan byggs ett internt gränsskikt upp där luftens egenskaper förändras successivt. Detta är grunden för bl.a. bildandet av advekterade low-level jets orsakade av en tröghetssvängning, vilken har sitt ursprung i att under vissa förhållanden erhålls obalans mellan de krafter som påverkar vinden. Målet med arbetet var att kartlägga inflytandet av low-level jets på vindprofilen på Näsudden, Gotland, ovan 100 m höjd. För detta syfte användes mätningar under perioden maj 2000 till juli 2001 gjorda i tre mätmaster i området. En mätmast var placerad på land 1.5 km från Näsuddens kust-linje, en andra mast precis vid kustlinjen och en tredje mast ute i Östersjön 4.6 km från kusten. Eftersom masten ute i havet var placerad mitt i Bockstigens vindpark, omgiven av fem vindturbiner, påverkades vindmätningarna av turbinvakar i vissa riktningssektorer. Genom jämförelser mellan vindmätningar i masten och på turbinerna i för masten ostörda sektorer, togs en korrektion fram så att vind-mätningarna gjorda på turbinerna kunde användas i de sektorer mastmätningarna stördes av turbinvakar. För att kunna studera påverkan av low-level jets på vindprofilen användes data från Bockstigens vindpark tillsammans med en vindmodell, byggd på rörelseekvationerna, Monin-Obukhovs similaritetsteori och K-teori. Modellen, som ej kan generera low-level jets, användes för att beräkna vindprofilerna över havet och hur dessa vind-profiler modifierades vid passagen av kusten. Resultatet från modellen jämfördes sedan med observationer från den 145 m höga masten på Näsudden, 1.5 km från kusten. Det visade sig att de observerade vindhastigheterna på 145 m höjd i medeltal var ca 0.8 m/s högre än vad som beräknats med modellen vid vindriktningar från havet in över Näsudden, vilket kan antas bero på inflytandet från low-level jets. Under månaderna mars till maj är vattnet i Ösersjön klimatologiskt sett mycket kallare än luften, ett förhållande som är fördelaktigt för bildandet av low-level jets. Det visade sig att under dessa månader var vindhastigheten mätt på 145 m höjd inom vind-riktningssektorn 220°-250° hela 1.7 m/s högre än vad som beräknades med vind-modellen, vilket understryker betydelsen av low-level jets under denna del av året. Under resten av året befanns skillnaden mellan observerad och modellberäknad vindhastighet på 145 m höjd vara ca 0.8 m/s för samma vindriktningar.

When air is flowing from one type of surface to another, an internal boundary layer is built up where the properties of the air gradually change. This is the basic condition for the development of for example advected low-level jets caused by inertial oscillations, whose origin is that under certain conditions an imbalance will occur between the forces driving the wind. The purpose with the present work was to map the influence from low-level jets on the wind profile at Näsudden, Gotland, above 100 m height. For this purpose, measurements taken on three towers in the area during the period May 2000 to July…

Subjects/Keywords: low-level jet; tröghetssvängning; vindmodell; modellutvärdering; Meteorology and Atmospheric Sciences; Meteorologi och atmosfärforskning

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APA (6^th Edition):

Johansson, P. (2004). Low-level jets – observationer från Näsudden på Gotland. (Thesis). Uppsala University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303861

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Johansson, Petra. “Low-level jets – observationer från Näsudden på Gotland.” 2004. Thesis, Uppsala University. Accessed January 18, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303861.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Johansson, Petra. “Low-level jets – observationer från Näsudden på Gotland.” 2004. Web. 18 Jan 2021.

Vancouver:

Johansson P. Low-level jets – observationer från Näsudden på Gotland. [Internet] [Thesis]. Uppsala University; 2004. [cited 2021 Jan 18]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303861.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Johansson P. Low-level jets – observationer från Näsudden på Gotland. [Thesis]. Uppsala University; 2004. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303861

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Delft University of Technology

22. Jonker, R.G. (author). Homogeneous detached composite breakwater: CFD study of the design sensitivities in the 2D geometrical layout using a detached homogeneous low-crested structure to reduce sea wall overtopping.

Degree: 2020, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:228aaffe-b730-4175-b880-70e14ff4cd87

► In this research OpenFOAM is used to model and determine the complex hydrodynamic behaviour of a Homogeneous low-crested structure (HLCS) consisting of cubipod artificial concrete… (more)

▼ In this research OpenFOAM is used to model and determine the complex hydrodynamic behaviour of a Homogeneous low-crested structure (HLCS) consisting of cubipod artificial concrete elements. The validated model is used to gain insight in the design sensitivities of a two dimensional cross sectional layout to reduce sea wall overtopping. HLCS and Low-crested structure (LCS) in general dissipate energy from the incoming wave field by wave breaking over the crest of the structure and porous flow through the structure. By energy dissipation milder wave conditions are created inside the basin between the HLCS and the sea wall. Milder wave conditions result in reduced hydrodynamic loads on the sea wall and reduced flood risk. However not only the milder wave conditions determine the amount of sea wall overtopping. Additionally wave-induced water level set-up and basin hydrodynamics (i.e. seiching and resonance) contribute to the amount of overtopping. The relative importance of these different hydrodynamic interactions on sea wall overtopping depend on the main geometrical layout parameters of the system. The main geometrical layout parameters that are analysed in this research are the crest height of the HLCS (푅c ), the crest width of the HLCS (퐵) and the basin length between the HLCS and the sea wall (퐿pool). These geometrical layout parameters can be used by the engineer to steer the hydrodynamic behaviour towards the most cost effective design to reduce sea wall overtopping. However, due to the complexity of physical processes involved and their interactions, theoretical analysis is cumbersome. Therefore advanced OpenFOAM Computational Fluid Dynamics (CFD) simulations are performed in this research. These simulations are used to capture the complex hydrodynamics and gain more insight in the design sensitivities of these types of hydrodynamic systems. A coupled numerical model using both OceanWave3D and OpenFOAM has been set-up in this research. Model dimensions are based on conducted physical model experiments to assess the amount of wave transmission over HLCS as described in J. Medina et al. (2019). No raw data was available from these physical model experiments. Therefore the wave flume hydrodynamics (i.e. irregular wave characteristics) have been calibrated using a grid resolution study. In this study also simulations with varying courant numbers have been performed. Both extracted statistical wave parameters of the coupled model and a standalone OceanWave3D model have been compared. Additionally the separate output of OceanWave3D and OpenFOAM within the coupled model have been compared. Grid convergence has been found for increasing OpenFOAM grid resolution. The measured mean overtopping discharges from the OpenFOAM model are validated against Eurotop 2018 prediction guidelines. The grid which showed the most accurate results in comparison to the required computational time has been selected for the remainder of the study. This OpenFOAM grid is characterized a grid resolution of Δx = Δy= 퐻s/10. In order to assess… Advisors/Committee Members: Antonini, A. (mentor), Hofland, B. (graduation committee), Smith, G.M. (graduation committee), Zoon, Arthur (mentor), Delft University of Technology (degree granting institution).

Subjects/Keywords: OpenFOAM; Coastal Engineering; Breakwater; Detached breakwater; Coastal structures; Coastal defense; OceanWave3D; Concrete armour unit; Cubipod; Overtopping; Wave Transformations; Wave transmission; Water level set-up; Seiching; Basin hydrodynamics; Numerical modeling; Hydrodynamic system; Porosity; Porosity distribution; Design sensitivities; Porous Media; Homogeneous breakwater; Low-crested structure; Homogeneous low-crested structure; Coupled numerical model; Parametric study; Seawall; Flood Risk

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APA (6^th Edition):

Jonker, R. G. (. (2020). Homogeneous detached composite breakwater: CFD study of the design sensitivities in the 2D geometrical layout using a detached homogeneous low-crested structure to reduce sea wall overtopping. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:228aaffe-b730-4175-b880-70e14ff4cd87

Chicago Manual of Style (16^th Edition):

Jonker, R G (author). “Homogeneous detached composite breakwater: CFD study of the design sensitivities in the 2D geometrical layout using a detached homogeneous low-crested structure to reduce sea wall overtopping.” 2020. Masters Thesis, Delft University of Technology. Accessed January 18, 2021. http://resolver.tudelft.nl/uuid:228aaffe-b730-4175-b880-70e14ff4cd87.

MLA Handbook (7^th Edition):

Jonker, R G (author). “Homogeneous detached composite breakwater: CFD study of the design sensitivities in the 2D geometrical layout using a detached homogeneous low-crested structure to reduce sea wall overtopping.” 2020. Web. 18 Jan 2021.

Vancouver:

Jonker RG(. Homogeneous detached composite breakwater: CFD study of the design sensitivities in the 2D geometrical layout using a detached homogeneous low-crested structure to reduce sea wall overtopping. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Jan 18]. Available from: http://resolver.tudelft.nl/uuid:228aaffe-b730-4175-b880-70e14ff4cd87.

Council of Science Editors:

Jonker RG(. Homogeneous detached composite breakwater: CFD study of the design sensitivities in the 2D geometrical layout using a detached homogeneous low-crested structure to reduce sea wall overtopping. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:228aaffe-b730-4175-b880-70e14ff4cd87

Victoria University of Wellington

23. Wellwood, Joseph. Vulnerable Territories: The Perpetually Shifting Edge.

Degree: 2020, Victoria University of Wellington

URL: http://hdl.handle.net/10063/9207

► New Zealand’s coastline is rapidly receding. The increased threat of rising sea levels continues to erode the shore line causing extensive and irreparable damage to… (more)

▼ New Zealand’s coastline is rapidly receding. The increased threat of rising sea levels continues to erode the shore line causing extensive and irreparable damage to thousands of coastal properties, often dismantling communities and the kiwi dream of living near the ocean. With global temperatures continuing to rise, all of our coastal communities are at risk. The current measure of response to this issue is through managed retreat, the removal and relocation of all ‘at risk’ buildings in coastal hazard zones. While this approach is successful in preserving the physical structures, it remains an undesirable solution that forces homeowners to abandon their community and the coastline for the safety of higher ground. The retreat is hampered among debate within the effected regions as the forced detachment of long standing communities often results in the loss of ‘sense of place’ that living within a coastal community enables. This thesis proposes that Haumoana in Hawkes Bay offers the fitting location to introduce an alternative coastal community model that actively responds to the impending hazards whilst retaining the societal poetics. Situated just south of the nearby communities of Te Awanga and Haumoana, two of the most at-risk coastal regions in New Zealand that are currently facing the prospect of dismantlement. The site was specifically chosen due to the fact that erosion is predicted to diminish half its usable land over the next century, this thesis will investigate the potential risks to the respective coastline, the role that this would play in an adaptive community, and the possible design options that can respond and enhance a future sustainable landscape. This thesis argues that a coastal community can be designed to actively adapt and respond to the threat of erosion rather than being dismantled through retreat; that by adopting design principles that protect the land on which they are placed, the coastal hazards of the region can be lessened; and that an adaptive community model can be achieved whilst retaining the ‘sense of place’ that coastal community’s exhibit. The thesis proposes that this can be achieved by incorporating and reinforcing natural features of the coast into the architectural design at various scales; accommodating for, and adapting to the imminent threat of erosion; and by invoking principles of sustainable design in company with adaptive planning and resilient design, thereby pushing the standards of coastal planning beyond typical practice. Advisors/Committee Members: Wilhelm, Hans-Christian.

Subjects/Keywords: Coastal; Sea level rise; Erosion; Adaptive

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APA (6^th Edition):

Wellwood, J. (2020). Vulnerable Territories: The Perpetually Shifting Edge. (Masters Thesis). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/9207

Chicago Manual of Style (16^th Edition):

Wellwood, Joseph. “Vulnerable Territories: The Perpetually Shifting Edge.” 2020. Masters Thesis, Victoria University of Wellington. Accessed January 18, 2021. http://hdl.handle.net/10063/9207.

MLA Handbook (7^th Edition):

Wellwood, Joseph. “Vulnerable Territories: The Perpetually Shifting Edge.” 2020. Web. 18 Jan 2021.

Vancouver:

Wellwood J. Vulnerable Territories: The Perpetually Shifting Edge. [Internet] [Masters thesis]. Victoria University of Wellington; 2020. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10063/9207.

Council of Science Editors:

Wellwood J. Vulnerable Territories: The Perpetually Shifting Edge. [Masters Thesis]. Victoria University of Wellington; 2020. Available from: http://hdl.handle.net/10063/9207

University of Manchester

24. Xia, Qingfeng. Enhancement of liquids mixing using active pulsation in the laminar flow regime.

Degree: PhD, 2012, University of Manchester

URL: https://www.research.manchester.ac.uk/portal/en/theses/enhancement-of-liquids-mixing-using-active-pulsation-in-the-laminar-flow-regime(bcb5ff26-11c4-4301-bdc1-9cae46f46580).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553561

► Both the need for mixing highly viscous liquids more effectively and the advance of micro-scale applications urge the development of technologies for liquid mixing at… (more)

▼ Both the need for mixing highly viscous liquids more effectively and the advance of micro-scale applications urge the development of technologies for liquid mixing at low Reynolds numbers. However, currently engineering designs which offer effective jet mixing without structural and operational complexity are still lacking. In this project, the method of enhancing liquid mixing using active pulsation in the laminar flow regime is explored experimentally. This work started by improving the inline pulsation mechanism in an existing confined jet configuration whereby the fluid from a primary planar jet and two surrounding secondary planar jets are pulsated by active fluid injection control via solenoid valves in the out-of-phase mode. The influence of Reynolds number, pulsation modes, frequency, duty cycle on mixing is then investigated using PLIF and PIV experimental techniques. A combination of different mixing mechanisms is found to be at play, including sequential segmentation, shearing and stretching, vortex entrainment and breakup. At a given net flow Reynolds number, an optimal frequency exists which scales approximately with a Strouhal number (Str=fh/Uj) about 1. This optimal frequency reflects the compromise of the vorticity strength and segmentation length. Furthermore, a lower duty cycle is found to produce a better mixing due to a resultant higher instantaneous Reynolds number in the jet flow. Overall, the improvement of the rig has resulted in an excellent mixing being achieved at a net flow Reynolds number of 166 which is at least order of magnitude lower than in the original rig. In order to achieve fast laminar mixing at even lower Reynolds numbers, the active pulsation mechanism using lateral synthetic jet pairs is designed and tested at a net flow Reynolds number ranging from 2 to 166 at which a good mixing is achieved. The influence of actuation frequency and amplitude, and different jet configuration is evaluated using PLIF and PIV experimental techniques. At the mediate to high Reynolds numbers tested in this study, the interaction and subsequent breakup of vortices play a dominant role in provoking mixing. In contrast, at the lower end of Reynolds numbers the strength of vortex rollup is weakened significantly and as a result folding and shearing of sequential segments provide the main mechanism for mixing. Therefore it is essential to use multiple lateral synthetic jet pairs to achieve good mixing in both mixing channel and synthetic jet cavity at this Reynolds number. It is found that an increase in both the actuation magnitude and frequency improves mixing, thereby the velocity ratio represents the relative strength of the pulsation velocity to the mean flow velocity is crucial for mixing enhancement. In order to identify actuation conditions for good mixing, a regression fit is conducted for the correlation between the dimensionless parameters, net flow Reynolds number Ren, stroke length L and Strouhal number Str. Over the tested range of the net flow Reynolds number from 2 to 83, the…

Subjects/Keywords: 532.0525; Jet mixing; Synthetic jet; Low Reynolds numbers

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APA (6^th Edition):

Xia, Q. (2012). Enhancement of liquids mixing using active pulsation in the laminar flow regime. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/enhancement-of-liquids-mixing-using-active-pulsation-in-the-laminar-flow-regime(bcb5ff26-11c4-4301-bdc1-9cae46f46580).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553561

Chicago Manual of Style (16^th Edition):

Xia, Qingfeng. “Enhancement of liquids mixing using active pulsation in the laminar flow regime.” 2012. Doctoral Dissertation, University of Manchester. Accessed January 18, 2021. https://www.research.manchester.ac.uk/portal/en/theses/enhancement-of-liquids-mixing-using-active-pulsation-in-the-laminar-flow-regime(bcb5ff26-11c4-4301-bdc1-9cae46f46580).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553561.

MLA Handbook (7^th Edition):

Xia, Qingfeng. “Enhancement of liquids mixing using active pulsation in the laminar flow regime.” 2012. Web. 18 Jan 2021.

Vancouver:

Xia Q. Enhancement of liquids mixing using active pulsation in the laminar flow regime. [Internet] [Doctoral dissertation]. University of Manchester; 2012. [cited 2021 Jan 18]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/enhancement-of-liquids-mixing-using-active-pulsation-in-the-laminar-flow-regime(bcb5ff26-11c4-4301-bdc1-9cae46f46580).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553561.

Council of Science Editors:

Xia Q. Enhancement of liquids mixing using active pulsation in the laminar flow regime. [Doctoral Dissertation]. University of Manchester; 2012. Available from: https://www.research.manchester.ac.uk/portal/en/theses/enhancement-of-liquids-mixing-using-active-pulsation-in-the-laminar-flow-regime(bcb5ff26-11c4-4301-bdc1-9cae46f46580).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553561

University of Wollongong

25. Sarwar, Md. Golam Mahabub. Vulnerability assessment of the coast of Bangladesh using geographic information systems.

Degree: Doctor of Philosophy, 2011, University of Wollongong

URL: ; https://ro.uow.edu.au/theses/3825

► The vulnerability of a coast is related to its geomorphic condition, slope status, past shoreline change, rate of relative sea-level rise (SLR), tidal range… (more)

▼ The vulnerability of a coast is related to its geomorphic condition, slope status, past shoreline change, rate of relative sea-level rise (SLR), tidal range and exposure to waves. A Coastal Vulnerability Index (CVI) was developed by Gornitz and Kanciruk in 1989 which has been adopted and modified by subsequent researchers and organizations. The coast of Bangladesh is considered to be one of the most vulnerable in the world, but a thorough assessment of its vulnerability has not been undertaken previously. This study has developed a vulnerability index for the entire coast of the country based on these six physical variables. A total of 957 cells of the coast (excluding river mouths) have been divided into five vulnerability classes for all of the variables except SLR. The SLR variable has been divided into four vulnerability classes. The geomorphology variable has been mapped from satellite imagery to classify the coast into categories such as mud flat, sandy beach, mangrove or cliff. Elevation obtained from SRTM, ASTER and GTOPO datasets has shown contradictory results, indicating overestimated elevation in dense forested areas, especially in the Sundarbans coastal zone. Therefore, slope has been used in preference. The shoreline of the coast has been detected using a band ratio approach to discriminate the water line on Landsat images over a 20- year period from 1989 to 2009. Rates of shoreline change have been calculated using the End Point Rate (EPR) method in the Digital Shoreline Analysis System (DSAS) extension in ArcGIS®. The coast has been observed to be very dynamic with recorded erosion of 285 m/yr and accretion of 633 m/yr. Sea-level rise has been calculated using tide-gauge data indicating high variability along the coast. However, relative sea-level change along the Bangladesh coast is still unclear. Similarly, tidal range obtained from secondary sources has been found to be variable throughout the coast, with the highest tidal range around the Feni River estuary, including Sandwip Island. Although most of the studies have considered wave heights as a variable in the CVI calculation, this study has considered surge height because of the frequent cyclones hitting the coast. Coastal vulnerability indices for the Bangladesh coast have been calculated using four formulae: i) product mean ii) average sum of squares, iii) square means of product mean, and iv) sum of product methods. Additionally, the fourth formula has been modified to explore a more reliable vulnerability measure for the coast. Different formulae have…

Subjects/Keywords: sea-level rise; shoreline change; coastal vulnerability; coastal community; coastal zone of Bangladesh; CVI

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APA (6^th Edition):

Sarwar, M. G. M. (2011). Vulnerability assessment of the coast of Bangladesh using geographic information systems. (Doctoral Dissertation). University of Wollongong. Retrieved from ; https://ro.uow.edu.au/theses/3825

Chicago Manual of Style (16^th Edition):

Sarwar, Md Golam Mahabub. “Vulnerability assessment of the coast of Bangladesh using geographic information systems.” 2011. Doctoral Dissertation, University of Wollongong. Accessed January 18, 2021. ; https://ro.uow.edu.au/theses/3825.

MLA Handbook (7^th Edition):

Sarwar, Md Golam Mahabub. “Vulnerability assessment of the coast of Bangladesh using geographic information systems.” 2011. Web. 18 Jan 2021.

Vancouver:

Sarwar MGM. Vulnerability assessment of the coast of Bangladesh using geographic information systems. [Internet] [Doctoral dissertation]. University of Wollongong; 2011. [cited 2021 Jan 18]. Available from: ; https://ro.uow.edu.au/theses/3825.

Council of Science Editors:

Sarwar MGM. Vulnerability assessment of the coast of Bangladesh using geographic information systems. [Doctoral Dissertation]. University of Wollongong; 2011. Available from: ; https://ro.uow.edu.au/theses/3825

University of Melbourne

26. Bezore, Rhiannon. The morphology and evolution of rock coasts over eustatic cycles in temperate, wave dominated environments.

Degree: 2019, University of Melbourne

URL: http://hdl.handle.net/11343/225681

► Rock coasts comprise 80% of the world’s shorelines and about 50% of the Victorian coast. Their morphology and evolution over time is the result of… (more)

▼ Rock coasts comprise 80% of the world’s shorelines and about 50% of the Victorian coast. Their morphology and evolution over time is the result of marine and subaerial erosional processes that carve features such as sea cliffs, shore platforms, and sea stacks out of the landscape. Rock coasts, therefore, evolve over multiple sea level cycles and create dynamic landscapes on an interglacial timescale. Sea level has risen and fallen over geologic time, with coastal features being formed during sea level high stands. While most coastal landforms found along the modern coast were formed over the past 6,000 years, older coastal features have also been preserved over multiple eustatic cycles, both above and beneath modern sea level. As coastal landforms are formed at or very near sea level, preserved paleo-shoreline features can be used as proxies to reconstruct past sea levels on a regional scale, which had not previously been done for the coast of Victoria, Australia. In this study, an integrated aerial LiDAR and bathymetric multibeam dataset from +20 to -80 m water depth was used to precisely map and quantify the morphology of the rock coast features along the coast of Victoria from Port Fairy in the west to Wilsons Promontory in the east and to analyze the relation between the features’ elevations and the sea levels at which they first formed. This was completed for both the modern coastline as well as paleo-shoreline landforms found 50-60 m below modern sea level, where the offshore geology reflected the onshore geologic units, allowing for an analogous study. These preserved features are believed to have formed during the MIS 3 high stand, during which time sea level most closely matched their average present depths. The culminating results provide not only the first study of the precise morphology of these submerged features in Victoria but also have wider applications for modelling sea level and rocky coast evolution in other temperate, wave dominated environments.

Subjects/Keywords: coastal geology; geomorphology; sea level; rocky coasts; coastal processes; Australia; coastal science

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APA (6^th Edition):

Bezore, R. (2019). The morphology and evolution of rock coasts over eustatic cycles in temperate, wave dominated environments. (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/225681

Chicago Manual of Style (16^th Edition):

Bezore, Rhiannon. “The morphology and evolution of rock coasts over eustatic cycles in temperate, wave dominated environments.” 2019. Doctoral Dissertation, University of Melbourne. Accessed January 18, 2021. http://hdl.handle.net/11343/225681.

MLA Handbook (7^th Edition):

Bezore, Rhiannon. “The morphology and evolution of rock coasts over eustatic cycles in temperate, wave dominated environments.” 2019. Web. 18 Jan 2021.

Vancouver:

Bezore R. The morphology and evolution of rock coasts over eustatic cycles in temperate, wave dominated environments. [Internet] [Doctoral dissertation]. University of Melbourne; 2019. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/11343/225681.

Council of Science Editors:

Bezore R. The morphology and evolution of rock coasts over eustatic cycles in temperate, wave dominated environments. [Doctoral Dissertation]. University of Melbourne; 2019. Available from: http://hdl.handle.net/11343/225681

Texas A&M University

27. Guarriello, Felicia Rose. The Effects of Low-Level Wind Shear Orientation, Depth, and Magnitude on Low-Level Rotation in Simulated Supercell Thunderstorms.

Degree: MS, Atmospheric Sciences, 2016, Texas A&M University

URL: http://hdl.handle.net/1969.1/158140

► Supercell thunderstorms simulated using the numerical model CM1 are used to analyze the effects of low-level vertical wind shear on near-ground rotation in the storm.… (more)

▼ Supercell thunderstorms simulated using the numerical model CM1 are used to analyze the effects of low-level vertical wind shear on near-ground rotation in the storm. In particular, the parameters being assessed are the orientation, magnitude, and depth of the low-level vertical wind shear. Particular emphasis is given to the effects of the shear in determining the position of the low-level outflow relative to the midlevel mesocyclone/updraft. The simulations are initialized using idealized soundings of quarter-circle, clockwise turning, with unidirectional westerly shear above 2 km hodographs. A control simulation is run without any low-level vertical wind shear to compare to the other runs. Experiments are then conducted in which the background sounding is modified by adding a low-level shear layer at one of three different orientation angles: 0° (easterly shear), 90° (southerly shear), or 180° (westerly shear). Comparing a set of simulations run for a shear layer depth of 500 meters with a shear magnitude of 7 m s^−1 , the most favorable orientation for intensifying near-ground rotation based on positioning of the outflow relative to the midlevel mesocyclone was the 0° case. The 90° case became more favorable after being run for another hour, where as the control and 180° cases did not develop favorable conditions. Changing the shear layer depth to 250 meters gives similar results, but when the shear layer depth is changed to 1 kilometer the most favorable simulation became the control. Finally, when the magnitude of the shear was increased to 15 m s^ −1 , none of the cases was found to be favorable, as the outflow was not found to be positioned in any of the simulations below the midlevel mesocyclone. Statistically, a significant negative correlation was found between the maximum near-ground vertical vorticity/circulation and the distance between the maximum near-ground rotation and the midlevel mesocyclone. When this distance decreased, the vertical vorticity/circulation increased, suggesting that the positioning of the outflow beneath the midlevel mesocyclone plays a key role in amplifying the surface rotation. For the particular sounding used in this study, a low-level shear orientation produces the most favorable positioning of the outflow beneath the mesocyclone, and thus lead to the strongest surface rotation among the cases considered. Advisors/Committee Members: Nowotarski, Christopher (advisor), Epifanio, Craig (advisor), Hetland, Robert (committee member).

Subjects/Keywords: low-level shear; supercell

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APA (6^th Edition):

Guarriello, F. R. (2016). The Effects of Low-Level Wind Shear Orientation, Depth, and Magnitude on Low-Level Rotation in Simulated Supercell Thunderstorms. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/158140

Chicago Manual of Style (16^th Edition):

Guarriello, Felicia Rose. “The Effects of Low-Level Wind Shear Orientation, Depth, and Magnitude on Low-Level Rotation in Simulated Supercell Thunderstorms.” 2016. Masters Thesis, Texas A&M University. Accessed January 18, 2021. http://hdl.handle.net/1969.1/158140.

MLA Handbook (7^th Edition):

Guarriello, Felicia Rose. “The Effects of Low-Level Wind Shear Orientation, Depth, and Magnitude on Low-Level Rotation in Simulated Supercell Thunderstorms.” 2016. Web. 18 Jan 2021.

Vancouver:

Guarriello FR. The Effects of Low-Level Wind Shear Orientation, Depth, and Magnitude on Low-Level Rotation in Simulated Supercell Thunderstorms. [Internet] [Masters thesis]. Texas A&M University; 2016. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1969.1/158140.

Council of Science Editors:

Guarriello FR. The Effects of Low-Level Wind Shear Orientation, Depth, and Magnitude on Low-Level Rotation in Simulated Supercell Thunderstorms. [Masters Thesis]. Texas A&M University; 2016. Available from: http://hdl.handle.net/1969.1/158140

University of Illinois – Urbana-Champaign

28. Sun, Zelei. VAST-LP: clock gating in high-level synthesis.

Degree: MS, Electrical & Computer Engr, 2016, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/90970

► High-level synthesis (HLS) promises high-quality hardware with minimal develop- ment e ort. In this thesis, we evaluate the current state-of-the-art HLS engine VAST and propose… (more)

Subjects/Keywords: low power; high level synthesis

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APA (6^th Edition):

Sun, Z. (2016). VAST-LP: clock gating in high-level synthesis. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/90970

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sun, Zelei. “VAST-LP: clock gating in high-level synthesis.” 2016. Thesis, University of Illinois – Urbana-Champaign. Accessed January 18, 2021. http://hdl.handle.net/2142/90970.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sun, Zelei. “VAST-LP: clock gating in high-level synthesis.” 2016. Web. 18 Jan 2021.

Vancouver:

Sun Z. VAST-LP: clock gating in high-level synthesis. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2016. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2142/90970.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sun Z. VAST-LP: clock gating in high-level synthesis. [Thesis]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/90970

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Newcastle

29. Agha Karimi, Armin. Sea level variability and mean sea level determination around Australia from satellite altimetry.

Degree: PhD, 2019, University of Newcastle

URL: http://hdl.handle.net/1959.13/1407551

►

Research Doctorate - Doctor of Philosophy (PhD)

This research aims at studying the sea level variability and determining the Mean Sea Surface (MSS) around Australia… (more)

▼

Research Doctorate - Doctor of Philosophy (PhD)

This research aims at studying the sea level variability and determining the Mean Sea Surface (MSS) around Australia using satellite altimetry data in the period from 1993 to 2018. Analysing sea level variation is of a great importance due to its effects on coastal areas. Particularly, several studies have reported the acceleration in the sea level rise mainly due to the anthropogenic impacts. In this respect, determination of the sea level behaviour at the regional scale gives better understanding about the underlying threats of sea level rise on coastal regions. Accurate determination of the sea level rise around Australia, in the altimetry era, is the one of the main objectives of this study. The usability of the CryoSat-2 data to augment the existing global MSS and derive a new MSS around Australia is also analysed in this dissertation. CryoSat-2 data provides spatially denser and more accurate data in comparison to previous conventional altimetry missions. Fitting a surface to the CryoSat-2 Sea Surface Height (SSH) data may not provide a true MSS due to the presence of strong annual and semi-annual signals in the measured sea level data. A two-stage method is applied to mitigate the effect of periodic and non-periodic signals in the Sea Level Anomalies (SLAs) provided by CryoSat-2. At the first stage, the annual and semi-annual signals are removed using data from Topex/Poseidon and follow on missions. Then, the data are clustered in 0.1° x 0.1° cells and averaged to compensate for the effects of non-periodic signals. The estimated MSS provides promising result when it is compared to the MSS derived from Jason-2 and Jason-3 data, obtained in the same time span of CryoSat-2 data. The Mean Dynamic Topography (MDT) is also estimated using the MSS of CryoSat-2. It gives a consistent result when compared to global MDT models and is in good agreement with geodetic data. Additionally, the north-south tilt of Australian Height Datum (AHD) and the offset between the vertical datum of mainland and Tasmania are re-estimated using the MDT derived from CryoSat-2 data. The results show that the north-south tilt is ~27 mm/degree and the offset between AHD (Tasmania) and AHD (mainland) is highly variable depending on the locations adopted for the estimation of the offset. The sea level trend in the altimetry era is investigated considering the low frequency signals modulated by climate modes in the tropical region around Australia. Two new methods are used to estimate the sea level trend by considering the intra-decadal and decadal signals. The average sea level rise is estimated as 3.92 ± 0.15 mm/year around Australia. Apparently, the sea level rise in the tropical regions approximately doubles that in the Southern Ocean. The intra-decadal and decadal signals are traceable in the effective climate indices in the area. The time-frequency analysis of the signals in both climate indices and altimetry data shows that the intra-decadal signals, except for annual signal, are not…

Advisors/Committee Members: University of Newcastle. Faculty of Engineering & Built Environment, School of Engineering.

Subjects/Keywords: sea level variation; coastal regions; sea level rise; CryoSat

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Agha Karimi, A. (2019). Sea level variability and mean sea level determination around Australia from satellite altimetry. (Doctoral Dissertation). University of Newcastle. Retrieved from http://hdl.handle.net/1959.13/1407551

Chicago Manual of Style (16^th Edition):

Agha Karimi, Armin. “Sea level variability and mean sea level determination around Australia from satellite altimetry.” 2019. Doctoral Dissertation, University of Newcastle. Accessed January 18, 2021. http://hdl.handle.net/1959.13/1407551.

MLA Handbook (7^th Edition):

Agha Karimi, Armin. “Sea level variability and mean sea level determination around Australia from satellite altimetry.” 2019. Web. 18 Jan 2021.

Vancouver:

Agha Karimi A. Sea level variability and mean sea level determination around Australia from satellite altimetry. [Internet] [Doctoral dissertation]. University of Newcastle; 2019. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1959.13/1407551.

Council of Science Editors:

Agha Karimi A. Sea level variability and mean sea level determination around Australia from satellite altimetry. [Doctoral Dissertation]. University of Newcastle; 2019. Available from: http://hdl.handle.net/1959.13/1407551

University of Waikato

30. Harrison, Shawn Robert. Morphodynamics of Ebb-Tidal Deltas .

Degree: 2015, University of Waikato

URL: http://hdl.handle.net/10289/9810

► The purpose of this study was to learn more about the significant drivers of ebb-tidal delta morphology using observational methods and fundamental physical relationships between… (more)

▼ The purpose of this study was to learn more about the significant drivers of ebb-tidal delta morphology using observational methods and fundamental physical relationships between forcing conditions and morphological response. Two techniques were adapted in a novel way to study the dynamics of geomorphic features at an ebb-tidal delta. A 5-year long record of video imagery was used to observe a natural mixed-energy ebb-tidal delta in the field. A semi-analytical ebb-jet model, which was coupled to an exploratory morphological model, was developed and used to explore the interactions between tidal currents, waves, and morphology, and to test the sensitivity of morphological development and response to changes in forcing conditions. A detailed video-based observational record was used to identify and track geomorphic features over 5 years at an ebb-tidal delta on the energetic west coast of New Zealand at Raglan by using depth-limited wave-breaking patterns as a proxy for the position of shallow sandbars. Oblique 20-minute averaged time-exposure images were geo-rectified to provide detailed spatial measurements of ebb-tidal delta features such as the terminal lobe, mouth bar, channel margin linear bars (or levees), and swash bars over the 5-year duration. Movements of these features were quantified and related to wave and tidal forcing, including seasonal and interannual trends in wave climate. In general, the low-energy restorative summer waves led to a more cuspate terminal lobe, while in the high-energy erosive winter waves straightened the terminal lobe and moved it further seaward than the long-term average. Movements throughout the delta were intermittent between less active periods, with the fastest swash bar migrations occurring during the transition between seasons, namely winter to spring and summer to autumn. A semi-analytical model for ebbing tidal jet flow was developed based on the balance of momentum between inertia, bed friction, turbulent mixing, and wave effects. Previous analytical jet models (Özsoy and Ünlüata, 1982; Joshi, 1982) were extended to include the effects of directly opposing breaking waves. The model was calibrated and compared with scaled laboratory measurements (Ismail and Wiegel, 1983) and numerical simulations (Nardin et al., 2013) of river jets flowing over flat bathymetry with non-breaking waves, and with detailed field measurements of jet flow and wave dissipation at New River Inlet, North Carolina (e.g. Wargula et al., 2014). The jet model demonstrated the influence of opposing breaking waves on ebb-jet currents and jet width, along with the emergence of a point of flow convergence. The contribution of wave effects to the momentum balance were shown to impact the rapid slowing of jet flow, overall extent of an ebb-jet, and increase the jet width agreeing with previous studies (Nardin and Fagherazzi 2012; Nardin et al., 2013; Olabarrietta et al., 2014). Using a channelization parameter to emulate the ability of channel levees to constrain jet spreading, the model was calibrated… Advisors/Committee Members: Bryan, Karin R (advisor), Mullarney, Julia C (advisor), de Lange, Willem P (advisor), Winter, Christian (advisor).

Subjects/Keywords: Ebb-tidal delta; jet model; coastal morphodynamics; Raglan; photogrammetry

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Harrison, S. R. (2015). Morphodynamics of Ebb-Tidal Deltas . (Doctoral Dissertation). University of Waikato. Retrieved from http://hdl.handle.net/10289/9810

Chicago Manual of Style (16^th Edition):

Harrison, Shawn Robert. “Morphodynamics of Ebb-Tidal Deltas .” 2015. Doctoral Dissertation, University of Waikato. Accessed January 18, 2021. http://hdl.handle.net/10289/9810.

MLA Handbook (7^th Edition):

Harrison, Shawn Robert. “Morphodynamics of Ebb-Tidal Deltas .” 2015. Web. 18 Jan 2021.

Vancouver:

Harrison SR. Morphodynamics of Ebb-Tidal Deltas . [Internet] [Doctoral dissertation]. University of Waikato; 2015. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10289/9810.

Council of Science Editors:

Harrison SR. Morphodynamics of Ebb-Tidal Deltas . [Doctoral Dissertation]. University of Waikato; 2015. Available from: http://hdl.handle.net/10289/9810

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Open Access Theses and Dissertations