+publisher:"Colorado State University" +contributor:("Cotton, William R.")

Colorado State University

1. Samman, Ahmad. Numerical simulation diagnostics of a flash flood event in Jeddah, Saudi Arabia.

Degree: MS(M.S.), Atmospheric Science, 2014, Colorado State University

► On 26 January 2011, a severe storm hit the city of Jeddah, the second largest city in the Kingdom of Saudi Arabia. The storm resulted… (more)

▼ On 26 January 2011, a severe storm hit the city of Jeddah, the second largest city in the Kingdom of Saudi Arabia. The storm resulted in heavy rainfall, which produced a flash flood in a short period of time. This event caused at least eleven fatalities and more than 114 injuries. Unfortunately, the observed rainfall data are limited to the weather station at King Abdul Aziz International airport, which is north of the city, while the most extreme precipitation occurred over the southern part of the city. This observation was useful to compare simulation result even though it does not reflect the severity of the event. The Regional Atmospheric Modeling System (RAMS) developed at Colorado State University was used to study this storm event. RAMS simulations indicted that a quasi-stationary Mesoscale convective system developed over the city of Jeddah and lasted for several hours. It was the source of the huge amount of rainfall. The model computed a total rainfall of more than 110 mm in the southern part of the city, where the flash flood occurred. This precipitation estimation was confirmed by the actual observation of the weather radar. While the annual rainfall in Jeddah during the winter varies from 50 to 100 mm, the amount of the rainfall resulting from this storm event exceeded the climatological total annual rainfall. The simulation of this event showed that warm sea surface temperature, combined with high humidity in the lower atmosphere and a large amount of convective available potential energy (CAPE) provided a favorable environment for convection. It also showed the presence of a cyclonic system over the north and eastern parts of the Mediterranean Sea, and a subtropical anti-cyclone over Northeastern Africa that contributed to cold air advection bringing cold air to the Jeddah area. In addition, an anti-cyclone (blocking) centered over east and southeastern parts of the Arabian Peninsula and the Arabian Sea produced a low level jet over the southern part of the Red Sea, which transported large water vapor amounts over Jeddah. The simulation results showed that the main driver behind the storm was the interaction between these systems over the city of Jeddah (an urban heat island) that produced strong low-level convergence. Several sensitivity experiments were carried out showed that other variables could have contributed to storm severity as well. Those sensitivity experiments included several simulations in which the following variables were changed: physiographic properties were altered by removing the water surfaces, removing the urban heat island environment from the model, and changing the concentration of cloud condensation nuclei. The results of these sensitivity experiments showed that these properties have significant effects on the storm formation and severity. Advisors/Committee Members: Cotton, William R. (advisor), Schumacher, Russ (committee member), Fontane, Darrell G. (committee member).

Subjects/Keywords: extreme precipitation; Saudi Arabia; Jeddah; flash floods

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Samman, A. (2014). Numerical simulation diagnostics of a flash flood event in Jeddah, Saudi Arabia. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/82532

Chicago Manual of Style (16^th Edition):

Samman, Ahmad. “Numerical simulation diagnostics of a flash flood event in Jeddah, Saudi Arabia.” 2014. Masters Thesis, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/82532.

MLA Handbook (7^th Edition):

Samman, Ahmad. “Numerical simulation diagnostics of a flash flood event in Jeddah, Saudi Arabia.” 2014. Web. 07 Mar 2021.

Vancouver:

Samman A. Numerical simulation diagnostics of a flash flood event in Jeddah, Saudi Arabia. [Internet] [Masters thesis]. Colorado State University; 2014. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/82532.

Council of Science Editors:

Samman A. Numerical simulation diagnostics of a flash flood event in Jeddah, Saudi Arabia. [Masters Thesis]. Colorado State University; 2014. Available from: http://hdl.handle.net/10217/82532

Colorado State University

2. Loftus, Adrian Matthew. Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A.

Degree: PhD, Atmospheric Science, 2012, Colorado State University

URL: http://hdl.handle.net/10217/67571

► Hail is a frequent occurrence in warm season deep convection in many mid-latitude regions and causes significant damage to property and agricultural interests every year.… (more)

▼ Hail is a frequent occurrence in warm season deep convection in many mid-latitude regions and causes significant damage to property and agricultural interests every year. Hail can also have a substantial impact on the precipitation characteristics of deep convection as well as on the dynamic and thermodynamic properties of convective downdrafts and cold-pools, which in turn can affect storm evolution and propagation. In addition, large and often destructive hail commonly occurs in severe convection, yet most one- (1M) and two-moment (2M) bulk microphysics schemes in cloud-resolving numerical models are incapable of producing large hail (diameter D ≥ 2 cm). The limits imposed by fixing one or two of the distribution parameters in these schemes often lead to particularly poor representations of particles within the tails of size distribution spectra; an especially important consideration for hail, which covers a broad range of sizes in nature. In order to improve the representation of hail distributions in simulations of deep moist convection in a cloud-resolving numerical model, a new triple-moment bulk hail microphysics scheme (3MHAIL) is presented and evaluated. The 3MHAIL scheme predicts the relative dispersion parameter for a gamma distribution function via the prediction of the sixth moment (related to the reflectivity factor) of the distribution in addition to the mass mixing ratio and number concentration (third and zeroeth moments, respectively) thereby allowing for a fully prognostic distribution function. Initial testing of this scheme reveals significant improvement in the representation of sedimentation, melting, and formation processes of hail compared to lower-order moment schemes. The 3MHAIL scheme is verified in simulations of a well-observed supercell storm that occurred over northwest Kansas on 29 June 2000 during the Severe Thunderstorm and Electrification and Precipitation Study (STEPS). Comparisons of the simulation results with the observations for this case, as well as with results of simulations using two different 2M microphysics schemes, suggest a significant improvement of the simulated storm structure and evolution is achieved with the 3MHAIL scheme. The generation of large hail and subsequent fallout in the simulation using 3MHAIL microphysics show particularly good agreement with surface hail reports for this storm as well as with previous studies of hail in supercell storms. On the other hand, the simulation with 2M microphysics produces only small hail aloft and virtually no hail at the surface, whereas a two-moment version of the 3MHAIL scheme (with a fixed relative dispersion parameter) produces unrealistically high amounts of large hail at low levels as a result of artificial shifts in the hail size spectra towards larger diameter hail during the melting process. The 3MHAIL scheme is also used to investigate the impact of changing the concentrations of aerosols that act as cloud condensation nuclei (CCN) on hail for the 29 June 2000 supercell case. For the simulated supercells in the… Advisors/Committee Members: Cotton, William R. (advisor), Rutledge, Steven A. (committee member), van den Heever, Susan C. (committee member), Bringi, Viswanathan N. (committee member).

Subjects/Keywords: aerosols; convection; hail; microphysics; numerical model; supercell

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Loftus, A. M. (2012). Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/67571

Chicago Manual of Style (16^th Edition):

Loftus, Adrian Matthew. “Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A.” 2012. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/67571.

MLA Handbook (7^th Edition):

Loftus, Adrian Matthew. “Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A.” 2012. Web. 07 Mar 2021.

Vancouver:

Loftus AM. Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A. [Internet] [Doctoral dissertation]. Colorado State University; 2012. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/67571.

Council of Science Editors:

Loftus AM. Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A. [Doctoral Dissertation]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/67571

Colorado State University

3. Wang, Fang. Quantitative comparisons of satellite observations and cloud models.

Degree: PhD, Atmospheric Science, 2011, Colorado State University

URL: http://hdl.handle.net/10217/52115

► Microwave radiation interacts directly with precipitating particles and can therefore be used to compare microphysical properties found in models with those found in nature. Lower… (more)

▼ Microwave radiation interacts directly with precipitating particles and can therefore be used to compare microphysical properties found in models with those found in nature. Lower frequencies (< 37 GHz) can detect the emission signals from the raining clouds over radiometrically cold ocean surfaces while higher frequencies (≥ 37 GHz) are more sensitive to the scattering of the precipitating-sized ice particles in the convective storms over high-emissivity land, which lend them particular capabilities for different applications. Both are explored with a different scenario for each case: a comparison of two rainfall retrievals over ocean and a comparison of a cloud model simulation to satellite observations over land. Both the Goddard Profiling algorithm (GPROF) and European Centre for Medium-Range Weather Forecasts (ECMWF) one-dimensional + four-dimensional variational analysis (1D+4D-Var) rainfall retrievals are inversion algorithms based on the Bayes' theorem. Differences stem primarily from the a-priori information. GPROF uses an observationally generated a-priori database while ECMWF 1D-Var uses the model forecast First Guess (FG) fields. The relative similarity in the two approaches means that comparisons can shed light on the differences that are produced by the a-priori information. Case studies have found that differences can be classified into four categories based upon the agreement in the brightness temperatures (Tbs) and in the microphysical properties of Cloud Water Path (CWP) and Rain Water Path (RWP) space. We found a category of special interest in which both retrievals converge to similar Tb through minimization procedures but produce different CWP and RWP. The similarity in Tb can be attributed to comparable Total Water Path (TWP) between the two retrievals while the disagreement in the microphysics is caused by their different degrees of constraint of the cloud/rain ratio by the observations. This situation occurs frequently and takes up 46.9% in the one month 1D-Var retrievals examined. To attain better constrained cloud/rain ratios and improved retrieval quality, this study suggests the implementation of higher microwave frequency channels in the 1D-Var algorithm. Cloud Resolving Models (CRMs) offer an important pathway to interpret satellite observations of microphysical properties of storms. High frequency microwave brightness temperatures (Tbs) respond to precipitating-sized ice particles and can, therefore, be compared with simulated Tbs at the same frequencies. By clustering the Tb vectors at these frequencies, the scene can be classified into distinct microphysical regimes, in other words, cloud types. The properties for each cloud type in the simulated scene are compared to those in the observation scene to identify the discrepancies in microphysics within that cloud type. A convective storm over the Amazon observed by the Tropical Rainfall Measuring Mission (TRMM) is simulated using the Regional Atmospheric Modeling System (RAMS) in a semi-ideal setting, and four regimes are defined… Advisors/Committee Members: Kummerow, Christian D. (advisor), Vonder Haar, Thomas H. (committee member), Cotton, William R. (committee member), Ramirez, Jorge A. (committee member).

Subjects/Keywords: cloud microphysics; rainfall retrieval; microwave remote sensing

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Wang, F. (2011). Quantitative comparisons of satellite observations and cloud models. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/52115

Chicago Manual of Style (16^th Edition):

Wang, Fang. “Quantitative comparisons of satellite observations and cloud models.” 2011. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/52115.

MLA Handbook (7^th Edition):

Wang, Fang. “Quantitative comparisons of satellite observations and cloud models.” 2011. Web. 07 Mar 2021.

Vancouver:

Wang F. Quantitative comparisons of satellite observations and cloud models. [Internet] [Doctoral dissertation]. Colorado State University; 2011. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/52115.

Council of Science Editors:

Wang F. Quantitative comparisons of satellite observations and cloud models. [Doctoral Dissertation]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/52115

Colorado State University

4. Lerach, David Gregory. Simulating southwestern U.S. desert dust influences on severe, tornadic storms.

Degree: PhD, Atmospheric Science, 2012, Colorado State University

URL: http://hdl.handle.net/10217/67575

► In this study, three-dimensional numerical simulations were performed using the Regional Atmospheric Modeling System (RAMS) model to investigate possible southwestern U.S. desert dust impacts on… (more)

▼ In this study, three-dimensional numerical simulations were performed using the Regional Atmospheric Modeling System (RAMS) model to investigate possible southwestern U.S. desert dust impacts on severe, tornadic storms. Initially, two sets of simulations were conducted for an idealized supercell thunderstorm. In the first set, two numerical simulations were performed to assess the impacts of increased aerosol concentrations acting as cloud condensation nuclei (CCN) and giant CCN (GCCN). Initial profiles of CCN and GCCN concentrations were set to represent "clean" continental and aerosol-polluted environments, respectively. With a reduction in warm- and cold-rain processes, the polluted environment produced a longer-lived supercell with a well-defined rear flank downdraft (RFD) and relatively weak forward flank downdraft (FFD) that produced weak evaporative cooling, a weak cold-pool, and an EF-1 tornado. The clean environment produced no tornado and was less favorable for tornadogenesis. In the second ensemble, aerosol microphysical effects were put into context with those of convective available potential energy (CAPE) and low-level moisture. Simulations initialized with greater low-level moisture and higher CAPE produced significantly stronger precipitation, which resulted in greater evaporation and associated cooling, thus producing stronger cold-pools at the surface associated with both the forward- and rear-flank downdrafts. Simulations initialized with higher CCN concentrations resulted in reduced warm rain and more supercooled water aloft, creating larger anvils with less ice mass available for precipitation. These simulated supercells underwent less evaporative cooling within downdrafts and produced weaker cold-pools compared to the lower CCN simulations. Tornadogenesis was related to the size, strength, and location of the FFD- and RFD-based cold-pools. The combined influence of low-level moisture and CAPE played a considerably larger role on tornadogenesis compared to aerosol impacts. However, the aerosol effect was still evident. In both idealized model ensembles, the strongest, longest-lived tornado-like vortices were associated with warmer and weaker cold-pools, higher CAPE, and less negative buoyancy in the near-vortex environment compared to those storms that produced shorter-lived, weaker vortices. A final set of nested grid simulations were performed to evaluate dust indirect microphysical and direct radiative impacts on a severe storms outbreak that occurred during 15-16 April 2003 in Texas and Oklahoma. In one simulation, neither dust microphysical nor radiative effects were included (CTL). In a second simulation, only dust radiative effects were considered (RAD). In a third simulation, both dust radiative and indirect microphysical effects were simulated (DST), where dust was allowed to serve as CCN, GCCN, and ice nuclei (IN). Fine mode dust serving as CCN reduced warm rain formation in the DST simulation. Thus, cloud droplets were transported into the mixed phase region, enhancing… Advisors/Committee Members: Cotton, William R. (advisor), Rutledge, Steven A. (committee member), Kreidenweis, Sonia M. (committee member), Roesner, Larry A. (committee member).

Subjects/Keywords: aerosol; tornadoes; supercells; dust

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Lerach, D. G. (2012). Simulating southwestern U.S. desert dust influences on severe, tornadic storms. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/67575

Chicago Manual of Style (16^th Edition):

Lerach, David Gregory. “Simulating southwestern U.S. desert dust influences on severe, tornadic storms.” 2012. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/67575.

MLA Handbook (7^th Edition):

Lerach, David Gregory. “Simulating southwestern U.S. desert dust influences on severe, tornadic storms.” 2012. Web. 07 Mar 2021.

Vancouver:

Lerach DG. Simulating southwestern U.S. desert dust influences on severe, tornadic storms. [Internet] [Doctoral dissertation]. Colorado State University; 2012. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/67575.

Council of Science Editors:

Lerach DG. Simulating southwestern U.S. desert dust influences on severe, tornadic storms. [Doctoral Dissertation]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/67575

Colorado State University

5. Wood, Norman Bryce. Estimation of snow microphysical properties with application to millimeter-wavelength radar retrievals for snowfall rate.

Degree: PhD, Atmospheric Science, 2011, Colorado State University

URL: http://hdl.handle.net/10217/48170

► The need for measuring snowfall is driven by the roles snow plays providing freshwater resources and affecting climate. Snow accumulations are an important resource for… (more)

▼ The need for measuring snowfall is driven by the roles snow plays providing freshwater resources and affecting climate. Snow accumulations are an important resource for ecological and human needs and in many areas appear vulnerable to climate change. Snow cover modifies surface heat fluxes over areas extensive enough to influence climate at regional and perhaps global scales. Seasonal runoff from snowmelt, along with over-ocean snowfall, contributes to freshening in the Arctic and high-latitude North Atlantic oceans. Yet much of the Earth's area for which snowfall plays such significant roles is not well-monitored by observations. Radar reflectivity at 94 GHz is sensitive to scattering by snow particles and CloudSat, in a near-polar orbit, provides vertically resolved measurements of 94 GHz reflectivity at latitudes from 82 N to 82 S. While not global in areal coverage, CloudSat does provide observations sampled from regions where snowfall is the dominant form of precipitation and an important component of hydrologic processes. The work presented in this study seeks to exploit these observations by developing and assessing a physically-base snowfall retrieval which uses an explicit representation of snow microphysical properties. As the reflectivity-based snowfall retrieval problem is significantly underconstrained, a priori information about snow microphysical properties is required. The approaches typically used to develop relations between reflectivity and snowfall rate, so-called Ze-S relations, require assumptions about particle properties such as mass, area, fallspeed, and shape. Limited information about the distributions of these properties makes difficult the characterization of how uncertainties in the properties influence uncertainties in the Ze-S relations. To address this, the study proceeded in two parts. In the first, probability distributions for snow particle microphysical properties were assessed using optimal estimation applied to multi-sensor surface-based snow observations from a field campaign. Mass properties were moderately well determined by the observations, the area properties less so. The retrieval revealed nontrivial correlations between mass and area parameters not apparent in prior studies. Synthetic testing showed that the performance of the retrieval was hampered by uncertainties in the fallspeed forward model. The mass and area properties obtained from this retrieval were used to construct particle models including 94 GHz scattering properties for dry snow. These properties were insufficient to constrain scattering properties to match observed 94 GHz reflectivities. Vertical aspect ratio supplied a sufficient additional constraint. In the second part, the CloudSat retrieval, designed to estimate vertical profiles of snow size distribution parameters from reflectivity profiles, was applied to measurements from the field campaign and from an orbit of CloudSat observations. Uncertainties in the mass and area microphysical… Advisors/Committee Members: Stephens, Graeme L. (advisor), Cotton, William R. (committee member), Fassnacht, Steven R. (committee member), Kummerow, Christian D. (committee member), Matrosov, Sergey Y. (committee member).

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Wood, N. B. (2011). Estimation of snow microphysical properties with application to millimeter-wavelength radar retrievals for snowfall rate. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/48170

Chicago Manual of Style (16^th Edition):

Wood, Norman Bryce. “Estimation of snow microphysical properties with application to millimeter-wavelength radar retrievals for snowfall rate.” 2011. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/48170.

MLA Handbook (7^th Edition):

Wood, Norman Bryce. “Estimation of snow microphysical properties with application to millimeter-wavelength radar retrievals for snowfall rate.” 2011. Web. 07 Mar 2021.

Vancouver:

Wood NB. Estimation of snow microphysical properties with application to millimeter-wavelength radar retrievals for snowfall rate. [Internet] [Doctoral dissertation]. Colorado State University; 2011. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/48170.

Council of Science Editors:

Wood NB. Estimation of snow microphysical properties with application to millimeter-wavelength radar retrievals for snowfall rate. [Doctoral Dissertation]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/48170

Colorado State University

6. Clavner, Michal. Response of a simulated mesoscale convective system to increased aerosol pollution, The.

Degree: PhD, Atmospheric Science, 2016, Colorado State University

URL: http://hdl.handle.net/10217/173358

► Mesoscale Convective Systems (MCSs) are important contributors to rainfall in the High Plains of the United States and elsewhere in the world. MCSs are also… (more)

▼ Mesoscale Convective Systems (MCSs) are important contributors to rainfall in the High Plains of the United States and elsewhere in the world. MCSs are also producers of severe weather such as hail, tornados and wide-spread straight-line wind events known as derechos. It is therefore of interest to understand how different aerosols serving as cloud condensation nuclei (CCN) concentrations may impact these systems. This work focuses on the impacts of aerosols on the total precipitation amount, rates and spatial distribution of precipitation produced by an MCS, as well as the characteristics of a derecho event. Past studies have shown that the impacts on MCS-produced precipitation to changes in aerosol concentration are strongly dependent on environmental conditions, primarily humidity and environmental wind shear. Changes in aerosol concentrations were found to alter MCS-precipitation production directly by modifying precipitation processes and indirectly by affecting the efficiency of the storm’s self-propagation. Observational and numerical studies have been conducted that have examined the dynamics responsible for the generation of widespread convectively-induced windstorms, primarily focusing on environmental conditions and the MCS features that generate a derecho event. While the sensitivity of the formation of bow-echoes, the radar signature associated with derecho events, to changes in microphysics has been examined, a study on a derecho-producing MCS characteristics to aerosol concentrations has not. In this study different aerosol concentrations and their effects on precipitation and a derecho produced by an MCS are examined by simulating the 8 May 2009 “Super-Derecho” MCS. The MCS was simulated using the Regional Atmospheric Modeling System (RAMS), a cloud-resolving model (CRM) with sophisticated aerosol and microphysical parameterizations. Three simulations were conducted that varied in their initial aerosol concentration, distribution and hygroscopicity as determined by their emission sources. The first simulation contained aerosols from only natural sources and the second with aerosols sourced from both natural and anthropogenic emissions The third simulation contained the same aerosol distribution as in the second simulation, however multiplied by a factor of 5 in order to represent a highly polluted scenario. In all three of the simulations aerosol concentrations were derived from the output of GEOS-Chem, a 3D chemical transport model. In the simulated MCS, the formation and propagation of the storm was not fundamentally modified by changes in the aerosol concentration, and the total MCS-produced precipitation was not significantly affected. However, the precipitation distribution (convective vs stratiform) and derecho-strength surface wind characteristics did vary among the simulations. The more polluted simulations exhibited higher precipitation rates, higher bulk precipitation efficiency, a larger area with heavier convective precipitation and a smaller area with lighter stratiform precipitation.… Advisors/Committee Members: Cotton, William R. (advisor), van den Heever, Susan C. (advisor), Kreidenweis, Sonia M. (committee member), Reising, Steven C. (committee member), Birner, Thomas (committee member).

Subjects/Keywords: derecho; mesoscale convective system; RAMS; increased pollution; aerosol indirect effects; numerical analysis

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Clavner, M. (2016). Response of a simulated mesoscale convective system to increased aerosol pollution, The. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/173358

Chicago Manual of Style (16^th Edition):

Clavner, Michal. “Response of a simulated mesoscale convective system to increased aerosol pollution, The.” 2016. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/173358.

MLA Handbook (7^th Edition):

Clavner, Michal. “Response of a simulated mesoscale convective system to increased aerosol pollution, The.” 2016. Web. 07 Mar 2021.

Vancouver:

Clavner M. Response of a simulated mesoscale convective system to increased aerosol pollution, The. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/173358.

Council of Science Editors:

Clavner M. Response of a simulated mesoscale convective system to increased aerosol pollution, The. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/173358

7. Stephens, Mark Argyle. Simple ice phase parameterization, A.

Degree: MS(M.S.), Atmospheric Science, 1979, Colorado State University

URL: http://hdl.handle.net/10217/178746

► A two variable ice parameterization was developed for use in three dimensional models of cumulonimbus clouds and mesoscale squall lines. Bulk water techniques were employed… (more)

Subjects/Keywords: Ice crystals; Cumulonimbus

1 more image…

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Stephens, M. A. (1979). Simple ice phase parameterization, A. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/178746

Chicago Manual of Style (16^th Edition):

Stephens, Mark Argyle. “Simple ice phase parameterization, A.” 1979. Masters Thesis, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/178746.

MLA Handbook (7^th Edition):

Stephens, Mark Argyle. “Simple ice phase parameterization, A.” 1979. Web. 07 Mar 2021.

Vancouver:

Stephens MA. Simple ice phase parameterization, A. [Internet] [Masters thesis]. Colorado State University; 1979. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/178746.

Council of Science Editors:

Stephens MA. Simple ice phase parameterization, A. [Masters Thesis]. Colorado State University; 1979. Available from: http://hdl.handle.net/10217/178746

8. Jha, Vandana. Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin.

Degree: PhD, Atmospheric Science, 2016, Colorado State University

URL: http://hdl.handle.net/10217/173399

► In this study we examine the cumulative effect of dust acting as cloud nucleating aerosol (cloud condensation nuclei (CCN), giant cloud condensation nuclei (GCCN), and… (more)

▼ In this study we examine the cumulative effect of dust acting as cloud nucleating aerosol (cloud condensation nuclei (CCN), giant cloud condensation nuclei (GCCN), and ice nuclei (IN)) along with anthropogenic aerosol pollution acting primarily as CCN, over the entire Colorado Rocky Mountains from the months of October to April in the year 2004-2005; the snow year. This ~6.5 months analysis provides a range of snowfall totals and variability in dust and anthropogenic aerosol pollution. The specific objectives of this research is to quantify the impacts of both dust and pollution aerosols on wintertime precipitation in the Colorado Mountains using the Regional Atmospheric Modeling System (RAMS). In general, dust enhances precipitation primarily by acting as IN, while aerosol pollution reduces water resources in the CRB via the so-called “spill-over” effect, by enhancing cloud droplet concentrations and reducing riming rates. Dust is more episodic and aerosol pollution is more pervasive throughout the winter season. Combined response to dust and aerosol pollution is a net reduction of water resources in the CRB. The question is by how much are those water resources affected? Our best estimate is that total winter-season precipitation loss for for the CRB the 2004-2005 winter season due to the combined influence of aerosol pollution and dust is 5,380,00 acre-feet of water. Sensitivity studies for different cases have also been run for the specific cases in 2004-2005 winter season to analyze the impact of changing dust and aerosol ratios on precipitation in the Colorado River Basin. The dust is varied from 3 to 10 times in the experiments and the response is found to be non monotonic and depends on various environmental factors. The sensitivity studies show that adding dust in a wet system increases precipitation when IN affects are dominant. For a relatively dry system high concentrations of dust can result in over-seeding the clouds and reductions in precipitation. However, when adding dust to a system with warmer cloud bases, the response is non-monotonical, and when CCN affects are dominant, reductions in precipitation are found. Advisors/Committee Members: Cotton, William R. (advisor), Rutledge, Steven A. (committee member), Pierce, Jeffery (committee member), Ramirez, Jorge (committee member).

Subjects/Keywords: CCN; dust; precipitation; Colorado River Basin; aerosol; IN

…Carrio, Colorado State University from an ensemble of simulations covering a range of vertical… …18 2.4.0 RAMS dynamic model setup In this study we set up the Colorado State University… …been added to read dust into RAMS. Dr. Jeffery Pierce of Colorado State University ran GEOS…

11 more images…

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Jha, V. (2016). Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/173399

Chicago Manual of Style (16^th Edition):

Jha, Vandana. “Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin.” 2016. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/173399.

MLA Handbook (7^th Edition):

Jha, Vandana. “Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin.” 2016. Web. 07 Mar 2021.

Vancouver:

Jha V. Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/173399.

Council of Science Editors:

Jha V. Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/173399

9. Mulvey, G. (Gerald). Physical mechanisms of extra area effects from weather modification.

Degree: PhD, Atmospheric Science, 1977, Colorado State University

URL: http://hdl.handle.net/10217/178712

► One of the complexities of weather modification, namely extra area effects have long posed an opportunity for the long-term control of the earth's weather. This… (more)

▼ One of the complexities of weather modification, namely extra area effects have long posed an opportunity for the long-term control of the earth's weather. This study investigates the physical mechanisms by which cloud seeding projects may cause extra area effects. The investigations center on one of the simplest of precipitating systems, namely the cold wintertime orographic clouds of the central Rocky Mountains. Three lines of investigation are followed: (1) field studies of seeding material movement in the atmosphere and receiver cloud characteristics, (2) numerical simulation, and (3) historical studies of the affected cloud system. The field observations consist of case studies of the movement and dispersion of silver iodide from ground based generators. These studies, during the winters of 1974-75 and 1975-76, used nuclei counters aboard two aircraft. Aerosol silver concentration measurements were also made during the last experimental year. The surface observations made as part of the field studies included snow collection for silver analysis, radar observation and ice nuclei measurements. The aircraft studies established the fact that regions of above background ice nuclei concentrations extend from the target cloud systems as far as 240 km downwind while exhibiting concentrations from 10 to over 700 ice nuclei per liter active at -20°C. The analysis of silver concentrations in snow confirmed above background silver concentrations exist in snow samples on days during which cloud seeding occurred in the mountains. The numerical cloud models were used to investigate the mode of seeding and the seeding requirements of the downwind cloud systems. Case study r n s using a cumulus model suggested that seeding the upslope cloud would cause little dynamic intensification. It was therefore inferred that the seeding mode was static. The second cloud model, a rapid glaciation model, estimated the seeding requirements in terms of active ice nuclei or ice crystals for precipitation augmentation to be between 1.0 and 5 No1-1. An ice crystal transport model was used to predict 0 the survival time for a spectrum of crystal sizes under a variety of conditions. The results indicate that under certain meteorological conditions crystals typically observed in orographic conditions can survive long enough to reach the downwind upslope cloud in concentrations between 0.5 and 50 No1-1. The historical studies established characteristics of the typical upslope clouds as well as the surf ace features controlling their formation. The radar observations showed convective-like echoes migrating within the upslope cloud over the eastern plains of Colorado downwind of Climax. These studies show that at least two feasible mechanisms through which mountain orographic clouds can affect the precipitation on the eastern plains exist, and, under certain conditions, are operative. Advisors/Committee Members: Grant, Lewis O. (advisor), Karaki, Susumu (committee member), Corrin, Myron L. (committee member), Mielke, Paul W. (committee member), Cotton, William R. (committee member).

Subjects/Keywords: Weather control – Colorado

11 more images…

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Mulvey, G. (. (1977). Physical mechanisms of extra area effects from weather modification. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/178712

Chicago Manual of Style (16^th Edition):

Mulvey, G (Gerald). “Physical mechanisms of extra area effects from weather modification.” 1977. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/178712.

MLA Handbook (7^th Edition):

Mulvey, G (Gerald). “Physical mechanisms of extra area effects from weather modification.” 1977. Web. 07 Mar 2021.

Vancouver:

Mulvey G(. Physical mechanisms of extra area effects from weather modification. [Internet] [Doctoral dissertation]. Colorado State University; 1977. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/178712.

Council of Science Editors:

Mulvey G(. Physical mechanisms of extra area effects from weather modification. [Doctoral Dissertation]. Colorado State University; 1977. Available from: http://hdl.handle.net/10217/178712

Colorado State University

10. Kalb, Christina P. Cloud-to-ground lightning polarity and environmental conditions over the central United States.

Degree: MS(M.S.), Atmospheric Science, 2007, Colorado State University

URL: http://hdl.handle.net/10217/178749

► The majority of cloud-to-ground (CG) lightning across the United States lowers negative charge to the ground. However, recent studies have documented storms that produce an… (more)

Subjects/Keywords: Lightning – United States – Analysis; Thunderstorms – United States – Analysis

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Kalb, C. P. (2007). Cloud-to-ground lightning polarity and environmental conditions over the central United States. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/178749

Chicago Manual of Style (16^th Edition):

Kalb, Christina P. “Cloud-to-ground lightning polarity and environmental conditions over the central United States.” 2007. Masters Thesis, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/178749.

MLA Handbook (7^th Edition):

Kalb, Christina P. “Cloud-to-ground lightning polarity and environmental conditions over the central United States.” 2007. Web. 07 Mar 2021.

Vancouver:

Kalb CP. Cloud-to-ground lightning polarity and environmental conditions over the central United States. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/178749.

Council of Science Editors:

Kalb CP. Cloud-to-ground lightning polarity and environmental conditions over the central United States. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/178749

Colorado State University

11. Krall, Geoffrey Michael. Potential indirect effects of aerosol on tropical cyclone development.

Degree: MS(M.S.), Atmospheric Science, 2010, Colorado State University

URL: http://hdl.handle.net/10217/44964

► Observational and model evidence suggest that a 2008 Western Pacific typhoon (NURI) came into contact with and ingested elevated concentrations of aerosol as it neared… (more)

▼ Observational and model evidence suggest that a 2008 Western Pacific typhoon (NURI) came into contact with and ingested elevated concentrations of aerosol as it neared the Chinese coast. This study uses a regional model with two-moment bin emulating microphysics to simulate the typhoon as it enters the field of elevated aerosol concentration. A continental field of cloud condensation nuclei (CCN) was prescribed based on satellite and global aerosol model output, then increased for further sensitivity tests. The typhoon was simulated for 96 hours beginning 17 August 2008, the final 60 of which were under varying CCN concentrations as it neared the Philippines and coastal China. The model was initialized with both global reanalysis model data and irregularly spaced dropsonde data from a 2008 observational campaign using an objective analysis routine. At 36 hours, the internal nudging of the model was switched off and allowed to evolve on its own. As the typhoon entered the field of elevated CCN in the sensitivity tests, the presence of additional CCN resulted in a significant perturbation of windspeed, convective fluxes, and hydrometeor species behavior. Initially ingested in the outer rainbands of the storm, the additional CCN resulted in an initial damping and subsequent invigoration of convection. The increase in convective fluxes strongly lag-correlates with increased amounts of supercooled liquid water within the storm domain. As the convection intensified in the outer rainbands the storm drifted over the developing cold-pools, affecting the inflow of air into the convective towers of the typhoon. Changes in the timing and amount of rain produced in each simulation resulted in differing cold-pool strengths and size. The presence of additional CCN increased resulted in an amplification of convection within the storm, except for the extremely high CCN concentration simulation, which showed a damped convection due to the advection of pristine ice away from the storm. This study examines the physical mechanisms that could potentially alter a tropical cyclone (TC) in intensity and dynamics upon ingesting elevated levels of CCN. Advisors/Committee Members: Cotton, William R. (advisor), van den Heever, Susan C. (committee member), Eykholt, Richard Eric, 1956- (committee member).

Subjects/Keywords: aerosol; tropical cyclone; atmospheric modeling; Atmospheric aerosols; Atmospheric models; Cyclones – Tropics

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Krall, G. M. (2010). Potential indirect effects of aerosol on tropical cyclone development. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/44964

Chicago Manual of Style (16^th Edition):

Krall, Geoffrey Michael. “Potential indirect effects of aerosol on tropical cyclone development.” 2010. Masters Thesis, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/44964.

MLA Handbook (7^th Edition):

Krall, Geoffrey Michael. “Potential indirect effects of aerosol on tropical cyclone development.” 2010. Web. 07 Mar 2021.

Vancouver:

Krall GM. Potential indirect effects of aerosol on tropical cyclone development. [Internet] [Masters thesis]. Colorado State University; 2010. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/44964.

Council of Science Editors:

Krall GM. Potential indirect effects of aerosol on tropical cyclone development. [Masters Thesis]. Colorado State University; 2010. Available from: http://hdl.handle.net/10217/44964

Colorado State University

12. Knupp, Kevin Robert. Precipitating convective cloud downdraft structure: a synthesis of observations and modeling.

Degree: PhD, Atmospheric Science, 1985, Colorado State University

URL: http://hdl.handle.net/10217/178748

► This study represents a comprehensive investigation in which observations are integrated with three-dimensional cloud model results to examine the kinematic, dynamic and thermodynamic structure of… (more)

▼ This study represents a comprehensive investigation in which observations are integrated with three-dimensional cloud model results to examine the kinematic, dynamic and thermodynamic structure of downdrafts associated with precipitating convection. One particular downdraft type, the low-level precipitation-associated downdraft, is investigated in considerable detail. It is shown that this downdraft exhibits significant structural, dynamic and thermodynamic properties which differ appreciably from other independent downdrafts within precipitating convective clouds. General airflow and trajectory patterns within low-level downdrafts are typically convergent from ~0.8 km upwards to downdraft top, typically less than 5 km AGL. Observed mass flux profiles often increase rapidly with decreasing height as a result of strong buoyancy forcing below the melting level. Such patterns indicate that strong cooling by melting and evaporation within statically unstable low levels generates low perturbation pressure by virtue of buoyantly-induced pressure perturbations. Cloud model results verify this process and indicate that pressure perturbations are strongest during downdraft developing stages. Maximum modeled pressure reductions up to 2 mb are located within downdrafts and precipitation about 0.6 km below the 273 K level approximately 10 min after heavy precipitation (˃ 2 g kg¯¹) enters low levels. The magnitude of this buoyantly-produced pressure reduction is influenced by temperature, static stability, relative humidity and precipitation characteristics. Model results and related calculations indicate that cooling provides the impetus for downdraft formation. Melting, in particular is generally found to make significant contribution to total cooling in cases having relatively shallow (˂ 2 km) PBL. Cooling by evaporation becomes increasingly important as PBL depth increases. Inflow to the low-level downdraft, although vertically continuous, can be separated into two branches. The up-down branch originating within the PBL initially rises up to 4 km and then descends within the main precipitation downdraft. The midlevel branch, most pronounced during early downdraft stages, originates from above the PBL and transports low-valued ϴₑ to low levels. Pressure forces important along both branches act to lift stable air along the up-down branch, and provide downward forcing of positively-buoyant air in the upper regions of both branches. Two primary conclusions are drawn from the results of this study: (1) Downdrafts are driven at low levels within regions of strong static instability by strong cooling provided by melting and evaporation. Cloud level entrainment effects make secondary contributions. (2) Precipitation size and phase (e.g. melting) are probably the most important controlling parameters for downdraft strength. Advisors/Committee Members: Cotton, William R. (advisor), Brown, John M. (committee member), Stevens, Duane E. (committee member), Sinclair, Peter C. (committee member), Bienkiewicz, Bogusz (committee member).

Subjects/Keywords: Convective clouds

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Knupp, K. R. (1985). Precipitating convective cloud downdraft structure: a synthesis of observations and modeling. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/178748

Chicago Manual of Style (16^th Edition):

Knupp, Kevin Robert. “Precipitating convective cloud downdraft structure: a synthesis of observations and modeling.” 1985. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/178748.

MLA Handbook (7^th Edition):

Knupp, Kevin Robert. “Precipitating convective cloud downdraft structure: a synthesis of observations and modeling.” 1985. Web. 07 Mar 2021.

Vancouver:

Knupp KR. Precipitating convective cloud downdraft structure: a synthesis of observations and modeling. [Internet] [Doctoral dissertation]. Colorado State University; 1985. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/178748.

Council of Science Editors:

Knupp KR. Precipitating convective cloud downdraft structure: a synthesis of observations and modeling. [Doctoral Dissertation]. Colorado State University; 1985. Available from: http://hdl.handle.net/10217/178748

Colorado State University

13. Vigh, Jonathan L. Formation of the hurricane eye.

Degree: PhD, Atmospheric Science, 2010, Colorado State University

URL: http://hdl.handle.net/10217/39054

► This dissertation consists of three distinct studies which investigate aspects of eye formation. The first study reviews eye phenomenon in a variety of vortices ranging… (more)

▼ This dissertation consists of three distinct studies which investigate aspects of eye formation. The first study reviews eye phenomenon in a variety of vortices ranging from simple vortices to the menagerie of geophysical vortices, emphasizing similarities and differences to the eyes formed in hurricanes. The hurricane eye is found to be a paradoxical structure imposed by conservation of angular momentum and the boundaries of the vortex. A comprehensive definition for hurricane eye formation is proposed and various eye formation mechanisms are summarized. The next study presents a simple theoretical argument to isolate the conditions under which a tropical cyclone can rapidly develop a warm-core thermal structure and subsequently approach a steady state. The theoretical argument is based on the balanced vortex model and, in particular, on the associated transverse circulation equation and the geopotential tendency equation. The transverse circulation and the temperature tendency in a tropical vortex depend not only on the diabatic forcing, but also on the spatial distributions of the static stability, the baroclinity, and the inertial stability. The vortex response to diabatic heating depends critically on whether the heating occurs in the low inertial stability region outside the radius of maximum wind or in the high inertial stability region inside the radius of maximum wind. This result suggests that rapid intensification is favored for storms which have at least some of the eyewall convection inside the radius of maximum wind. The development of an eye partially removes diabatic heating from the high inertial stability region of the storm center, yet rapid intensification may continue if the eyewall heating continues to become more efficient. As the warm core matures and static stability increases over the inner core, conditions there become less favorable for deep upright convection and the storm tends to approach a steady state. The final study characterizes the kinematic and thermodynamic changes that occur before, during, and after the initial eye formations of a broad set of Atlantic tropical cyclones. To obtain the requisite structure and intensity parameters, a new data set has been synthesized from the Vortex Data Messages transmitted by routine aircraft reconnaissance from 1989-2008. Intensity ranges are determined for the times when the eye/eyewall structure first appears in aircraft radar and infrared satellite imagery. The mean intensity at which an eye is first observed in both aircraft or satellite imagery is found to be 58 kt, somewhat lower than reported in previous studies. Changes about the time of eye formation are examined for intensity, the radius of maximum winds, the minimum Rossby radius of deformation, eye temperature and dew point temperature depression. Storms are found to intensify most rapidly near the time of eye formation, especially when a persistent eye is observed in infrared satellite imagery. Many storms which are forming eyes are found to undergo a substantial and rapid… Advisors/Committee Members: Schubert, Wayne H. (advisor), Cotton, William R., 1940- (committee member), Ito, Takamitsu (committee member), DeMaria, Mark (committee member), Krueger, David A. (committee member).

Subjects/Keywords: warm core development; eye formation; tropical cyclone; intensification; eyewall; vortex data messages; Hurricanes; Vortex-motion; Cyclones – Tropics; Convection (Meteorology)

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Vigh, J. L. (2010). Formation of the hurricane eye. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/39054

Chicago Manual of Style (16^th Edition):

Vigh, Jonathan L. “Formation of the hurricane eye.” 2010. Doctoral Dissertation, Colorado State University. Accessed March 07, 2021. http://hdl.handle.net/10217/39054.

MLA Handbook (7^th Edition):

Vigh, Jonathan L. “Formation of the hurricane eye.” 2010. Web. 07 Mar 2021.

Vancouver:

Vigh JL. Formation of the hurricane eye. [Internet] [Doctoral dissertation]. Colorado State University; 2010. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10217/39054.

Council of Science Editors:

Vigh JL. Formation of the hurricane eye. [Doctoral Dissertation]. Colorado State University; 2010. Available from: http://hdl.handle.net/10217/39054

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations