subject:(atmosphere)

University of Hong Kong

1. 郝锡荦; Hao, Xiluo. Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets.

Degree: PhD, 2015, University of Hong Kong

URL: Hao, X. [郝锡荦]. (2015). Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5570776 ; http://dx.doi.org/10.5353/th_b5570776 ; http://hdl.handle.net/10722/228394

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The first eon of the Earth, Hadean, is no doubt critical for the evolution of Earth towards a habitable planet and the origin of life.… (more)

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The first eon of the Earth, Hadean, is no doubt critical for the evolution of Earth towards a habitable planet and the origin of life. However, there is almost no petrologic record preserved for this piece of history because of the long-term geological reworking. In this study, batch experiments simulating the interaction between the early Earth's ultramafic crust and H2O-CO2 atmosphere were performed in order to gain some new insights into the direct interaction and its influence on the evolution of mineral, atmosphere, ocean and the prebiotic chemistry on the early Earth. Electron microscopic observations (including SEM and TEM) show that the secondary minerals produced in the experiments mainly include phyllosilicates, carbonates and Fe-oxide. Phyllosilicates which are essential for biomonomer synthesis can be found in each of our experiments. Different rock-water-H2O systems result in different clay minerals with varied crystal habits. Carbonates can be found in experiments carried out at temperature below 400 ºC. With the experimental temperature decrease from 400 ºC to 200 ºC, the formed carbonates change from calcite, dolomite and magnesite accordingly. Energy dispersive spectroscopy reveals the incorporation of iron in all kinds of carbonates. Hexagonal magnetite nanoplates are observed in komatiite-H2O-CO2 experiment carried out at 450 ºC. The mineralogical compositions imply that the interaction between the early Earth's ultramafic crust and H2O-CO2 atmosphere were able to produce clay minerals, carbonates and oxides on the rocky planets such as Earth, which was corroborated by the recent discovery of layered clay minerals and carbonates assemblages on Mars. More importantly, these secondary minerals are effective in catalyzing the inorganic molecular to biomolecules that are essential in prebiotic chemical evolution. The GC measurement of the gaseous phases trapped in the capsule after experiments show that abiogenetic methane, ethane and propane as well as hydrogen were detected in most our experiments. The relative concentrations of these gases are higher in high temperature experiments, which indicate high productivity of CH4 and H2 during the interaction between the early Earth's ultramafic crust and H2O-CO2 atmosphere. The abiotic formation and accumulation of H2, methane, and short hydrocarbon would not only provide material basis for the chemical evolution towards life but also play essential roles in preventing the surface of the Earth from freezing in the Hadean eon while the Earth was suffering from extensive precipitation of atmospheric CO2 and the faint young sun. Generally, the earliest interaction between the Earth's ultramafic crust and H2O-CO2 atmosphere could have changed the physicochemical condition of the Earth's surface that favored the prebiotic chemical evolution towards life.

published_or_final_version

Earth Sciences

Doctoral

Doctor of Philosophy

Subjects/Keywords: Atmosphere

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APA (6^th Edition):

郝锡荦; Hao, X. (2015). Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. (Doctoral Dissertation). University of Hong Kong. Retrieved from Hao, X. [郝锡荦]. (2015). Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5570776 ; http://dx.doi.org/10.5353/th_b5570776 ; http://hdl.handle.net/10722/228394

Chicago Manual of Style (16^th Edition):

郝锡荦; Hao, Xiluo. “Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets.” 2015. Doctoral Dissertation, University of Hong Kong. Accessed December 10, 2019. Hao, X. [郝锡荦]. (2015). Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5570776 ; http://dx.doi.org/10.5353/th_b5570776 ; http://hdl.handle.net/10722/228394.

MLA Handbook (7^th Edition):

郝锡荦; Hao, Xiluo. “Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets.” 2015. Web. 10 Dec 2019.

Vancouver:

郝锡荦; Hao X. Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. [Internet] [Doctoral dissertation]. University of Hong Kong; 2015. [cited 2019 Dec 10]. Available from: Hao, X. [郝锡荦]. (2015). Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5570776 ; http://dx.doi.org/10.5353/th_b5570776 ; http://hdl.handle.net/10722/228394.

Council of Science Editors:

郝锡荦; Hao X. Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. [Doctoral Dissertation]. University of Hong Kong; 2015. Available from: Hao, X. [郝锡荦]. (2015). Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5570776 ; http://dx.doi.org/10.5353/th_b5570776 ; http://hdl.handle.net/10722/228394

Columbia University

2. Anber, Usama Mostafa. Idealized cloud-system resolving modeling for tropical convection studies.

Degree: 2015, Columbia University

URL: https://doi.org/10.7916/D8H13185

► A three-dimensional limited-domain Cloud-Resolving Model (CRM) is used in idealized settings to study the interaction between tropical convection and the large scale dynamics. The model… (more)

▼ A three-dimensional limited-domain Cloud-Resolving Model (CRM) is used in idealized settings to study the interaction between tropical convection and the large scale dynamics. The model domain is doubly periodic and the large-scale circulation is parameterized using the Weak Temperature Gradient (WTG) Approximation and Damped Gravity Wave (DGW) methods. The model simulations fall into two main categories: simulations with a prescribed radiative cooling profile, and others in which radiative cooling profile interacts with clouds and water vapor. For experiments with a prescribed radiative cooling profile, radiative heating is taken constant in the vertical in the troposphere. First, the effect of turbulent surface fluxes and radiative cooling on tropical deep convection is studied. In the precipitating equilibria, an increment in surface fluxes produces a greater increase in precipitation than an equal increment in column-integrated radiative heating. The gross moist stability remains close to constant over a wide range of forcings. With dry initial conditions, the system exhibits hysteresis, and maintains a dry state with for a wide range of net energy inputs to the atmospheric column under WTG. However, for the same forcings the system admits a rainy state when initialized with moist conditions, and thus multiple equilibria exist under WTG. When the net forcing is increased enough that simulations, which begin dry, eventually develop precipitation. DGW, on the other hand, does not have the tendency to develop multiple equilibria under the same conditions. The effect of vertical wind shear on tropical deep convection is also studied. The strength and depth of the shear layer are varied as control parameters. Surface fluxes are prescribed. For weak wind shear, time-averaged rainfall decreases with shear and convection remains disorganized. For larger wind shear, rainfall increases with shear, as convection becomes organized into linear mesoscale systems. This non-monotonic dependence of rainfall on shear is observed when the imposed surface fluxes are moderate. For larger surface fluxes, convection in the unsheared basic state is already strongly organized, but increasing wind shear still leads to increasing rainfall. In addition to surface rainfall, the impacts of shear on the parameterized large-scale vertical velocity, convective mass fluxes, cloud fraction, and momentum transport are also discussed. For experiments with interactive radiative cooling profile, the effect of cloud- radiation interaction on cumulus ensemble is examined in sheared and unsheared environments with both fixed and interactive sea surface temperature (SST). For fixed SST, interactive radiation, when compared to simulations in which radiative profile has the same magnitude and vertical shape but does not interact with clouds or water vapor, is found to suppress mean precipitation by inducing strong descent in the lower troposphere, increasing the gross moist stability. For interactive SST, using a slab ocean…

Subjects/Keywords: Atmosphere

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

APA (6^th Edition):

Anber, U. M. (2015). Idealized cloud-system resolving modeling for tropical convection studies. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8H13185

Chicago Manual of Style (16^th Edition):

Anber, Usama Mostafa. “Idealized cloud-system resolving modeling for tropical convection studies.” 2015. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D8H13185.

MLA Handbook (7^th Edition):

Anber, Usama Mostafa. “Idealized cloud-system resolving modeling for tropical convection studies.” 2015. Web. 10 Dec 2019.

Vancouver:

Anber UM. Idealized cloud-system resolving modeling for tropical convection studies. [Internet] [Doctoral dissertation]. Columbia University; 2015. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D8H13185.

Council of Science Editors:

Anber UM. Idealized cloud-system resolving modeling for tropical convection studies. [Doctoral Dissertation]. Columbia University; 2015. Available from: https://doi.org/10.7916/D8H13185

Columbia University

3. Coats, Sloan John. Paleoclimate Model-Data Comparisons of Hydroclimate over North America with a Focus on Megadroughts.

Degree: 2015, Columbia University

URL: https://doi.org/10.7916/D87M0760

► For the first time in the history of the Intergovernmental Panel on Climate Change, the Paleoclimate and Coupled Model Intercomparison Projects Phases 3 and 5… (more)

▼ For the first time in the history of the Intergovernmental Panel on Climate Change, the Paleoclimate and Coupled Model Intercomparison Projects Phases 3 and 5 produced an ensemble of forced transient simulations of the last millennium. This wealth of model output, when combined with a growing collection of high spatial and temporal resolution pa- leoclimate estimates of past climate variability, represents an important and unprecedented source of information on climate variability over decades to centuries. This dissertation thus combines paleoclimate evidence with climate modeling to define a physical and statistical paradigm through which to analyze these combined sources of information and subsequently to characterize the features of the North American climate system that cannot be sufficiently understood using instrumental data alone. This includes features that have long timescales of variability or that are rare, and by consequence have few degrees of freedom over the short instrumental interval (1850 C.E. to Present), as well as interannual dynamical relationships that, while potentially well characterized by observations, are non-stationary. An integrative approach to analyzing these features or relationships serves two fundamental purposes: 1) It provides a more comprehensive characterization of past climate variability, albeit with the caveat of model bias, to clarify understanding of the dynamics that produce these features or relationships in the real world; and 2) it assesses whether coupled general circulation models (CGCMs) are able to simulate these features or relationships, which is necessary to determine that state-of-the-art CGCMs can accurately constrain the risk of future climate change. The focus herein will be on multidecadal hydroclimate change, or megadroughts, in the paleoclimate record of the American Southwest to better inform our understanding of the risk of future hydroclimate change over the region. Two fundamental understandings are derived from this work. Firstly, CGCMs are successful at simulating discrete periods of mul- tidecadal hydroclimate change that are characteristic in length, magnitude, and frequency of occurrence of megadroughts in the paleoclimate record. The simulated megadroughts are not tied in any coherent way to exogenous forcing, however, suggesting that CGCMs simulate large-magnitude internal variability on multidecadal timescales. Secondly, the dynamical characteristics of CGCMs are important in determining the atmosphere-ocean variability that drives multidecadal hydroclimate change. The dynamical characteristics of relevance include teleconnection realism and stationarity, the magnitude of ocean variability, and the relative magnitudes of different modes of atmosphere-ocean and purely atmospheric vari- ability. Additionally, a new understanding of real-world megadrought dynamics is derived herein, with the characteristics of some CGGMs providing a better representation of these dynamics.

Subjects/Keywords: Atmosphere

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

APA (6^th Edition):

Coats, S. J. (2015). Paleoclimate Model-Data Comparisons of Hydroclimate over North America with a Focus on Megadroughts. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D87M0760

Chicago Manual of Style (16^th Edition):

Coats, Sloan John. “Paleoclimate Model-Data Comparisons of Hydroclimate over North America with a Focus on Megadroughts.” 2015. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D87M0760.

MLA Handbook (7^th Edition):

Coats, Sloan John. “Paleoclimate Model-Data Comparisons of Hydroclimate over North America with a Focus on Megadroughts.” 2015. Web. 10 Dec 2019.

Vancouver:

Coats SJ. Paleoclimate Model-Data Comparisons of Hydroclimate over North America with a Focus on Megadroughts. [Internet] [Doctoral dissertation]. Columbia University; 2015. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D87M0760.

Council of Science Editors:

Coats SJ. Paleoclimate Model-Data Comparisons of Hydroclimate over North America with a Focus on Megadroughts. [Doctoral Dissertation]. Columbia University; 2015. Available from: https://doi.org/10.7916/D87M0760

Columbia University

4. Li, Jing. Improving Our Understanding of Atmospheric Aerosols and Their Climate Effects: Implications for Satellite Retrievals and GCM Simulations.

Degree: 2011, Columbia University

URL: https://doi.org/10.7916/D83B663H

► This dissertation is a collection of studies focusing on improving our understanding of atmospheric aerosols using both observational data and model simulations. EOF analysis of… (more)

▼ This dissertation is a collection of studies focusing on improving our understanding of atmospheric aerosols using both observational data and model simulations. EOF analysis of Aerosol Index (AI) product from Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) reveals global distribution of absorbing aerosols, with major sources lying in Sahara deserts, the Sahel region, South America and South Africa. Analysis of aerosol Single Scattering Albedo (SSA) data from AErosol RObotic NETwork (AERONET) further indicate trends in SSA over a number of globally distributed stations, which might be associated with changes in aerosol composition and thus their optical properties. More importantly, the changes in SSA alter the radiative forcing of aerosols. They may also potentially impact satellite retrievals of aerosol properties as generally a constant SSA is assumed in the retrieval algorithms. In order to assess satellite retrieved aerosol optical properties, collocated pixel level Aerosol Optical Depth (AOD) and Ångström Exponent (AE) data from MODerate resolution Imaging Spectroradiometer (MODIS) are compared with AERONET measurements over 10 stations representing typical aerosol regimes. The results show that while MODIS AOD well agrees with AERONET in both the magnitude and seasonal variability for all stations, comparatively large discrepancies are found in the AE, especially for over land. Further investigation reveals that the dependence of the AE on AOD for MODIS data are quite different from AERONET data, which suggest problems in the aerosol models used in MODIS retrieval. MODIS ocean data are generally reliable. Focusing on ocean data, a strong correlation between the AE and ENSO index has been found, and the roles of relevant physical mechanisms are discussed. While the exact cause of the correlation is still unclear, the results indicate aerosol properties can be influenced by major climate modes such as ENSO. The sensitivity of aerosol Direct Radiative Forcing (DRF) to perturbations of major aerosol parameters are tested using the GISS GCM. Among the three perturbed parameters, AOD, SSA and asymmetry parameter g, DRF appears to be most sensitive to SSA. Moreover, changing aerosol dry sizes result in larger fluctuation in DRF than the previous three parameters. Based on the sensitivity studies, an optimal fitting technique based on AERONET data is developed to better constrain aerosol dry size parameterization in the GCM. Model results for AOD and SSA are also improved by adjusting the size and applying "uncertainty parameters". The fitting results indicate an overall underestimate in GCM aerosol loading. In particular, aerosol absorption has been underestimated by approximately a factor of 2. The low bias might be attributed to insufficient aerosol mass loading, lack of internal mixing of black carbon with other species, etc. After incorporating the optimized sizes and uncertainty parameters into the GCM, estimated global mean DRF is significantly larger than the original aerosol…

Subjects/Keywords: Atmosphere

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

APA (6^th Edition):

Li, J. (2011). Improving Our Understanding of Atmospheric Aerosols and Their Climate Effects: Implications for Satellite Retrievals and GCM Simulations. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D83B663H

Chicago Manual of Style (16^th Edition):

Li, Jing. “Improving Our Understanding of Atmospheric Aerosols and Their Climate Effects: Implications for Satellite Retrievals and GCM Simulations.” 2011. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D83B663H.

MLA Handbook (7^th Edition):

Li, Jing. “Improving Our Understanding of Atmospheric Aerosols and Their Climate Effects: Implications for Satellite Retrievals and GCM Simulations.” 2011. Web. 10 Dec 2019.

Vancouver:

Li J. Improving Our Understanding of Atmospheric Aerosols and Their Climate Effects: Implications for Satellite Retrievals and GCM Simulations. [Internet] [Doctoral dissertation]. Columbia University; 2011. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D83B663H.

Council of Science Editors:

Li J. Improving Our Understanding of Atmospheric Aerosols and Their Climate Effects: Implications for Satellite Retrievals and GCM Simulations. [Doctoral Dissertation]. Columbia University; 2011. Available from: https://doi.org/10.7916/D83B663H

5. Fraza, Erik. The Global 3-Dimensional Structure of the Pacific Decadal Oscillation.

Degree: MS, Atmospheric Sciences, 2010, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1281395658

► The Pacific Decadal Oscillation (PDO) is a dominant mode of decadal variability in the global climate system. Decadal variability is important in terms of… (more)

Subjects/Keywords: Atmosphere

…oscillations of the atmosphere-ocean system. It is finally stated that the PDO is likely a… …a recurring pattern of ocean-atmosphere variability in which the central gyre cools at the… …and 975mb vertically. A little north of this and a little higher in the atmosphere is a… …820950mb vertically. More towards the top of the atmosphere, a portion of the negative anomaly of… …atmosphere is a very strong positive air temperature anomaly. This anomaly, found in the northern…

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APA (6^th Edition):

Fraza, E. (2010). The Global 3-Dimensional Structure of the Pacific Decadal Oscillation. (Masters Thesis). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1281395658

Chicago Manual of Style (16^th Edition):

Fraza, Erik. “The Global 3-Dimensional Structure of the Pacific Decadal Oscillation.” 2010. Masters Thesis, The Ohio State University. Accessed December 10, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281395658.

MLA Handbook (7^th Edition):

Fraza, Erik. “The Global 3-Dimensional Structure of the Pacific Decadal Oscillation.” 2010. Web. 10 Dec 2019.

Vancouver:

Fraza E. The Global 3-Dimensional Structure of the Pacific Decadal Oscillation. [Internet] [Masters thesis]. The Ohio State University; 2010. [cited 2019 Dec 10]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1281395658.

Council of Science Editors:

Fraza E. The Global 3-Dimensional Structure of the Pacific Decadal Oscillation. [Masters Thesis]. The Ohio State University; 2010. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1281395658

6. Nishanth T. Variability of surface ozone and its impact on air quality over Kannur.

Degree: Physics, 2013, Kannur University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/17848

►

Ozone (O3,) produced in the troposphere plays a vital role in the radiative and chemical processes of the atmosphere due to its strong oxidizing capability.Subsequently,… (more)

▼

Ozone (O3,) produced in the troposphere plays a vital role in the radiative and chemical processes of the atmosphere due to its strong oxidizing capability.Subsequently, surface O3 is one of the ideal trace gases present in the troposphere which can modulate the chemistry to a larger extent. Being a prominent green house gas and a good tracer with fairly small lifetime, the variation in the abundance of ground level O3is an ideal method to explore the photochemistry and dynamics of the atmosphere. The chemistry that leads to tropospheric O3 formation is generally initiated by the photolysis of NO2. In the presence of solar radiation NO2 photolysis to produce NO and atomic oxygen and this atomic oxygen reacts with O2 to produce O3. The conversion of NO to NO2 without O3 occurs through a combination of the reaction cycles of hydroxyl (OH) or peroxyl radicals (HO2). In these cycles, OH radicals are converted to HO2 or RO2, through their reaction with CO or hydrocarbons. The increasing trends in ground levelO3 in the urban and rural areas of industrialized regions are strongly linked to the changes in anthropogenic emissions of O3 precursors and revealed that its key role in imparting global warming and subsequent climate changes. Over the last few decades, several studies have revealed that background O3 in the troposphere has almost doubled that compared to the pre industrial era. In order to explore surface O3 chemistry and its transport at Kannur, a tropical coastal site in the state of Kerala, continuous observations has been going on since 2009 at Kannur University with the support of ISRO-GBP (AT-CTM) programme. This thesis is focused on the observations on the variations of ground level O3 mixing ratio and its precursors at Kannur (11.9oN and 75.4oE, 5m asl), in north Kerala confined in the coastal belt of Arabian Sea and Western Ghats. In order to discuss the objectivity effectively, the thesis is divided into seven chapters.

Summary p. 156-160, References p. 161-176

Advisors/Committee Members: Satheesh Kumar M K.

Subjects/Keywords: Ozone; Atmosphere

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APA (6^th Edition):

T, N. (2013). Variability of surface ozone and its impact on air quality over Kannur. (Thesis). Kannur University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/17848

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):

T, Nishanth. “Variability of surface ozone and its impact on air quality over Kannur.” 2013. Thesis, Kannur University. Accessed December 10, 2019. http://shodhganga.inflibnet.ac.in/handle/10603/17848.

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

MLA Handbook (7^th Edition):

T, Nishanth. “Variability of surface ozone and its impact on air quality over Kannur.” 2013. Web. 10 Dec 2019.

Vancouver:

T N. Variability of surface ozone and its impact on air quality over Kannur. [Internet] [Thesis]. Kannur University; 2013. [cited 2019 Dec 10]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/17848.

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

Council of Science Editors:

T N. Variability of surface ozone and its impact on air quality over Kannur. [Thesis]. Kannur University; 2013. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/17848

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

University of Hong Kong

7. Hao, Xiluo. Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets.

Degree: PhD, 2015, University of Hong Kong

URL: http://hdl.handle.net/10722/219967

abstract

Earth Sciences

Doctoral

Doctor of Philosophy

Subjects/Keywords: Atmosphere

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

APA (6^th Edition):

Hao, X. (2015). Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. (Doctoral Dissertation). University of Hong Kong. Retrieved from http://hdl.handle.net/10722/219967

Chicago Manual of Style (16^th Edition):

Hao, Xiluo. “Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets.” 2015. Doctoral Dissertation, University of Hong Kong. Accessed December 10, 2019. http://hdl.handle.net/10722/219967.

MLA Handbook (7^th Edition):

Hao, Xiluo. “Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets.” 2015. Web. 10 Dec 2019.

Vancouver:

Hao X. Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. [Internet] [Doctoral dissertation]. University of Hong Kong; 2015. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10722/219967.

Council of Science Editors:

Hao X. Experimental approach to the direct interaction between the proto-atmosphere and rocky crust of the early earth and its implications to the early evolution of earth-like planets. [Doctoral Dissertation]. University of Hong Kong; 2015. Available from: http://hdl.handle.net/10722/219967

8. Rutten, M.A.J. The Palace: A new station entrance for Amsterdam Zuid:.

Degree: 2014, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:8a5e6dda-69d4-4e12-8e19-b7ca094d20ec

► The proposal tries to initiate a connection between Zuidas and the centre of Amsterdam, but also tries to connect the public spaces of Zuidas. This… (more)

Subjects/Keywords: atmosphere

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APA (6^th Edition):

Rutten, M. A. J. (2014). The Palace: A new station entrance for Amsterdam Zuid:. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:8a5e6dda-69d4-4e12-8e19-b7ca094d20ec

Chicago Manual of Style (16^th Edition):

Rutten, M A J. “The Palace: A new station entrance for Amsterdam Zuid:.” 2014. Masters Thesis, Delft University of Technology. Accessed December 10, 2019. http://resolver.tudelft.nl/uuid:8a5e6dda-69d4-4e12-8e19-b7ca094d20ec.

MLA Handbook (7^th Edition):

Rutten, M A J. “The Palace: A new station entrance for Amsterdam Zuid:.” 2014. Web. 10 Dec 2019.

Vancouver:

Rutten MAJ. The Palace: A new station entrance for Amsterdam Zuid:. [Internet] [Masters thesis]. Delft University of Technology; 2014. [cited 2019 Dec 10]. Available from: http://resolver.tudelft.nl/uuid:8a5e6dda-69d4-4e12-8e19-b7ca094d20ec.

Council of Science Editors:

Rutten MAJ. The Palace: A new station entrance for Amsterdam Zuid:. [Masters Thesis]. Delft University of Technology; 2014. Available from: http://resolver.tudelft.nl/uuid:8a5e6dda-69d4-4e12-8e19-b7ca094d20ec

Columbia University

9. Martin, William George Kulesz. Advancements for three-dimensional remote sensing of the atmosphere.

Degree: 2014, Columbia University

URL: https://doi.org/10.7916/D8WM1BZC

► Climate modeling efforts depend on remote sensing observations of clouds and aerosols in the atmosphere. This dissertation presents a foundation for using three-dimensional (3D) remote… (more)

Subjects/Keywords: Mathematics; Atmosphere

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APA (6^th Edition):

Martin, W. G. K. (2014). Advancements for three-dimensional remote sensing of the atmosphere. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8WM1BZC

Chicago Manual of Style (16^th Edition):

Martin, William George Kulesz. “Advancements for three-dimensional remote sensing of the atmosphere.” 2014. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D8WM1BZC.

MLA Handbook (7^th Edition):

Martin, William George Kulesz. “Advancements for three-dimensional remote sensing of the atmosphere.” 2014. Web. 10 Dec 2019.

Vancouver:

Martin WGK. Advancements for three-dimensional remote sensing of the atmosphere. [Internet] [Doctoral dissertation]. Columbia University; 2014. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D8WM1BZC.

Council of Science Editors:

Martin WGK. Advancements for three-dimensional remote sensing of the atmosphere. [Doctoral Dissertation]. Columbia University; 2014. Available from: https://doi.org/10.7916/D8WM1BZC

Columbia University

10. Orbe, Clara. Tracer-Independent Approaches to Stratosphere-Troposphere Exchange and Tropospheric Air Mass Composition.

Degree: 2013, Columbia University

URL: https://doi.org/10.7916/D81260WZ

► Two transport processes are examined. The first addresses the interaction between the stratosphere and the troposphere. We perform the first analyses of stratosphere-troposphere exchange using… (more)

▼ Two transport processes are examined. The first addresses the interaction between the stratosphere and the troposphere. We perform the first analyses of stratosphere-troposphere exchange using one-way flux distributions; diagnostics are illustrated in both idealized and comprehensive contexts. By partitioning the one-way flux across the thermal tropopause according to stratospheric residence time τ and the regions where air enters and exits the stratosphere, the one-way flux is quantified robustly without being rendered ill-defined by the short-τ eddy-diffusive singularity. Diagnostics are first computed using an idealized circulation model that has topography only in the Northern Hemisphere (NH) and is run under perpetual NH winter conditions; suitable integrations are used to determine the stratospheric mean residence time and the mass fraction of the stratosphere in any given residence-time interval. For the idealized model we find that air exiting the stratosphere in the winter hemisphere has significantly longer mean residence times than air exiting in the summer hemisphere because the winter hemisphere has a deeper circulation and stronger eddy diffusion. The complicated response of mean residence times to increased topography underlines the fact that flux distributions capture the integrated advective-diffusive tropopause-to-tropopause transport, and not merely advection by the residual-mean circulation. Extending one-way flux distributions to non-stationary flow we quantify the seasonal ventilation of the stratosphere using the state-of-the-art GEOSCCM general circulation model subject to fixed present-day climate forcings. From the one-way flux distributions, we determine the mass of the stratosphere that is in transit from the tropical tropopause back to the troposphere, partitioned according to stratospheric residence time and exit location. We find that poleward of 45N, the cross-tropopause flux of air that has resided in the stratosphere three months or less is 34 ± 10 % larger for air that enters the stratosphere in July compared to air that enters in January. During late summer and early fall the stratosphere contains about six times more air of tropical origin that is destined to exit poleward of 45S/N in both hemispheres, after an entry-to-exit residence time of six months or less, than is the case during other times of year. We find that 51 ± 1 % and 39 ± 2 % of the stratospheric air mass of tropical origin, annually averaged and integrated over all residence times, exits poleward of 10N/S in the NH and SH, respectively, with most of the mass exiting downstream of the Pacific and Atlantic storm tracks. The mean residence time of this air is found to be ~ 5.1 years in the NH and ~ 5.7 years in the SH. The second transport process addresses new diagnostics of tropospheric transport. We introduce rigorously defined air masses as a diagnostic of tropospheric transport in the context of an idealized model. The fractional contribution from each air mass partitions air at any given point according to…

Subjects/Keywords: Mathematics; Atmosphere

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APA (6^th Edition):

Orbe, C. (2013). Tracer-Independent Approaches to Stratosphere-Troposphere Exchange and Tropospheric Air Mass Composition. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D81260WZ

Chicago Manual of Style (16^th Edition):

Orbe, Clara. “Tracer-Independent Approaches to Stratosphere-Troposphere Exchange and Tropospheric Air Mass Composition.” 2013. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D81260WZ.

MLA Handbook (7^th Edition):

Orbe, Clara. “Tracer-Independent Approaches to Stratosphere-Troposphere Exchange and Tropospheric Air Mass Composition.” 2013. Web. 10 Dec 2019.

Vancouver:

Orbe C. Tracer-Independent Approaches to Stratosphere-Troposphere Exchange and Tropospheric Air Mass Composition. [Internet] [Doctoral dissertation]. Columbia University; 2013. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D81260WZ.

Council of Science Editors:

Orbe C. Tracer-Independent Approaches to Stratosphere-Troposphere Exchange and Tropospheric Air Mass Composition. [Doctoral Dissertation]. Columbia University; 2013. Available from: https://doi.org/10.7916/D81260WZ

Kansas State University

11. Becker, Dietrich D. A determination of the atmospheric potential gradient at Manhattan, Kansas.

Degree: 1933, Kansas State University

URL: http://hdl.handle.net/2097/16101

Subjects/Keywords: Atmosphere

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APA (6^th Edition):

Becker, D. D. (1933). A determination of the atmospheric potential gradient at Manhattan, Kansas. (Thesis). Kansas State University. Retrieved from http://hdl.handle.net/2097/16101

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):

Becker, Dietrich D. “A determination of the atmospheric potential gradient at Manhattan, Kansas.” 1933. Thesis, Kansas State University. Accessed December 10, 2019. http://hdl.handle.net/2097/16101.

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

MLA Handbook (7^th Edition):

Becker, Dietrich D. “A determination of the atmospheric potential gradient at Manhattan, Kansas.” 1933. Web. 10 Dec 2019.

Vancouver:

Becker DD. A determination of the atmospheric potential gradient at Manhattan, Kansas. [Internet] [Thesis]. Kansas State University; 1933. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/2097/16101.

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

Council of Science Editors:

Becker DD. A determination of the atmospheric potential gradient at Manhattan, Kansas. [Thesis]. Kansas State University; 1933. Available from: http://hdl.handle.net/2097/16101

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

University of Arizona

12. Frenzel, Carroll William, 1930-. A NUMERICAL EXPERIMENT ON THE GENERAL CIRCULATION OF THE EARTH'S ATMOSPHERE .

Degree: 1964, University of Arizona

URL: http://hdl.handle.net/10150/284527

Subjects/Keywords: Atmosphere.

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APA (6^th Edition):

Frenzel, Carroll William, 1. (1964). A NUMERICAL EXPERIMENT ON THE GENERAL CIRCULATION OF THE EARTH'S ATMOSPHERE . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/284527

Chicago Manual of Style (16^th Edition):

Frenzel, Carroll William, 1930-. “A NUMERICAL EXPERIMENT ON THE GENERAL CIRCULATION OF THE EARTH'S ATMOSPHERE .” 1964. Doctoral Dissertation, University of Arizona. Accessed December 10, 2019. http://hdl.handle.net/10150/284527.

MLA Handbook (7^th Edition):

Frenzel, Carroll William, 1930-. “A NUMERICAL EXPERIMENT ON THE GENERAL CIRCULATION OF THE EARTH'S ATMOSPHERE .” 1964. Web. 10 Dec 2019.

Vancouver:

Frenzel, Carroll William 1. A NUMERICAL EXPERIMENT ON THE GENERAL CIRCULATION OF THE EARTH'S ATMOSPHERE . [Internet] [Doctoral dissertation]. University of Arizona; 1964. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10150/284527.

Council of Science Editors:

Frenzel, Carroll William 1. A NUMERICAL EXPERIMENT ON THE GENERAL CIRCULATION OF THE EARTH'S ATMOSPHERE . [Doctoral Dissertation]. University of Arizona; 1964. Available from: http://hdl.handle.net/10150/284527

13. Arzoumanian, Emmanuel. Développement du projet SETUP (Simulations Expérimentale et Théorique Utiles à la planétologie) : application à l'étude de la physico-chimie de l'atmosphère de Titan : Developpement of the SETUP project (experimental and theoretical simulations useful for planetology) : studies applied to the physical chemistry of Titan's atmosphere.

Degree: Docteur es, Astronomie, astrophysique, 2010, Université Paris-Est

URL: http://www.theses.fr/2010PEST1046

► Le travail de cette thèse s’inscrit dans le cadre du développement du programme S.E.T.U.P. (Simulations Expérimentale et Théorique Utiles à la planétologie) dont l’objectif est… (more)

▼ Le travail de cette thèse s’inscrit dans le cadre du développement du programme S.E.T.U.P. (Simulations Expérimentale et Théorique Utiles à la planétologie) dont l’objectif est d’effectuer des simulations représentatives de l’atmosphère de Titan et de déterminer les processus physico-chimiques qui y sont impliqués. Pour ce faire, un dispositif expérimental combine deux types de dépôts d’énergie (électrons et photons) représentatifs des processus de dissociation des molécules N2 et CH4 qui composent majoritairement l’atmosphère de Titan. De plus, une technique d’analyse par spectroscopie laser doit permettre d’identifier et de quantifier des produits et donc de suivre l’évolution du mélange réactionnel in situ en temps réel.La méthodologie adoptée pour la mise en œuvre des expériences de simulations a été de caractériser l’ensemble des étapes depuis les sources énergétiques jusqu’à l’analyse des produits et de développer les outils de modélisation nécessaires à l’interprétation des expériences.Dans un premier temps, il s’est agit de mieux caractériser les deux types de photolyse du méthane envisagés. En effet, il est prévu d’utiliser soit une lampe UV délivrant un rayonnement à Lyman-α (121,6 nm) soit un laser excimère KrF pulsé délivrant un rayonnement à 248 nm. Ce dernier doit en effet permettre des études cinétiques concernant les espèces à courte durée de vie. Des expériences d’irradiation de CH4 et d’un mélange N2/CH4 aux deux longueurs d’onde ont été menées puis simulées grâce à un modèle 0D.L’analyse fine des résultats issus des irradiations de CH4 à Lyman-α montre que des travaux complémentaires sont nécessaires pour comprendre les différences entre les expériences et le modèle chimique. En particulier, une caractérisation de l’émission de la lampe s’est avérée indispensable et a été réalisée afin d’améliorer la compréhension de la chimie mise en jeu. Les résultats obtenus lors de l’irradiation à 248 nm suggèrent que la source laser utilisée pourrait provoquer l’ionisation de CH4 et induire une chimie ionique qui n’était pas envisagée au départ. Ce type d’irradiation pourrait se révéler intéressant pour étudier les processus ionosphériques de l’atmosphère de Titan. En revanche, cette source doit être abandonnée pour l’étude de la chimie des neutres. Une source pulsée à Lyman-α devra être développée.Dans un deuxième temps, trois types d’expériences préliminaires de simulations de l’atmosphère de Titan ont été effectuées. Afin de mieux comprendre l’importance relative de chaque source énergétique, des expériences dites de « plasma » où N2 et CH4 sont dissociés simultanément dans un plasma crée par décharge microonde, ont tout d’abord été menées. Ensuite, des expériences dites de « post-décharge » où CH4 est introduit dans l’enceinte après la dissociation de N2 par plasma, ont été conduites. Et enfin, des expériences dites de « couplage », censées mieux représenter les processus de l’atmosphère de Titan où CH4, toujours introduit en post-décharge, est cette fois photodissocié à Lyman-α, ont été réalisées.Lors des… Advisors/Committee Members: Gazeau, Marie-Claire (thesis director).

Subjects/Keywords: Titan; Atmosphere; Simulations; Titan; Atmosphere; Simulations

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APA (6^th Edition):

Arzoumanian, E. (2010). Développement du projet SETUP (Simulations Expérimentale et Théorique Utiles à la planétologie) : application à l'étude de la physico-chimie de l'atmosphère de Titan : Developpement of the SETUP project (experimental and theoretical simulations useful for planetology) : studies applied to the physical chemistry of Titan's atmosphere. (Doctoral Dissertation). Université Paris-Est. Retrieved from http://www.theses.fr/2010PEST1046

Chicago Manual of Style (16^th Edition):

Arzoumanian, Emmanuel. “Développement du projet SETUP (Simulations Expérimentale et Théorique Utiles à la planétologie) : application à l'étude de la physico-chimie de l'atmosphère de Titan : Developpement of the SETUP project (experimental and theoretical simulations useful for planetology) : studies applied to the physical chemistry of Titan's atmosphere.” 2010. Doctoral Dissertation, Université Paris-Est. Accessed December 10, 2019. http://www.theses.fr/2010PEST1046.

MLA Handbook (7^th Edition):

Arzoumanian, Emmanuel. “Développement du projet SETUP (Simulations Expérimentale et Théorique Utiles à la planétologie) : application à l'étude de la physico-chimie de l'atmosphère de Titan : Developpement of the SETUP project (experimental and theoretical simulations useful for planetology) : studies applied to the physical chemistry of Titan's atmosphere.” 2010. Web. 10 Dec 2019.

Vancouver:

Arzoumanian E. Développement du projet SETUP (Simulations Expérimentale et Théorique Utiles à la planétologie) : application à l'étude de la physico-chimie de l'atmosphère de Titan : Developpement of the SETUP project (experimental and theoretical simulations useful for planetology) : studies applied to the physical chemistry of Titan's atmosphere. [Internet] [Doctoral dissertation]. Université Paris-Est; 2010. [cited 2019 Dec 10]. Available from: http://www.theses.fr/2010PEST1046.

Council of Science Editors:

Arzoumanian E. Développement du projet SETUP (Simulations Expérimentale et Théorique Utiles à la planétologie) : application à l'étude de la physico-chimie de l'atmosphère de Titan : Developpement of the SETUP project (experimental and theoretical simulations useful for planetology) : studies applied to the physical chemistry of Titan's atmosphere. [Doctoral Dissertation]. Université Paris-Est; 2010. Available from: http://www.theses.fr/2010PEST1046

Columbia University

14. Brumer, Sophia Eleonora. Wave breaking at high wind speeds and its effects on air-sea gas transfer.

Degree: 2017, Columbia University

URL: https://doi.org/10.7916/D8RF66FX

► Gravity waves are ubiquitous at the surface of the ocean and play a key role in the coupled ocean-atmosphere system. These wind generated waves, for… (more)

▼ Gravity waves are ubiquitous at the surface of the ocean and play a key role in the coupled ocean-atmosphere system. These wind generated waves, for which gravity provides the restoring force, influence the kinematics and dynamics of the upper ocean and lower atmosphere. Their breaking injects turbulence into the upper ocean, generates bubble plumes and sea-spray thus transferring energy, momentum, heat and mass between the atmosphere and the ocean. In the anthropocene, with CO2 driving the warming trend and the ocean acting as the main carbon sink, it is imperative to understand the complex physical controls of air-sea gas transfer. Large uncertainties still remain under high wind speed conditions where wave breaking processes are dominant. This dissertation seeks to shed light onto the dependence of wave breaking and air-sea gas transfer on environmental parameters. It further explores process based models of air-sea gas transfer that explicitly account for the breaking related processes. Air entraining breaking waves are easily detectable as bright features on the ocean surface composed of foam and subsurface bubble plumes. These features, termed whitecaps, arise at wind speed as as low as 3 m s−1 . The whitecap coverage (W) has been recognized as a useful proxy for quantifying wave breaking related processes. It can be determined from shipboard, air-borne and satellite remote sensing. W is most commonly parameterized as a function of wind speed, but previous parameterizations display over three orders of magnitude scatter. Concurrent wave field and flux measurements acquired during the Southern Ocean Gas Exchange (SO GasEx) and the High Wind Gas exchange Study (HiWinGS) projects permitted evaluation of the dependence of W on wind speed, wave age, wave steepness, mean square slope, as well as on wave-wind and breaking Reynolds numbers. W was determined from over 600 high frequency visible imagery recordings of 20 minutes each. Wave statistics were computed from in situ and remotely sensed data as well as from a WAVEWATCH-III® hind cast. The first ship-borne estimates of W under sustained wind speeds (U10N ) of 25 m s−1 were obtained during HiWinGS. These measurements suggest that W levels off at high wind speed, not exceeding 10% when averaged over 20 minutes. Combining wind speed and wave height in the form of the wave-wind Reynolds number resulted in closely agreeing models for both datasets, individually and combined. These are also in good agreement with two previous studies. When expressing W in terms of wave field statistics only or wave age, larger scatter is observed and/or there is little agreement between SO GasEx, HiWinGS, and previously published data. The wind–speed-only parameterizations deduced from the SO GasEx and HiWinGS datasets agree closely and capture more of the observed W variability than Reynolds number parameterizations. However, these wind-speed-only models do not agree as well with previous studies than the wind-wave Reynolds numbers. The ability to quantify air-sea gas transfer…

Subjects/Keywords: Oceanography; Atmosphere; Ocean-atmosphere interaction; Gravity waves

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APA (6^th Edition):

Brumer, S. E. (2017). Wave breaking at high wind speeds and its effects on air-sea gas transfer. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8RF66FX

Chicago Manual of Style (16^th Edition):

Brumer, Sophia Eleonora. “Wave breaking at high wind speeds and its effects on air-sea gas transfer.” 2017. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D8RF66FX.

MLA Handbook (7^th Edition):

Brumer, Sophia Eleonora. “Wave breaking at high wind speeds and its effects on air-sea gas transfer.” 2017. Web. 10 Dec 2019.

Vancouver:

Brumer SE. Wave breaking at high wind speeds and its effects on air-sea gas transfer. [Internet] [Doctoral dissertation]. Columbia University; 2017. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D8RF66FX.

Council of Science Editors:

Brumer SE. Wave breaking at high wind speeds and its effects on air-sea gas transfer. [Doctoral Dissertation]. Columbia University; 2017. Available from: https://doi.org/10.7916/D8RF66FX

15. Jougla, Thibault. Sur l'émergence et l'évolution des jets et des vortex dans les atmosphères planétaires turbulentes : On the emergence and evolution of jets and vortices in turbulent planetary atmospheres.

Degree: Docteur es, Océan, Atmosphère, Hydrologie, 2018, Grenoble Alpes; University of Saint Andrews

URL: http://www.theses.fr/2018GREAU043

► Cette thèse étudie la formation et l'évolution des jets et des vortexdans les atmosphères planétaires turbulentes, à l'aide d'une doubleapproche de simulations numériques et d'expériences… (more)

▼ Cette thèse étudie la formation et l'évolution des jets et des vortexdans les atmosphères planétaires turbulentes, à l'aide d'une doubleapproche de simulations numériques et d'expériences delaboratoire. Pour l'approche numérique, un modèle en fluidesshallow-water quasi-géostrophique à deux couches dans le plan betaavec des conditions canal a été utilisé. Comme dans Panetta (1988), onimplémente un cisaillement vertical pour représenter le gradientlatitudinal de température moyenné spatialement, qui est partiellementmaintenu par un forçage thermique. Les instabilités baroclinesaffaiblissent le gradient de température, alors que le forçagethermique le restaure, ce qui crée une dynamique non-linéaire trèsriche.Tout d'abord, nous avons considéré l'écoulement sur un fond plat, etavons modélisé les mouvements convectifs par des paires decyclones/anticyclones ou `hetons' comme dans Thomson (2016). Nousobtenons ainsi des jets principalement baroclines, oscillants entredes phases calmes et des phases turbulentes, où l'écoulement perd sazonalité. Des vortex se forment à partir des jets méandreux etl'énergie zonale diminue alors que l'énergie tourbillonnaireaugmente. Ces phases turbulentes durent typiquement pendant unepériode de relaxation du forçage thermique. On étudie les effets ducisaillement vertical, du forçage thermique et des hetons, enregardant les transferts d'énergie entre les énergies cinétiques etpotentielles, leurs composantes barotropes et baroclines ainsi queleurs composantes zonales et tourbillonnaires. Ceci nous amène àrepenser le paradigme classique des transferts d'énergie présenté dansSalmon (1982). De plus, nous étudions comment une analyse de stabilitélinéaire de l'écoulement zonal instantané est reliée aux phases calmeset turbulentes.Ensuite, nous considérons l'effet d'une topographie de grande échelle,comme une première approche pour comprendre le rôle de la topographiedans la formation des jets et des vortex. Nous utilisons le mêmemodèle que dans la première étude mais nous ajoutons un fondtopographique linéaire méridionalement, qui a l'avantage de dépendred'un seul paramètre, la pente. Une pente négative approfondit lacouche inférieure par rapport à un fond plat, ce qui augmente lepotentiel des instabilités baroclines, alors qu'une pente positive aun effet stabilisateur. Nous supprimons le forçage par les hetons etperturbons l'écoulement grâce à une zone de Rossby de faibleamplitude dans la couche inférieure à l'instant initial. L'effetprincipal du forçage par les hetons est d'agir comme une sorted'amortissement : les fluctuations de l'énergie sont constamment plusextrêmes que sans forçage. Une analyse de stabilité linéaire esteffectuée afin de déterminer les zones de stabilité etd'instabilité.Pour l'étude expérimentale, nous utilisons une cuve tournanteremplie par deux couches de fluides avec une stratification au sel etun couvercle rigide en rotation différentielle. Nous étudions unfront barocliniquement instable dans le régime des vacillationsd'amplitude, qui est caractérisé par l'émergence et… Advisors/Committee Members: Flor, Jan bert (thesis director).

Subjects/Keywords: Jets; Vortex; Atmosphere; Jets; Vortices; Atmosphere; 520

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APA (6^th Edition):

Jougla, T. (2018). Sur l'émergence et l'évolution des jets et des vortex dans les atmosphères planétaires turbulentes : On the emergence and evolution of jets and vortices in turbulent planetary atmospheres. (Doctoral Dissertation). Grenoble Alpes; University of Saint Andrews. Retrieved from http://www.theses.fr/2018GREAU043

Chicago Manual of Style (16^th Edition):

Jougla, Thibault. “Sur l'émergence et l'évolution des jets et des vortex dans les atmosphères planétaires turbulentes : On the emergence and evolution of jets and vortices in turbulent planetary atmospheres.” 2018. Doctoral Dissertation, Grenoble Alpes; University of Saint Andrews. Accessed December 10, 2019. http://www.theses.fr/2018GREAU043.

MLA Handbook (7^th Edition):

Jougla, Thibault. “Sur l'émergence et l'évolution des jets et des vortex dans les atmosphères planétaires turbulentes : On the emergence and evolution of jets and vortices in turbulent planetary atmospheres.” 2018. Web. 10 Dec 2019.

Vancouver:

Jougla T. Sur l'émergence et l'évolution des jets et des vortex dans les atmosphères planétaires turbulentes : On the emergence and evolution of jets and vortices in turbulent planetary atmospheres. [Internet] [Doctoral dissertation]. Grenoble Alpes; University of Saint Andrews; 2018. [cited 2019 Dec 10]. Available from: http://www.theses.fr/2018GREAU043.

Council of Science Editors:

Jougla T. Sur l'émergence et l'évolution des jets et des vortex dans les atmosphères planétaires turbulentes : On the emergence and evolution of jets and vortices in turbulent planetary atmospheres. [Doctoral Dissertation]. Grenoble Alpes; University of Saint Andrews; 2018. Available from: http://www.theses.fr/2018GREAU043

Victoria University of Wellington

16. Hrstich, Danielle. An Atmospheric Surface.

Degree: 2015, Victoria University of Wellington

URL: http://hdl.handle.net/10063/4802

► This thesis considers how to use atmosphere as a driver when designing to strengthen the relationship between the body and architecture. Wigley, following Semper, argues… (more)

Subjects/Keywords: Atmosphere; Kinetic; Surface

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APA (6^th Edition):

Hrstich, D. (2015). An Atmospheric Surface. (Masters Thesis). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/4802

Chicago Manual of Style (16^th Edition):

Hrstich, Danielle. “An Atmospheric Surface.” 2015. Masters Thesis, Victoria University of Wellington. Accessed December 10, 2019. http://hdl.handle.net/10063/4802.

MLA Handbook (7^th Edition):

Hrstich, Danielle. “An Atmospheric Surface.” 2015. Web. 10 Dec 2019.

Vancouver:

Hrstich D. An Atmospheric Surface. [Internet] [Masters thesis]. Victoria University of Wellington; 2015. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10063/4802.

Council of Science Editors:

Hrstich D. An Atmospheric Surface. [Masters Thesis]. Victoria University of Wellington; 2015. Available from: http://hdl.handle.net/10063/4802

Victoria University of Wellington

17. Amour, Sol. Body | Sense Experience: An Architecture of Atmosphere and Light.

Degree: 2012, Victoria University of Wellington

URL: http://hdl.handle.net/10063/2602

► This thesis explores notions of the immaterial and metaphysical in architecture. It seeks to ‘elicit a sense of wonder’ in a participant of experiential space… (more)

Subjects/Keywords: Affect; Atmosphere; Light

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APA (6^th Edition):

Amour, S. (2012). Body | Sense Experience: An Architecture of Atmosphere and Light. (Masters Thesis). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/2602

Chicago Manual of Style (16^th Edition):

Amour, Sol. “Body | Sense Experience: An Architecture of Atmosphere and Light.” 2012. Masters Thesis, Victoria University of Wellington. Accessed December 10, 2019. http://hdl.handle.net/10063/2602.

MLA Handbook (7^th Edition):

Amour, Sol. “Body | Sense Experience: An Architecture of Atmosphere and Light.” 2012. Web. 10 Dec 2019.

Vancouver:

Amour S. Body | Sense Experience: An Architecture of Atmosphere and Light. [Internet] [Masters thesis]. Victoria University of Wellington; 2012. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10063/2602.

Council of Science Editors:

Amour S. Body | Sense Experience: An Architecture of Atmosphere and Light. [Masters Thesis]. Victoria University of Wellington; 2012. Available from: http://hdl.handle.net/10063/2602

Victoria University of Wellington

18. Tyrrell, Sarah. Endemic Light.

Degree: 2017, Victoria University of Wellington

URL: http://hdl.handle.net/10063/6830

► This thesis explores endemic light and atmosphere through the shifting scales of three architectural interventions. These interventions are guided by site and theoretical research, providing… (more)

Subjects/Keywords: Architecture; Light; Atmosphere

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APA (6^th Edition):

Tyrrell, S. (2017). Endemic Light. (Masters Thesis). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/6830

Chicago Manual of Style (16^th Edition):

Tyrrell, Sarah. “Endemic Light.” 2017. Masters Thesis, Victoria University of Wellington. Accessed December 10, 2019. http://hdl.handle.net/10063/6830.

MLA Handbook (7^th Edition):

Tyrrell, Sarah. “Endemic Light.” 2017. Web. 10 Dec 2019.

Vancouver:

Tyrrell S. Endemic Light. [Internet] [Masters thesis]. Victoria University of Wellington; 2017. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10063/6830.

Council of Science Editors:

Tyrrell S. Endemic Light. [Masters Thesis]. Victoria University of Wellington; 2017. Available from: http://hdl.handle.net/10063/6830

Univerzitet u Beogradu

19. Marčeta, Dušan M. Mogućnosti i optimizacija sletanja na južnu hemisferu Marsa.

Degree: Matematički fakultet, 2016, Univerzitet u Beogradu

URL: https://fedorabg.bg.ac.rs/fedora/get/o:11265/bdef:Content/get

►

Astronomija / Astronomy

Skoro 40 godina nakon prvog uspesnog sletanja na Mars, istrazivanje njegove povrsine pomocu kosmickih letelica i dalje predstavlja ogroman naucni i tehnoloski… (more)

Subjects/Keywords: Mars; atmosphere; landing

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

APA (6^th Edition):

Marčeta, D. M. (2016). Mogućnosti i optimizacija sletanja na južnu hemisferu Marsa. (Thesis). Univerzitet u Beogradu. Retrieved from https://fedorabg.bg.ac.rs/fedora/get/o:11265/bdef:Content/get

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):

Marčeta, Dušan M. “Mogućnosti i optimizacija sletanja na južnu hemisferu Marsa.” 2016. Thesis, Univerzitet u Beogradu. Accessed December 10, 2019. https://fedorabg.bg.ac.rs/fedora/get/o:11265/bdef:Content/get.

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

MLA Handbook (7^th Edition):

Marčeta, Dušan M. “Mogućnosti i optimizacija sletanja na južnu hemisferu Marsa.” 2016. Web. 10 Dec 2019.

Vancouver:

Marčeta DM. Mogućnosti i optimizacija sletanja na južnu hemisferu Marsa. [Internet] [Thesis]. Univerzitet u Beogradu; 2016. [cited 2019 Dec 10]. Available from: https://fedorabg.bg.ac.rs/fedora/get/o:11265/bdef:Content/get.

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

Council of Science Editors:

Marčeta DM. Mogućnosti i optimizacija sletanja na južnu hemisferu Marsa. [Thesis]. Univerzitet u Beogradu; 2016. Available from: https://fedorabg.bg.ac.rs/fedora/get/o:11265/bdef:Content/get

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

University of Hawaii – Manoa

20. Wang, Xueliang. The relationship between intraseasonal disturbance activity and interannual variation of the tropical atmosphere.

Degree: PhD, 2009, University of Hawaii – Manoa

URL: http://hdl.handle.net/10125/9976

►

Typescript.

Bibliography: leaves 147-154.

Microfilm.

xx, 154 leaves, bound ill. 29 cm

The relationship between intraseasonal disturbance activity (cluster of disturbances) 'and interannual variation of… (more)

▼

Typescript.

Bibliography: leaves 147-154.

Microfilm.

xx, 154 leaves, bound ill. 29 cm

The relationship between intraseasonal disturbance activity (cluster of disturbances) 'and interannual variation of tropical atmosphere is investigated using five years (1979-83) of outgoing longwave radiation (OLR) and wind data. The space and time scale of the disturbance cluster, as defined by spectral amplitude, are much larger than those of individual disturbances. The nonlinear energy cascade between intraseasonal activity and interannual modes, in terms of a frequency modulation process, increases before and after ENSO, and decreases during ENSO. Two constructed period bands of disturbance activity, i.e., 2-15 day and 30-60 day, exhibit different spatial and temporal variations on interannual time scale. The 2-15 day activity is primarily associated with interannual variations, while the 30-60 day activity is strongest over the equatorial Indian Ocean and western Pacific prior to the 1982/83 ENSO onset and below normal during the episode. There is evidence that the 30-60 day oscillation is one of the triggering mechanisms for the 1982/83 ENSO event. The results of empirical orthogonal function analysis show that ENSO, as the most dominant mode of interannual variations, is essentially one realization of a bimodal climate system. The occurrence of ENSO is the phase shift from non-ENSO steady state to ENSO steady state. The transition period is relatively short with enhanced intraseasonal disturbance, and ENSO state lasts much shorter than non-ENSO state does. The largest and most easily detectable climate signal (interannual variability) over the central and eastern Pacific is traceable to the western Pacific-Indian Ocean region (a warm pool), and is phase locked to seasonality. It is suggested that an interaction among intraseasonal activity, annual cycle, and interannual modes over the warm pool region may be instrumental in leading to ENSO onset. The phase changes for the 1982/83 ENSO event are from the pre-ENSO in Jan. 1982, through the mid-ENSO in Jan. 1983, and back to post-ENSO of Dec. 1983. Associated with this cycle is an eastward migration of interannual component of OLR and zonal winds along the equator from the Indian Ocean, across the maritime continent, to the eastern Pacific. Both the pre-ENSO and post-ENSO are possible representatives of anti-ENSO, an extreme of non-ENSO steady state. The pre-ENSO (or post-ENSO) and mid-ENSO (mature ENSO) are phase locked with the annual cycle. The pre-ENSO (or post-ENSO) synoptics are the manifestation of an anomalous enhancement of the characteristics of the normal winter circulation, whereas the mid-ENSO patterns reflect an unusual weakening of the normal winter circulation. Thus, the mid-ENSO exhibits an approximate reversal of the synoptics from the pre-ENSO (or post-ENSO) phase. Over the North and South Pacific between about the date line and 120oW, an important area for the 1982/83 ENSO, the main characteristics of the pre-ENSO (or post-ENSO) and mid-ENSO…

Subjects/Keywords: Atmosphere – Research; Tropics

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

APA (6^th Edition):

Wang, X. (2009). The relationship between intraseasonal disturbance activity and interannual variation of the tropical atmosphere. (Doctoral Dissertation). University of Hawaii – Manoa. Retrieved from http://hdl.handle.net/10125/9976

Chicago Manual of Style (16^th Edition):

Wang, Xueliang. “The relationship between intraseasonal disturbance activity and interannual variation of the tropical atmosphere.” 2009. Doctoral Dissertation, University of Hawaii – Manoa. Accessed December 10, 2019. http://hdl.handle.net/10125/9976.

MLA Handbook (7^th Edition):

Wang, Xueliang. “The relationship between intraseasonal disturbance activity and interannual variation of the tropical atmosphere.” 2009. Web. 10 Dec 2019.

Vancouver:

Wang X. The relationship between intraseasonal disturbance activity and interannual variation of the tropical atmosphere. [Internet] [Doctoral dissertation]. University of Hawaii – Manoa; 2009. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10125/9976.

Council of Science Editors:

Wang X. The relationship between intraseasonal disturbance activity and interannual variation of the tropical atmosphere. [Doctoral Dissertation]. University of Hawaii – Manoa; 2009. Available from: http://hdl.handle.net/10125/9976

University of Helsinki

21. Ignatius, Karoliina. Building a theory for heterogeneous ice nucleation.

Degree: 2013, University of Helsinki

URL: http://hdl.handle.net/10138/39596

►

The ice crystals in the Earth’s atmosphere have a considerable impact on cloud optical and radiati- ve properties, such as reflectivity, cloud dynamics, chemical processes… (more)

▼

The ice crystals in the Earth’s atmosphere have a considerable impact on cloud optical and radiati- ve properties, such as reflectivity, cloud dynamics, chemical processes and initiation of precipitation and cloud lifetime. Thus, they directly affect the albedo of Earth which in turn is a significant factor concerning the climate change. The first step of ice formation, the phase transition from liquid to solid, is called ice nucleation. Ice has been identified to form in the atmosphere both homogeneously - without the presence of a foreign substance - and heterogeneously, i.e. induced by pre-existing surfaces. Heterogeneous ice nucleation is the primary pathway of ice formation in the atmosphere. Also homogeneous ice nucleation happens at the upper troposphere, but it requires very low temperatures, whereas in heterogeneous freezing the free energy needed for crystallization is lower and freezing can happen at higher temperatures, normally above -37 ◦ C. In heterogeneous ice nucleation, there are four freezing mechanism called modes that describe the onset conditions for freezing. They are called deposition, immersion, condensation and contact modes. The seed particles on which ice forms in heterogeneous ice nucleation are called ice nuclei (IN). Typical IN particles include mineral dust, soot, metal, bacteria and other bioaerosols (pollen, fungal spores), humic-like substances, solid ammonium sulphate, organic acids and volcanic ash. This thesis is a literature survey on the current theoretical knowledge on heterogeneous ice nucleation. It has been long known that the classical nucleation theory (CNT), if employed with one constant contact angle does not reproduce the experimental results. This is due to the fundamental assumptions of CNT: the spherical form of the initial ice embryo having properties of the bulk ice crystal; uniform surfaces; equal nucleation probability for each particle; and stochastic freezing behaviour. To solve this challenge, several theoretical and empirical extensions of CNT have been derived: the use of a distribution of contact angles and active sites; integrating individual nucleation rates over measured size spectra of the IN; and using Ice Nuclei Active Surfaces Sites (INAS) density as a normalized metric from different experiments. As a result of this literature survey, three main lines of research on this field can be distinguished: (1) ice nuclei characterisation; (2) theoretical and empirical modelling of the heterogeneous ice nucleation scheme; (3) parameterising heterogeneous ice nucleation for cloud and climate models. These lines are not altogether separate, but intertwined: knowledge of e.g. the surface properties of the IN is essential for deriving theoretical formulations. Parameterisations, on the other hand, are very much needed in order to obtain knowledge about the indirect climatic effect of ice in the atmosphere.

Vain tiivistelmä. Opinnäytteiden arkistokappaleet ovat luettavissa Helsingin yliopiston kirjastossa. Hae HELKA-tietokannasta…

Subjects/Keywords: Atmosphere-Biosphere Studies

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

APA (6^th Edition):

Ignatius, K. (2013). Building a theory for heterogeneous ice nucleation. (Thesis). University of Helsinki. Retrieved from http://hdl.handle.net/10138/39596

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):

Ignatius, Karoliina. “Building a theory for heterogeneous ice nucleation.” 2013. Thesis, University of Helsinki. Accessed December 10, 2019. http://hdl.handle.net/10138/39596.

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

MLA Handbook (7^th Edition):

Ignatius, Karoliina. “Building a theory for heterogeneous ice nucleation.” 2013. Web. 10 Dec 2019.

Vancouver:

Ignatius K. Building a theory for heterogeneous ice nucleation. [Internet] [Thesis]. University of Helsinki; 2013. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10138/39596.

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

Council of Science Editors:

Ignatius K. Building a theory for heterogeneous ice nucleation. [Thesis]. University of Helsinki; 2013. Available from: http://hdl.handle.net/10138/39596

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

University of Helsinki

22. Pokharel, Pramod. Concentrations of carbonaceous aerosols at Hyytiälä, Finland.

Degree: 2014, University of Helsinki

URL: http://hdl.handle.net/10138/135746

►

An aerosol is a colloid of fine solid particles or liquid droplet, in air or another gas (Hinds, 1999).The total carbon (TC) in carbonaceous aerosols… (more)

▼

An aerosol is a colloid of fine solid particles or liquid droplet, in air or another gas (Hinds, 1999).The total carbon (TC) in carbonaceous aerosols can be divided into Inorganic Carbon (IC), Organic Carbon (OC) and Elemental Carbon (EC).We measured carbonaceous aerosols at theSMEAR II (Station for measuring ecosystem atmosphere relations) in southern Finland based on division of Atmospheric Sciences of University of Helsinki. The measurements were carried out continuously from 2005 using different instruments. We used a thermal-optical method to analyze carbonaceous aerosols at Hyytiälä and examineddiurnal and seasonal variation in EC, OC, TC, OC/EC ratio, black carbon (BC) and organics. We found the mean concentrations of EC and OC estimated using Sunset Lab. OCEC analyzer and BC measured using Magee scientific Aethalometer were 0.22±0.19 µgC/m3, 1.53±0.92µgC/m3 and 0.35±0.30 µg/m3 respectively. Whereas the average concentration of BC measured using MAAP was 0.2±0.2 µg/m3. We also found concentrations of EC and BC to be low in summer and high in winter, whereas, the opposite was true for OC. EC, OC and BC showed no significant diurnal cycle, but clear seasonal cycle in all carbonaceous aerosols was evident. The aerosols mass measured by aerosolmass spectrometer (AMS) showed 58% organics, 28% sulfates, 5% nitrates, 9% ammonium and less than 1% chlorides at Hyytiälä.The primary organic carbon (POC) and secondary organic carbon (SOC) estimated by EC-tracer method contributed 5% and 95% respectively to the OC concentrations at Hyytiälä. The relations between different measurement instruments showed a good agreement.

Vain tiivistelmä. Opinnäytteiden arkistokappaleet ovat luettavissa Helsingin yliopiston kirjastossa. Hae HELKA-tietokannasta (http://www.helsinki.fi/helka/index.htm).

Abstract only. The paper copy of the whole thesis is available for reading room use at the Helsinki University Library. Search HELKA online catalog (http://www.helsinki.fi/helka/index.htm).

Endast avhandlingens sammandrag. Pappersexemplaret av hela avhandlingen finns för läsesalsbruk i Helsingfors universitets bibliotek. Sök i HELKA-databasen (http://www.helsinki.fi/helka/index.htm).

Subjects/Keywords: Atmosphere-Biosphere Studies

Record Details Similar Records Cite « Share

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

APA (6^th Edition):

Pokharel, P. (2014). Concentrations of carbonaceous aerosols at Hyytiälä, Finland. (Thesis). University of Helsinki. Retrieved from http://hdl.handle.net/10138/135746

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):

Pokharel, Pramod. “Concentrations of carbonaceous aerosols at Hyytiälä, Finland.” 2014. Thesis, University of Helsinki. Accessed December 10, 2019. http://hdl.handle.net/10138/135746.

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

MLA Handbook (7^th Edition):

Pokharel, Pramod. “Concentrations of carbonaceous aerosols at Hyytiälä, Finland.” 2014. Web. 10 Dec 2019.

Vancouver:

Pokharel P. Concentrations of carbonaceous aerosols at Hyytiälä, Finland. [Internet] [Thesis]. University of Helsinki; 2014. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10138/135746.

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

Council of Science Editors:

Pokharel P. Concentrations of carbonaceous aerosols at Hyytiälä, Finland. [Thesis]. University of Helsinki; 2014. Available from: http://hdl.handle.net/10138/135746

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

University of Helsinki

23. Pei, Xiangyu. Studying the formation of atmospheric aerosol particles in coastal and marine environments: analysis of CalNex and Mace Head measurements.

Degree: 2013, University of Helsinki

URL: http://hdl.handle.net/10138/38146

►

Atmospheric aerosol particles play an important role in atmospheric processes, and have a significant impact on global climate, air quality and human health. The climatic… (more)

▼

Atmospheric aerosol particles play an important role in atmospheric processes, and have a significant impact on global climate, air quality and human health. The climatic effects of secondary aerosol still represent one of the largest uncertainties limiting the understanding of climate change. The secondary aerosol originates from gas-to-particle conversion, which is also called New Particle Formation (NPF). NPF in the marine and coastal air has not been clearly studied. In many coastal areas new particle formation appears frequently, however, in remote marine environments, NPF events occur only occasionally. Moreover, some ship measurements have also been conducted to study nucleation on the ocean. The aims of this thesis are to obtain more information on neutral charged particles during the coastal NPF, to elucidate the different behaviors of negative particles and positive particles near the coastal line and on the ocean, and to speculate the mechanism of NPF. To achieve these goals, AIS and DMPS/SMPS are utilized to acquire the particles number size distribution during the ship cruise of CalNex 2010 campaign and at Mace Head, Ireland. The NPF days are classified based on the time series of the number size distribution. The growth rates and formation rates of particles, and other factors such as CS, solar radiation, SO2 concentration, ozone concentration, sulfuric and acid proxy and water level are also studied during the NPF event days to get the information and characteristics of the NPF near the coastal line. The backward trajectories are investigated to get to know the origin of the air mass when the NPF happened and the cluster analysis of backward trajectories are conducted to illustrate the relation between different origins of air mass and the frequencies of NPF events. The main outcomes of this thesis show that the dynamic processes of NPF and subsequent growth of particles in the marine and costal atmosphere are probably the same around the world. In general, sulfuric acid peak concentration was not correlated with the NPF in the marine and coastal atmosphere, other condensing vapors, such as organic vapors are needed to form the new particles and make them grow to large size. Low pre-existing particle concentrations and passage over land are necessary for NPF in the marine and coastal atmosphere. To improve the understanding of atmospheric NPF in coastal and marine environment, further field measurements and laboratory experiments should be conducted to monitor the gas-phase nucleating vapors and chemical compositions of neutral and ionic clusters and nano-particles simultaneously.

Vain tiivistelmä. Opinnäytteiden arkistokappaleet ovat luettavissa Helsingin yliopiston kirjastossa. Hae HELKA-tietokannasta (http://www.helsinki.fi/helka/index.htm).

Abstract only. The paper copy of the whole thesis is available for reading room use at the Helsinki University Library. Search HELKA online catalog (http://www.helsinki.fi/helka/index.htm).

Endast avhandlingens sammandrag. Pappersexemplaret av…

Subjects/Keywords: Atmosphere-Biosphere Studies

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Pei, X. (2013). Studying the formation of atmospheric aerosol particles in coastal and marine environments: analysis of CalNex and Mace Head measurements. (Thesis). University of Helsinki. Retrieved from http://hdl.handle.net/10138/38146

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):

Pei, Xiangyu. “Studying the formation of atmospheric aerosol particles in coastal and marine environments: analysis of CalNex and Mace Head measurements.” 2013. Thesis, University of Helsinki. Accessed December 10, 2019. http://hdl.handle.net/10138/38146.

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

MLA Handbook (7^th Edition):

Pei, Xiangyu. “Studying the formation of atmospheric aerosol particles in coastal and marine environments: analysis of CalNex and Mace Head measurements.” 2013. Web. 10 Dec 2019.

Vancouver:

Pei X. Studying the formation of atmospheric aerosol particles in coastal and marine environments: analysis of CalNex and Mace Head measurements. [Internet] [Thesis]. University of Helsinki; 2013. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10138/38146.

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

Council of Science Editors:

Pei X. Studying the formation of atmospheric aerosol particles in coastal and marine environments: analysis of CalNex and Mace Head measurements. [Thesis]. University of Helsinki; 2013. Available from: http://hdl.handle.net/10138/38146

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

University of Helsinki

24. Garmash, Olga. The Formation of Extremely Low-Volatility Organic Compounds in Oxidation of Aromatics: Implications on Secondary Organic Aerosol.

Degree: 2016, University of Helsinki

URL: http://hdl.handle.net/10138/160851

►

A myriad of different volatile organic compounds is emitted to the atmosphere through biogenic and anthropogenic pathways. In the atmosphere, they get oxidised forming products… (more)

▼

A myriad of different volatile organic compounds is emitted to the atmosphere through biogenic and anthropogenic pathways. In the atmosphere, they get oxidised forming products of lower volatility, which may then condense and contribute to the formation and growth of aerosol particles. Extremely low-volatility organic compounds (ELVOC) is a group of highly oxidised molecules that were recently observed in oxidation of biogenically emitted molecules, monoterpenes. It has been shown that ELVOCs from monoterpene oxidation in the atmosphere explain most of the aerosol growth rates in the boreal forest. In this work, I investigate the ELVOC formation from aromatic compounds, which are primarily emitted from anthropogenic sources. This thesis focuses on oxidation of benzene, a simplest aromatic molecule, although ELVOCs forming from toluene, naphthalene and phenol are also presented. The experimental work with all compounds, except phenol, was conducted in a flow tube at the Universtity of Helsinki, Finland, while in-depth study of benzene was performed in the chamber at Forschungszentrum Jülich GmbH, Germany. The oxidation products were detected using nitrate-based scheme chemical ionisation atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-TOF). It was found that all four molecules in the reaction with a hydroxyl radical produced ELVOC. In case of benzene, the detected ELVOC monomers had maximum of 11 oxygen atoms, while dimers had up to 18. Toluene and naphthalene oxidation gained ELVOC monomers with maximum 10 oxygen atoms. The possibility of multiple reactions with the hydroxyl radical, however, could not be eliminated as the products of aromatic oxidation usually have higher reaction rate coefficients than their parent molecule. The average ELVOC molar yield in benzene oxidation was 3.7%, while in phenol case it was 1.5%, which suggested that primary OH attack and further autoxidation is an important pathway for ELVOC formation in oxidation of benzene. The study of the ELVOC – aerosol particle interactions in the chamber revealed that ELVOCs from aromatic precursors behave similarly to the ELVOCs formed from monoterpenes, rapidly condensing on the introduced aerosol particles. The organic fraction of the aerosols had similar O:C ratio to the total gas-phase ELVOC, indicating that ELVOCs were primary condensing species. The decreasing O:C ratio of aerosol phase with higher aerosol loading confirmed that ELVOCs are dominating aerosol growth at low aerosol loading. In this thesis, also a review of known chemical pathways of benzene oxidation is presented and some further steps towards ELVOC formation are suggested. Benzene oxidation pathways may serve as a model for studying the oxidation of other aromatic molecules. Substituted aromatic molecules are more reactive with the hydroxyl radical and are likely to yield more ELVOCs, which may be dominant factor in the aerosol growth in urban and industrialised areas.

Vain tiivistelmä. Opinnäytteiden arkistokappaleet ovat luettavissa Helsingin…

Subjects/Keywords: Atmosphere-Biosphere Studies

Record Details Similar Records Cite « Share

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

APA (6^th Edition):

Garmash, O. (2016). The Formation of Extremely Low-Volatility Organic Compounds in Oxidation of Aromatics: Implications on Secondary Organic Aerosol. (Thesis). University of Helsinki. Retrieved from http://hdl.handle.net/10138/160851

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):

Garmash, Olga. “The Formation of Extremely Low-Volatility Organic Compounds in Oxidation of Aromatics: Implications on Secondary Organic Aerosol.” 2016. Thesis, University of Helsinki. Accessed December 10, 2019. http://hdl.handle.net/10138/160851.

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

MLA Handbook (7^th Edition):

Garmash, Olga. “The Formation of Extremely Low-Volatility Organic Compounds in Oxidation of Aromatics: Implications on Secondary Organic Aerosol.” 2016. Web. 10 Dec 2019.

Vancouver:

Garmash O. The Formation of Extremely Low-Volatility Organic Compounds in Oxidation of Aromatics: Implications on Secondary Organic Aerosol. [Internet] [Thesis]. University of Helsinki; 2016. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10138/160851.

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

Council of Science Editors:

Garmash O. The Formation of Extremely Low-Volatility Organic Compounds in Oxidation of Aromatics: Implications on Secondary Organic Aerosol. [Thesis]. University of Helsinki; 2016. Available from: http://hdl.handle.net/10138/160851

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

University of Helsinki

25. Hickman, Brandon. Precipitation estimation in urban areas by employing a dense-network of weather radars.

Degree: 2016, University of Helsinki

URL: http://hdl.handle.net/10138/160857

►

The aim of this thesis is the development of the highest quality quantitative precipitation estimate (QPE) for the Helsinki urban area through the creation of… (more)

▼

The aim of this thesis is the development of the highest quality quantitative precipitation estimate (QPE) for the Helsinki urban area through the creation of a quality controlled multi-radar composite. Weather radars suffer from a number of errors, and these are typically compounded when located near urban areas. Through the use of radar calibration, and several quality control methods, the three Helsinki area's radars (Kerava, Kumpula, Vantaa) were composited and a blended QPE was created. The three C-band dual-polarimetric weather radars were calibrated through the self-consistency theory which relates Z, Zdr, to Kdp. The calibration was conducted over several summer days in 2014 for each radar, and all were found to be under-calibrated by about 2 dB. The influence of rain on top of the radome was also examined and found that wet radome attenuation can produce several dB offset in calibration. Composites of Z and Kdp used weights were created to correct for non-hydrometeor class, beam blockage, attenuation of the beam, radome attenuation, range, and ground clutter. Noise in Kdp from light rain is reduced through utilizing the self-consistency theory. Composited reflectivity created significant improvements by filling data gaps, reducing errors, as well as providing additional observations for each echo. However minor errors, such as multi-trip echoes and speckle proceeded to the composite. The blended QPE was created from the composite data to obtain the benefits of R(Kdp) in heavy rain and hail, while R(Z) was used in cases of light rain. Rain rate algorithms developed for the Helsinki climate were implemented to calculate the rain intensity for the selected precipitation type, which were determined through a series of threshold values obtained from literature. R(Kdp) allows better estimation in for heavy rain and hail because of being closer related to the hydrometers diameter as well as being immune to a number of errors present in Z. The QPE created in this project provides improved precipitation intensity due to the use of multiple corrected radars. This data can be used for improved urban run-off modeling, emergency warnings and weather forecasting. However the method presented here is only applicable for liquid/mixed liquid and hail precipitation because of the impact of frozen hydrometeor on the dual-polarimetric parameters. Additional quality control methods and different precipitation estimates would be required for winter time precipitation.

Vain tiivistelmä. Opinnäytteiden arkistokappaleet ovat luettavissa Helsingin yliopiston kirjastossa. Hae HELKA-tietokannasta (http://www.helsinki.fi/helka/index.htm).

Abstract only. The paper copy of the whole thesis is available for reading room use at the Helsinki University Library. Search HELKA online catalog (http://www.helsinki.fi/helka/index.htm).

Endast avhandlingens sammandrag. Pappersexemplaret av hela avhandlingen finns för läsesalsbruk i Helsingfors universitets bibliotek. Sök i HELKA-databasen (http://www.helsinki.fi/helka/index.htm).

Subjects/Keywords: Atmosphere-Biosphere Studies

Record Details Similar Records Cite « Share

❌

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

APA (6^th Edition):

Hickman, B. (2016). Precipitation estimation in urban areas by employing a dense-network of weather radars. (Thesis). University of Helsinki. Retrieved from http://hdl.handle.net/10138/160857

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):

Hickman, Brandon. “Precipitation estimation in urban areas by employing a dense-network of weather radars.” 2016. Thesis, University of Helsinki. Accessed December 10, 2019. http://hdl.handle.net/10138/160857.

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

MLA Handbook (7^th Edition):

Hickman, Brandon. “Precipitation estimation in urban areas by employing a dense-network of weather radars.” 2016. Web. 10 Dec 2019.

Vancouver:

Hickman B. Precipitation estimation in urban areas by employing a dense-network of weather radars. [Internet] [Thesis]. University of Helsinki; 2016. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10138/160857.

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

Council of Science Editors:

Hickman B. Precipitation estimation in urban areas by employing a dense-network of weather radars. [Thesis]. University of Helsinki; 2016. Available from: http://hdl.handle.net/10138/160857

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

Virginia Tech

26. Tiwari, Andrea Jean. Aerosolization and Atmospheric Transformation of Engineered Nanoparticles.

Degree: PhD, Civil and Environmental Engineering, 2014, Virginia Tech

URL: http://hdl.handle.net/10919/56664

► While research on the environmental impacts of engineered nanoparticles (ENPs) is growing, the potential for them to be chemically transformed in the atmosphere has been… (more)

▼ While research on the environmental impacts of engineered nanoparticles (ENPs) is growing, the potential for them to be chemically transformed in the atmosphere has been largely ignored. The overall objective of this work was to assess the atmospheric transformation of carbonaceous nanoparticles (CNPs). The research focuses on C₆₀ fullerene because it is an important member of the carbonaceous nanoparticle (CNP) family and is used in a wide variety of applications. The first specific objective was to review the potential of atmospheric transformations to alter the environmental impacts of CNPs. We described atmospheric processes that were likely to physically or chemically alter aerosolized CNPs and demonstrated their relevance to CNP behavior and toxicity in the aqueous and terrestrial environment. In order to investigate the transformations of CNP aerosols under controlled conditions, we developed an aerosolization technique that produces nano-scale aerosols without using solvents, which can alter the surface chemistry of the aerosols. We demonstrated the technique with carbonaceous (C₆₀) and metal oxide (TiO₂, CeO₂) nanoparticle powders. All resulting aerosols exhibited unimodal size distributions and mode particle diameters below 100 nm. We used the new aerosolization technique to investigate the reaction between aerosolized C₆₀ and atmospherically realistic levels of ozone (O₃) in terms of reaction products, reaction rate, and oxidative stress potential. We identified C₆₀O, C₆₀O2, and C₆₀O3 as products of the C₆₀-O3 reaction. We demonstrated that the oxidative stress potential of C₆₀ may be enhanced by exposure to O3. We found the pseudo-first order reaction rate to be 9 x 10⁻⁶ to 2 x 10⁻⁵ s⁻¹, which is several orders of magnitude lower than the rate for several PAH species under comparable conditions. This research has demonstrated that a thorough understanding of atmospheric chemistry of ENPs is critical for accurate prediction of their environmental impacts. It has also enabled future research in that vein by developing a novel technique to produce nanoscale aerosols from nanoparticle powders. Results of this research will help guide the formulation of appropriate environmental policy concerning the regulation of ENPs. Advisors/Committee Members: Marr, Linsey C. (committeechair), Vikesland, Peter J. (committee member), Hochella, Michael F. Jr. (committee member), Morris, John R. (committee member).

Subjects/Keywords: Aerosol; nanoparticle; atmosphere

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APA (6^th Edition):

Tiwari, A. J. (2014). Aerosolization and Atmospheric Transformation of Engineered Nanoparticles. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/56664

Chicago Manual of Style (16^th Edition):

Tiwari, Andrea Jean. “Aerosolization and Atmospheric Transformation of Engineered Nanoparticles.” 2014. Doctoral Dissertation, Virginia Tech. Accessed December 10, 2019. http://hdl.handle.net/10919/56664.

MLA Handbook (7^th Edition):

Tiwari, Andrea Jean. “Aerosolization and Atmospheric Transformation of Engineered Nanoparticles.” 2014. Web. 10 Dec 2019.

Vancouver:

Tiwari AJ. Aerosolization and Atmospheric Transformation of Engineered Nanoparticles. [Internet] [Doctoral dissertation]. Virginia Tech; 2014. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10919/56664.

Council of Science Editors:

Tiwari AJ. Aerosolization and Atmospheric Transformation of Engineered Nanoparticles. [Doctoral Dissertation]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/56664

University of Waikato

27. Ross, Joseph. A Review of the Dynamics and Oscillations of the Atmosphere .

Degree: 2012, University of Waikato

URL: http://hdl.handle.net/10289/6480

► The atmosphere is a complex, dynamic system and the weather depends on its state. There are many different phenomena that affect the state of the… (more)

Subjects/Keywords: fluid dynamics; atmosphere

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APA (6^th Edition):

Ross, J. (2012). A Review of the Dynamics and Oscillations of the Atmosphere . (Masters Thesis). University of Waikato. Retrieved from http://hdl.handle.net/10289/6480

Chicago Manual of Style (16^th Edition):

Ross, Joseph. “A Review of the Dynamics and Oscillations of the Atmosphere .” 2012. Masters Thesis, University of Waikato. Accessed December 10, 2019. http://hdl.handle.net/10289/6480.

MLA Handbook (7^th Edition):

Ross, Joseph. “A Review of the Dynamics and Oscillations of the Atmosphere .” 2012. Web. 10 Dec 2019.

Vancouver:

Ross J. A Review of the Dynamics and Oscillations of the Atmosphere . [Internet] [Masters thesis]. University of Waikato; 2012. [cited 2019 Dec 10]. Available from: http://hdl.handle.net/10289/6480.

Council of Science Editors:

Ross J. A Review of the Dynamics and Oscillations of the Atmosphere . [Masters Thesis]. University of Waikato; 2012. Available from: http://hdl.handle.net/10289/6480

Columbia University

28. Dwyer, John. Projected Changes in the Annual Cycle of Surface Temperature and Precipitation Due to Greenhouse Gas Increases.

Degree: 2014, Columbia University

URL: https://doi.org/10.7916/D8CN7248

► When forced with increasing greenhouse gases, global climate models project changes to the seasonality of several key climate variables. These include delays in the phase… (more)

▼ When forced with increasing greenhouse gases, global climate models project changes to the seasonality of several key climate variables. These include delays in the phase of surface temperature, precipitation, and vertical motion indicating maxima and minima occurring later in the year. The changes also include an increase in the amplitude (or annual range) of low-latitude surface temperature and tropical precipitation and a decrease in the amplitude of high-latitude surface temperature and vertical motion. The aim of this thesis is to detail these changes, understand the links between them and ultimately relate them to simple physical mechanisms. At high latitudes, all of the global climate models of the CMIP3 intercomparison suite project a phase delay and amplitude decrease in surface temperature. Evidence is provided that the changes are mainly driven by sea ice loss: as sea ice melts during the 21st century, the previously unexposed open ocean increases the effective heat capacity of the surface layer, slowing and damping the temperature response at the surface. In the tropics and subtropics, changes in phase and amplitude are smaller and less spatially uniform than near the poles, but they are still prevalent in the models. These regions experience a small phase delay, but an amplitude increase of the surface temperature cycle, a combination that is inconsistent with changes to the effective heat capacity of the system. Evidence suggests that changes in the tropics and subtropics are linked to changes in surface heat fluxes. The next chapter investigates the nature of the projected phase delay and amplitude increase of precipitation using AGCM experiments forced by SST perturbations representing idealizations of the changes in annual mean, amplitude, and phase as simulated by CMIP5 models. A uniform SST warming is sufficient to force both an amplification and a delay of the annual cycle of precipitation. The amplification is due to an increase in the annual mean vertical water vapor gradient, while the delay is linked to a phase delay in the annual cycle of the circulation. A budget analysis of this simulation reveals a large degree of similarity with the CMIP5 results. In the second experiment, only the seasonal characteristics of SST are changed. For an amplified annual cycle of SST there is an amplified annual cycle of precipitation, while for a delayed SST there is a delayed annual cycle of precipitation. Assuming that SST changes can entirely explain the seasonal precipitation changes, the AGCM simulations suggest that the annual mean warming explains most of the amplitude increase and much of the phase delay in the CMIP5 models. However, imperfect agreement between the changes in the SST-forced AGCM simulations and the CMIP5 coupled simulations suggests that coupled effects may play a significant role. Finally, the connections between changes in the seasonality of precipitation, temperature and circulation are studied in the tropics using models of varying complexity. These models…

Subjects/Keywords: Climatic changes; Atmosphere

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

APA (6^th Edition):

Dwyer, J. (2014). Projected Changes in the Annual Cycle of Surface Temperature and Precipitation Due to Greenhouse Gas Increases. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8CN7248

Chicago Manual of Style (16^th Edition):

Dwyer, John. “Projected Changes in the Annual Cycle of Surface Temperature and Precipitation Due to Greenhouse Gas Increases.” 2014. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D8CN7248.

MLA Handbook (7^th Edition):

Dwyer, John. “Projected Changes in the Annual Cycle of Surface Temperature and Precipitation Due to Greenhouse Gas Increases.” 2014. Web. 10 Dec 2019.

Vancouver:

Dwyer J. Projected Changes in the Annual Cycle of Surface Temperature and Precipitation Due to Greenhouse Gas Increases. [Internet] [Doctoral dissertation]. Columbia University; 2014. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D8CN7248.

Council of Science Editors:

Dwyer J. Projected Changes in the Annual Cycle of Surface Temperature and Precipitation Due to Greenhouse Gas Increases. [Doctoral Dissertation]. Columbia University; 2014. Available from: https://doi.org/10.7916/D8CN7248

Columbia University

29. Nakamura, Jennifer Anne. Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean.

Degree: 2014, Columbia University

URL: https://doi.org/10.7916/D86H4FM1

► This study explores seasonal patterns and structures of moisture transport pathways from the North Atlantic Ocean and the Gulf of Mexico that lead to extreme… (more)

▼ This study explores seasonal patterns and structures of moisture transport pathways from the North Atlantic Ocean and the Gulf of Mexico that lead to extreme large-scale precipitation and floods over land. Storm tracks, such as the tropical cyclone tracks in the Northern Atlantic Ocean, are an example of moisture transport pathways. In the first part, North Atlantic cyclone tracks are clustered by the moments to identify common traits in genesis locations, track shapes, intensities, life spans, landfalls, seasonal patterns, and trends. The clustering results of part one show the dynamical behavior differences of tropical cyclones born in different parts of the basin. Drawing on these conclusions, in the second part, statistical track segment model is developed for simulation of tracks to improve reliability of tropical cyclone risk probabilities. Moisture transport pathways from the North Atlantic Ocean are also explored though the specific regional flood dynamics of the U.S. Midwest and the United Kingdom in part three of the dissertation. Part I. Classifying North Atlantic Tropical Cyclones Tracks by Mass Moments. A new method for classifying tropical cyclones or similar features is introduced. The cyclone track is considered as an open spatial curve, with the wind speed or power information along the curve considered as a mass attribute. The first and second moments of the resulting object are computed and then used to classify the historical tracks using standard clustering algorithms. Mass moments allow the whole track shape, length and location to be incorporated into the clustering methodology. Tropical cyclones in the North Atlantic basin are clustered with K-means by mass moments producing an optimum of six clusters with differing genesis locations, track shapes, intensities, life spans, landfalls, seasonality, and trends. Even variables that are not directly clustered show distinct separation between clusters. A trend analysis confirms recent conclusions of increasing tropical cyclones in the basin over the past two decades. However, the trends vary across clusters. Part II: Tropical cyclone Intensity and Track Simulator (HITS) with Atlantic Ocean Applications for Risk Assessment. A nonparametric stochastic model is developed and tested for the simulation of tropical cyclone tracks. Tropical cyclone tracks demonstrate continuity and memory over many time and space steps. Clusters of tracks can be coherent, and the separation between clusters may be marked by geographical locations where groups of tracks diverge due to the physics of the underlying process. Consequently, their evolution may be non-Markovian. Markovian simulation models, as often used, may produce tracks that potentially diverge or lose memory quicker than nature. This is addressed here through a model that simulates tracks by randomly sampling track segments of varying length, selected from historical tracks. For performance evaluation, a spatial grid is imposed on the domain of interest. For each grid…

Subjects/Keywords: Atmosphere; Hydrology; Statistics

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APA (6^th Edition):

Nakamura, J. A. (2014). Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D86H4FM1

Chicago Manual of Style (16^th Edition):

Nakamura, Jennifer Anne. “Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean.” 2014. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D86H4FM1.

MLA Handbook (7^th Edition):

Nakamura, Jennifer Anne. “Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean.” 2014. Web. 10 Dec 2019.

Vancouver:

Nakamura JA. Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean. [Internet] [Doctoral dissertation]. Columbia University; 2014. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D86H4FM1.

Council of Science Editors:

Nakamura JA. Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean. [Doctoral Dissertation]. Columbia University; 2014. Available from: https://doi.org/10.7916/D86H4FM1

Columbia University

30. Yang, Wenchang. The Hydroclimate of East Africa: Seasonal cycle, Decadal Variability, and Human induced Climate Change.

Degree: 2015, Columbia University

URL: https://doi.org/10.7916/D8J96547

► The hydroclimate of East Africa shows distinctive variabilities on seasonal to decadal time scales and poses a great challenge to climatologists attempting to project its… (more)

▼ The hydroclimate of East Africa shows distinctive variabilities on seasonal to decadal time scales and poses a great challenge to climatologists attempting to project its response to anthropogenic emissions of greenhouse gases (GHGs). Increased frequency and intensity of droughts over East Africa in recent decades raise the question of whether the drying trend will continue into the future. To address this question, we first examine the decadal variability of the East African rainfall during March to May (MAM, the major rainy season in East Africa) and assess how well a series of models simulate the observed features. Observational results show that the drying trend during MAM is associated with decadal natural variability of sea surface temperature (SST) variations over the Pacific Ocean. The multimodel mean of the SST forced, Coupled Model Intercomparison Project Phase 5 (CMIP5) AMIP experiment models reproduces both the climatological annual cycle and the drying trend in recent decades. The fully coupled models from the CMIP5 historical experiment, however, have systematic errors in simulating the East African rainfall annual cycle by underestimating the MAM rainfall while overestimating the October to December (OND, the second rainy season in East Africa) rainfall. The multimodel mean of the historical coupled runs of the MAM rainfall anomalies, which is the best estimate of the radiatively forced change, shows a weak wetting trend associated with anthropogenic forcing. However, the SST anomaly pattern associated with the MAM rainfall has large discrepancies with the observations. The errors in simulating the East African hydroclimate with coupled models raise questions about how reliable model projections of future East African climate are. This motivates a fundamental study of why East African climate is the way it is and why coupled models get it wrong. East African hydroclimate is characterized by a dry annual mean climatology compared to other deep tropical land areas and a bimodal annual cycle with the major rainy season during MAM (often called the ``long rains'' by local people) and the second during OND (the ``short rains''). To explore these distinctive features, we use the ERA Interim Re Analysis data to analyze the associated annual cycles of atmospheric convective stability, circulation and moisture budget. The atmosphere over East Africa is found to be convectively stable, in general, year round but with an annual cycle dominated by the surface moist static energy (MSE), which is in phase with the precipitation annual cycle. Throughout the year, the atmospheric circulation is dominated by a pattern of convergence near the surface, divergence in the lower troposphere and convergence again at upper levels. Consistently, the convergence of the vertically integrated moisture flux is mostly negative across the year, but becomes weakly positive in the two rainy seasons. It is suggested the semi-arid/arid climate in East Africa and its bimodal rainfall annual cycle can be explained by…

Subjects/Keywords: Atmosphere; Climatic changes

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

APA (6^th Edition):

Yang, W. (2015). The Hydroclimate of East Africa: Seasonal cycle, Decadal Variability, and Human induced Climate Change. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D8J96547

Chicago Manual of Style (16^th Edition):

Yang, Wenchang. “The Hydroclimate of East Africa: Seasonal cycle, Decadal Variability, and Human induced Climate Change.” 2015. Doctoral Dissertation, Columbia University. Accessed December 10, 2019. https://doi.org/10.7916/D8J96547.

MLA Handbook (7^th Edition):

Yang, Wenchang. “The Hydroclimate of East Africa: Seasonal cycle, Decadal Variability, and Human induced Climate Change.” 2015. Web. 10 Dec 2019.

Vancouver:

Yang W. The Hydroclimate of East Africa: Seasonal cycle, Decadal Variability, and Human induced Climate Change. [Internet] [Doctoral dissertation]. Columbia University; 2015. [cited 2019 Dec 10]. Available from: https://doi.org/10.7916/D8J96547.

Council of Science Editors:

Yang W. The Hydroclimate of East Africa: Seasonal cycle, Decadal Variability, and Human induced Climate Change. [Doctoral Dissertation]. Columbia University; 2015. Available from: https://doi.org/10.7916/D8J96547

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