Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, December 1994. / "December 1994." Thesis advisor(s): Teddy R. Holt. Bibliography: p. 79-81. Also available online.

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 21, 2007) Includes bibliographical references.

No description available.

Orientador: Anderson Luís Hebling Christofoletti / Banca: Jussara dos Santos Rosendo / Banca: Diego Correa Maia / Resumo: As inundações constituem um dos impactos ambientais mais observados nas áreas urbanas. A incidência destes eventos varia conforme as características climáticas e socioambientais das cidades. Esta pesquisa teve como objetivo principal avaliar o risco a enchentes, a alagamentos e ao escoamento superficial concentrado na área urbana de Ituiutaba (MG), a partir de suas condicionantes físicas e de suas características socioespaciais, inerentes ao processo de urbanização. Para isto, realizaram-se análises do geossistema urbano; da variabilidade pluvial com enfoque na recorrência das precipitações extremas; das ocorrências de transtornos associados ao impacto pluvial e da percepção do problema por parte da população atingida e do poder público municipal. Verificou-se que os impactos hidrometeóricos concentram-se durante os meses da primavera e do verão, quando as chuvas são mais abundantes. Em média, treze episódios chuvosos com volume a partir de 30mm/24h acontecem a cada ano, representando, assim, um potencial de danos ao ambiente urbano. De forma mais esporádica, acontecem ainda precipitações mais intensas, por volta de 90mm/24h, com potencial de impacto muito maior. Os arquivos das ocorrências do Corpo de Bombeiros e as reportagens publicadas pela imprensa local constituíram importantes fontes para o mapeamento e análise dos impactos. Como consequência desses eventos, tem-se na área central da cidade e bairros adjacentes, que são mais impermeabilizados, as ocorrências de escoame... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Floods are one of the most observed environmental impacts in urban areas. The incidence of these events varies according to the climatic and socio-environmental characteristics of the cities. The main objective of this research was to evaluate the risk to the overflows, the floods and the concentrated surface runoff in the urban area of Ituiutaba (MG), based on its physical conditioning aspects and its socio-spatial characteristic, which are inherent in the urbanization process. For that purpose, some analyzes of the urban geosystem, the rainfall variability with focus on the recurrence of the extreme precipitations, the occurrences of disturbances associated with the rainfall impact and the perception of the problem by the affected population and the municipal public power were carried out. It was found that the hydrometeoric impacts are concentrated in the spring and summer months, when the rains are more abundant. On average, thirteen rainy episodes with a volume from 30mm/24h happen each year, which represents a potential for damages to the urban environment. More sporadically, there are some intense precipitations, around 90mm/24h, with a much greater potential impact. The Fire Department's archives and the news published in the local press were important sources for the mapping and analysis of the impacts. As a consequence of these events, there are in the city centre area and adjacent neighborhoods, which are more waterproofed spaces, the occurrences of concentrated su... (Complete abstract click electronic access below) / Mestre

Rapid urbanization of cities has greatly modified the thermal and dynamic profile in the urban boundary layer. This thesis attempts to study the effect of urban heating on the local climate and air quality for a tropical coastal urban agglomeration, Greater Kuala Lumpur (GKL) in Malaysia. A state-of-art numerical model, Weather Research and Forecast Model (WRF) is used to identify the influence of urbanization through modification of urban surfaces. In order to thoroughly study the environmental impact of land use change in GKL, this thesis begins with the local urban heating on the surface layer before extending to the influence on the boundary layer circulation and its atmospheric composition. The WRF model is tested for its applicability to reproduce the urban heating condition. The model verification hence incorporates sensitivity analysis of physics pertinent to the simulation of land surface and boundary layer dynamics condition, namely the land use map, urban canopy model (UCM) and planetary boundary layer (PBL) physics options. Result shows that the urban surface representation and parameterization models in WRF are of great importance for the high resolution urban climate in the region. The locally calibrated land use map and urban parameters have substantially improved the near-surface weather and urban heating prediction. The local PBL scheme also predicts a generally good agreement for the studied region in terms of near-surface environment and vertical profile during the morning and evening transitional period. Incorporating the optimum physics settings, the control study found that urbanization due to land use change has induced a modelled daily mean urban heat island intensity (UHII) of 0.9 °C with a more severe heating of 1.9 °C at night. The heating condition induces urban thermal circulation that interacts with the local topographic flow, namely sea/land breeze and downhill/uphill breeze for the coastal urban agglomeration sheltered by the mountain ranges on the other side. Depending on the cloud cover and prevailing synoptic flow, the immense heat forcing on the surface accelerates/decelerates the moisture-bearing sea breeze during the day. It also induces vertical lifting which creates a conducive environment for convective precipitation on the upwind region. The subsequent control study with chemical weather prediction model (WRF-Chem) shows that the urban heating condition reduces the ground ozone level by around 20 ppbv throughout the day. Analysis shows that the reduced ozone level is closely correlated to the stronger horizontal sea breeze front (SBF) advection in the morning and urban-enhanced vertical mixing during the night which disperse the ground ozone and its precursors. Despite the reduction of ozone level, the air quality monitoring result identifies GKL as NOx-sensitive region which is prone to higher level of ozone with the continuous expansion of urban. The thesis explores the ability of WRF software to reproduce the high resolution urban climate. The model evaluation has realistically discovered that WRF is able to produce good approximation of the near-surface weather condition and fairly reasonable vertical boundary layer profiles. However, the atmospheric chemistry composition of the local surface pollutants is greatly underestimated. Continuous effort is required to improve the regional prediction on the chemistry weather prediction tool.

Ice accretion on aerofoils is a problematic phenomenon affecting power lines, ships and aircraft wings. This work thus undertakes an experimental and computational investigation into the formation and adhesion of ice on aerofoils. An experimental setup to test the adhesion strength of ice was designed and tested for repeatability and the effect of temperature on it. It was found that the ambient temperature has a profound effect on the adhesion strength, possibly due to dependence on the heat transfer mechanism through an amorphous liquid-like layer between ice and substrate. The tests were expanded to determine the effect of contact angle parameters on the icephobicity of 14 nanocoatings. It was found that the surface should possess high receding contact angle and low CAH to reduce adhesion thereby reducing the ice-substrate contact points. Hydrophobicity and icephobicity may not necessarily be dual characteristics of a surface unless the aforementioned criteria is satisfied. Anti-icing tests on the same coatings showed that the freezing time of a droplet on the surface reduces with an increase in static contact angle. To understand the role of mixed ice, a one dimensional model is introduced to measure the accretion of mixed, rime and glaze ice on an aerofoil. This process occurs in four distinct stages and the effect of atmospheric parameters on the transition time between different growth types and height is determined. This mode was developed further to include a convective term to determine the profile of ice when rime grows above glaze/mixed with water flowing inside. This is a first step towards understanding the links between porous structures, ice structures and runback water that can generate interesting icy structures. This work forms part of the ICECOAT project funded by the EU Framework 7 CleanSky programme under grant award JTI-CS-2012-02-SFWA-01-051.

abstract: Metropolitan Phoenix, Arizona, is one of the most rapidly urbanizing areas in the U.S., which has resulted in an urban heat island (UHI) of substantial size and intensity. Several detrimental biophysical and social impacts arising from the large UHI has posed, and continues to pose, a challenge to stakeholders actively engaging in discussion and policy formulation for a sustainable desert city. There is a need to mitigate some of its detrimental effects through sustainable methods, such as through the application of low-water, desert-adapted low-water use trees within residential yards (i.e. urban xeriscaping). This has the potential to sustainably reduce urban temperatures and outdoor thermal discomfort in Phoenix, but evaluating its effectiveness has not been widely researched in this city or elsewhere. Hence, this dissertation first evaluated peer-reviewed literature on UHI research within metropolitan Phoenix and discerned several major themes and factors that drove existing research trajectories. Subsequently, the nocturnal cooling influence of an urban green-space was examined through direct observations and simulations from a microscale climate model (ENVI-Met 3.1) with an improved vegetation parameterization scheme. A distinct park cool island (PCI) of 0.7-3.6 °C was documented from traverse and model data with larger magnitudes closer to the surface. A key factor in the spatial expansion of PCI was advection of cooler air towards adjacent urban surfaces, especially at 0-1 m heights. Modeled results also possessed varying but reasonable accuracy in simulating temperature data, although some systematic errors remained. Finally, ENVI-Met generated xeriscaping scenarios in two residential areas with different surface vegetation cover (mesic vs. xeric), and examined resulting impacts on near-surface temperatures and outdoor thermal comfort. Desert-adapted low-water use shade trees may have strong UHI mitigation potential in xeric residential areas, with greater cooling occurring at (i.) microscales (~2.5 °C) vs. local-scales (~1.1 °C), and during (ii.) nocturnal (0500 h) vs. daytime periods (1700 h) under high xeriscaping scenarios. Conversely, net warming from increased xeriscaping occurred over mesic residential neighborhoods over all spatial scales and temporal periods. These varying results therefore must be considered by stakeholders when considering residential xeriscaping as a UHI mitigation method. / Dissertation/Thesis / Ph.D. Geography 2011

Data assimilation plays an important role in weather forecasting. The purpose of data assimilation is try to provide a more accurate atmospheric state for future forecast. Several existed methods currently used in this field fall into two categories: statistical data assimilation and variational data assimilation. This thesis focuses mainly on variational data assimilation. The original objective function of three dimensional data assimilation (3D-VAR) consists of two terms: the difference between the pervious forecast and analysis and the difference between the observations and analysis in observation space. Considering the inaccuracy of previous forecasting results, we replace the first term by the difference between the previous forecast gradients and analysis gradients. The associated data fitting term can be interpreted using the second-order finite difference matrix as the inverse of the background error covariance matrix in the 3D-VAR setting. In our approach, it is not necessary to estimate the background error covariance matrix and to deal with its inverse in the 3D-VAR algorithm. Indeed, the existence and uniqueness of the analysis solution of the proposed objective function are already established. Instead, the solution can be calculated using the conjugate gradient method iteratively. We present the experimental results based on WRF simulations. We show that the performance of this forecast gradient based DA model is better than that of 3D-VAR. Next, we propose another optimization method of variational data assimilation. Using the tensor completion in the cost function for the analysis, we replace the second term in the 3D-VAR cost function. This model is motivated by a small number of observations compared with the large portion of the grids. Applying the alternating direction method of multipliers to solve this optimization problem, we conduct numerical experiments on real data. The results show that this tensor completion based DA model is competitive in terms of prediction accuracy with 3D-VAR and the forecast gradient based DA model. Then, 3D-VAR and the two model proposed above lack temporal information, we construct a third model in four-dimensional space. To include temporal information, this model is based on the second proposed model, in which introduce the total variation to describe the change of atmospheric state. To this end, we use the alternating direction method of multipliers. One set of experimental results generates a positive performance. In fact, the prediction accuracy of our third model is better than that of 3D-VAR, the forecast gradient based DA model, and the tensor completion based DA model. Nevertheless, although the other sets of experimental results show that this model has a better performance than 3D-VAR and the forecast gradient based DA model, its prediction accuracy is slightly lower than the tensor completion based model.

Orientador: João Afonso Zavattini / Banca: Anderson Luis Hebling Christofoletti / Banca: Marcos Norberto Boin / Resumo: A erosão hídrica é um dos impactos ambientais que mais preocupam, na atualidade, o Brasil. Na era das cruzadas pró-ambientais, devido ao uso exacerbado dos recursos naturais, dentre eles o solo, este tipo de erosão tem sido investigada por várias áreas do conhecimento científico. Dentre elas, a Climatologia aparece como de suma importância ao conhecimento processual do fenômeno, mesmo havendo poucos estudos na área. Deste modo, aqui, através do estudo do comportamento da chuva e da erosividade na bacia hidrográfica do rio Jordão-PR, buscou-se traçar um panorama sobre a implicação erosiva das chuvas na área de estudo. Os dados pluviométricos foram coletados junto ao Instituto de Águas do Paraná e os dados meteorológicos junto ao Sistema Meteorológico Paranaense (SIMEPAR). Com Base nestes dados foi realizada a caracterização da chuva para o período que compreende o segmento 1977-2007 e, através desta análise, foram selecionados três anos padrão, sejam eles o chuvoso (1998), habitual (2005) e seco (2006) com vistas ao estudo da climatologia dinâmica. Assim, foi realizada, para a cidade de Guarapuava-PR, a análise rítmica dos tipos de tempo nos meses de abril e dezembro, os mais impactantes nos três anos padrão analisados. Concluiu-se que os tipos de tempo geradores de chuva na área de estudo, nestes meses, são a Frente Polar Atlântica e as Áreas de Instabilidade Tropicais. Também se verificou que a área está sujeita a dois tipos de processos erosivos determinados pela chuva e que estes estão sujeitos à dinâmica dos tipos de tempo a nível regional / Abstract: Water erosion is one of the environmental impacts of most concern, nowadays, Brazil. In the era of the crusades pro-environment, exacerbated by the use of natural resources, including soil, this type of erosion has been investigated by several areas of scientific knowledge. Among them, Climatology appears as paramount to the procedural knowledge of the phenomenon, even though there are few studies in the area. Thus, here, through the study of the behavior and the erosivity of rain in the catchment area of the River Jordão-PR, we tried to give an overview on the impact of erosive rainfall in the study area. The rainfall data were collected by the Water Institute of Paraná and meteorological data by the Meteorological System Paranaense (SIMEPAR). Based on these data was performed to characterize the rainfall for the period 1977-2007 and includes the segment, through this analysis, we selected three years standard, whether the rainy season (1998), habitual (2005) and dry (2006) with views the study of dynamic climatology. Thus, it was held, to the city of Guarapuava-PR, the analysis of rhythmic types of weather in the months of april and december, the most striking pattern in the three years analyzed. It was concluded that the types of weather generators rain in the study area, these months are the Polar Front and the Atlantic Tropical Areas of Instability. It was also found that the area is subject to two types of erosion by rain and determined that they are subject to the dynamics of the types of time at regional level / Mestre