RESUMO Neste trabalho, a origem dos Jatos de Baixos Níveis (JBN) noturnos de Iperó (SP) e o seu papel na dispersão de poluentes no Estado de São Paulo são investigados. Para tanto são utilizados os dados coletados nas quatro campanhas de medidas em Iperó. Utilizou-se também um modelo numérico de mesoescala não-hidrostático TVM para simular a estrutura espacial 3-D do JBN em resposta as forçantes topográficas e associadas ocupação da superfície. Os resultados observacionais indicam que o JBN ocorre em Iperó com bastante freqüência nas noites de céu claro, com intensidade variando entre 8 e 10 m/s e localizado em torno de 350 m acima da superfície. Os JBNs em Iperó caracterizam-se por um cisalhamento direcional, com ventos de SE na superfície e de ENE na região de máximo. Ocorrem tanto no inverno como no verão, e afetam o ciclo diurno médio do vento observado nos primeiros 100 metros na região de Iperó. Os JBNs são responsáveis pelo máximo noturno (21:00 HL) existente no ciclo diurno médio do vento na região. Os resultados numéricos indicam que o JBN de Iperó é resultado da ação combinada de quatro fatores: (1) circulação anabática no setor paulista do vale do Rio Paraná; (2) oscilação inercial; (3) circulação catabática noturna e (4) brisa marítima. Estes quatro fatores combinados sustentam um JBN com intensidade de 5 a 10 m/s, localizados a uma altitude de 100 a 400 m acima da superfície, durante maior parte da noite. O JBN simulado numericamente encontra-se localizado no setor oeste da região de convergência da circulação anabática e da brisa marítima. Esta região de convergência em baixos níveis se forma durante o dia na parte mais elevada do Estado de São Paulo que acompanha da linha do litoral (Serra do Mar e da Cantareira). O efeito do JBN sobre o transporte de poluente foi investigado com um modelo Lagrangiano de dispersão de partículas. Verificou-se que o JBN aumenta a dispersão horizontal das partículas, transportando o poluente atmosférico emitido na superfície até 250 km da fonte. / ABSTRACT This work investigates the nocturnal Low-Level Jet (LLJ) in Iperó, Brazil, and its role in the pollutant dispersion on the State of São Paulo (SP). Data of four field campaigns in Iperó-SP was used in this investigation. A mesoscale and non-hydrostatic TVM model is also used to simulate the 3D structure of the LLJ, which is a dynamic response to topography and land use. The observational results indicate that the LLJ is frequently found during clear air nights, with a maximum between 8 and 10 m s–1, located around 350 m above surface. The LLJ in Iperó is characterized by a directional wind shear, with SE winds near surface and ENE near to the maximum. They occur during the winter and summer, and can modify the diurnal cycle of the mean wind in the first 100 m in the Iperó area. The LLJ are responsible by the nocturnal maximum (21:00 LT) in the mean wind in Iperó. The numerical results indicate the Iperó LLJ is a result of four factors: (1) anabatic circulation in São Paulo sector of the Paraná River Basin; (2) inertial oscillation; (3) nocturnal katabatic circulation and (4) sea breeze. These factors, together, sustain a LLJ with jet core intensity between 5 and 10 m/s, located between 100 and 400 m above surface during the major of nighttime period. The simulated LLJ numerically is found in the west sector in the convergence zone of the anabatic and sea breeze circulations. This convergence flow area appears during the daytime above the more elevated areas in the State of São Paulo, i.e., along mountains aligned parallel to coastline (Serra do Mar and Cantareira). The effects of the LLJ in a pollutant transport were investigated using a Lagrangian Particle Dispersion model coupled to the mesoscale model TVM. The results show that the LLJ increases the horizontal dispersion of the particles released near surface in Iperó and is able to transport the pollutant up to 250 km downwind the source.

Submitted by Cátia Araújo (catia.araujo@unipampa.edu.br) on 2017-01-25T11:32:18Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Um modelo para dispersão de poluentes na camada limite planetária com coeficientes de difusão dependentes da distância da fonte.pdf: 1813716 bytes, checksum: 2b7788e4583766741e3b5c4e7ae8da30 (MD5) / Approved for entry into archive by Cátia Araújo (catia.araujo@unipampa.edu.br) on 2017-01-25T11:33:16Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Um modelo para dispersão de poluentes na camada limite planetária com coeficientes de difusão dependentes da distância da fonte.pdf: 1813716 bytes, checksum: 2b7788e4583766741e3b5c4e7ae8da30 (MD5) / Made available in DSpace on 2017-01-25T11:33:16Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Um modelo para dispersão de poluentes na camada limite planetária com coeficientes de difusão dependentes da distância da fonte.pdf: 1813716 bytes, checksum: 2b7788e4583766741e3b5c4e7ae8da30 (MD5) Previous issue date: 2013-07-15 / Este trabalho apresenta a solução da equação da difusão-advecção bidimensional estacionária para simular a dispersão de poluentes na Camada Limite Planetária. A solução é obtida através do método ADMM (Analytical Dispersion Multilayer Model) e da técnica de inversão numérica utilizando o algoritmo de Fixed Talbot. A validação da solução é comprovada, mediante os parâmetros estatísticos, através do confrontamento das concentrações calculadas a partir do modelo com as obtidas experimentalmente pelo experimento de Prairie Grass. Para a determinação das concentrações utiliza-se o perfil do vento segundo o modelo de similaridade de Monin-Obukhov e os parâmetros de turbulência com dependência da distância longitudinal da fonte e da altura vertical, considerando a componente vertical do espectro Euleriano e de acordo com o modelo sugerido por Hɸjstrup que divide os espectros em alta e baixa frequência. Para efeito comparativo utiliza-se um coeficiente de difusão para grandes tempos de difusão. Os melhores resultados foram alcançados com a utilização dos coeficientes de difusão considerando a distância longitudinal da fonte e a altura vertical. / This work presents the solution of two-dimensional advection-diffusion equation stationary to simulate the dispersion of pollutants in the Planetary Boundary Layer. The solution is obtained through the ADMM method (Analytical Multilayer Dispersion Model) and the numerical inversion technique using the algorithm Fixed Talbot. Validation of the solution is proven, statistical parameters, through the confrontation of the concentrations calculated from the model with those obtained experimentally by the Experiment of Prairie Grass. For the determination of the concentration profile of the wind the form of Monin-Obukhov similarity and turbulence parameters with longitudinal distance dependence of source and of vertical height, considering the vertical component of the Eulerian spectrum and according to the model proposed by Hɸjstrup that divides the high and low frequency spectra. To use the comparative effect diffusion coefficient for large diffusion times according. The best results were achieved with the use of diffusion coefficients considering the longitudinal distance from the source and the vertical height.

Changing land cover from prairie grasslands to intensive, primarily cereal agriculture, over the North American Great Plains since the mid-19th century, has had a hydrological and climatological impact on that ecosystem (Pielke, Sr., et al., 2011). Agriculture has introduced timed harvest seasons, irrigation, and C3 photosynthesizing crops with poorer water efficiency than the grasses it replaced. All of these changes have been linked to exacerbated drought conditions and warmer temperatures; however, few studies have quantified this relationship at the continental scale. In order to evaluate the change imposed by this shift in land use and land cover, the observation based 20th Century Reanalysis Project (20CR) was used to quantify the climatological differences in temperature and humidity between areas of natural prairie and agriculture over the 20th century. An additional analysis used the Observation Minus Reanalysis (OMR) technique to isolate the surface climate signal found in the 20CR. We find indications that changing land cover had an impact on climate. However, using observation based data returned no evidence of a statistically significant change due to the small land use and land cover change (LULCC) signal within the larger climate noise. Therefore, an idealised modelling experiment was undertaken using the Geophysical Fluid Dynamics Laboratory (GFDL) AM2-LM2 atmosphere-land model to remove these other influences. This experiment compared the results of two model simulations: one where the entirety of the prairie was preserved as grassland (GRASS), and another where the entire prairies had been converted into an agricultural area (AGRIC). Relative to GRASS, the AGRIC simulation has reduced surface albedo and root zone depth, and increased roughness length over the prairies, which collectively cause a significant summer drying. This occurs when the shallower rooting zone limited potential evapotranspiration (PET) forcing the additional energy created by turbulent mixing and a lower surface albedo to warm the air, surpassing PET and reaching drier conditions faster. While not conclusive, the results presented in this thesis represent a step towards filling the gaps in understanding land-atmosphere interactions and connecting LULCC to climate.

Existe uma variedade de modelos de dispersão de poluentes, em geral, os modelos gaussianos são usados em todo o mundo por agências ambientais com intuito de regulação. O modelo CALPUFF é um deles. Neste estudo, _e avaliada a influência de escalas de tempo de descorrelação no sistema de modelagem CALPUFF, sob condições atmosféricas neutras. Para fazer isso uma nova parametrização das escalas de tempo descorrelação é proposta. Uma distribuição espectral de um perfil de velocidade euleriana e uma for- mutação da evolução das escalas temporais de descorrelação Lagrangiana são utilizadas como os mecanismos forçantes na dispersão turbulenta, numa camada limite dominada pelo cisalhamento do vento. O desempenho do modelo foi estabelecido com a comparação das concentrações superficiais do experimento Over-Land Alongwind Dispersion. Emissões de fontes em linha foram avaliadas com o modelo CALPUFF com distintas formas de inicialização. Um segundo modelo também foi testado, normalmente utilizado para estudar e prever o impacto ambiental e validar parametrizações turbulentas. É o modelo estocástico de partículas Lagrangiano LAMBDA. Também neste estudo, os resultados do modelo LAMBDA e CALPUFF enfatizam a capacidade da nova derivação de escalas de tempo em representar o comportamento estocástico desconhecido do fenômeno da dispersão de poluentes. / There exists a variety of pollution of dispersion models and in general, Gaussian models are used worldwide by environmental agencies in regulatory applications. The CALPUFF model is one of them. In this study, the in uence of decorrelation time scales in the CALPUFF modeling system under neutral conditions is evaluated. To do this a new parameterization of decorrelation time scales is proposed. A spectral distribution of an Eulerian velocity pro le and a formulation of the evolution of the Lagrangian decorrela- tion timescales are used as the forcing mechanisms (shear-dominated boundary layer) for the turbulent dispersion. The model performance was established by comparing ground- level concentrations with Over-Land Alongwind Dispersion experimental results. Line source emissions was evaluated using the CALPUFF model with different forms of the initialization. A second model was also tested, normally used to study and predict the environmental impact and validate turbulent parameterizations. Is the stochastic La- grangian dispersion model LAMBDA (Ferrero and Anfossi, 1998). Also in this study the model LAMBDA and CALPUFF results emphasized the ability of the new derivation of decorrelation time scales to represent the unknown stochastic behavior.

On January 29-30, 2008 a squall line of thunderstorms moved through the Ohio Valley resulting in four deaths and one injury. Such events highlight the importance of accurate forecasting for public safety. Mesoscale Modeling plays an important role in any forecast of a potential squall line. The focus of this study was to examine the performance of several parameterization scheme combinations in the Weather Research and Forecasting Model version three (WRF) as they related to this event. These examinations included cloud microphysics (WRF Single-Moment 3-class, 6-class, and Goddard), cumulus parameterization (Kain-Fritsch and Bets-Miller-Janjic) and planetary boundary layer schemes (Yonsei-University and Mellor-Yamada-Janjic). A total of 12 WRF simulations were conducted for all potential scheme combinations. Data from the WRF simulations for several locations in south central Kentucky were analyzed and compared using Kentucky Mesonet observations for four locations: Bowling Green, Russellville, Murray and Liberty, KY. A fine model resolution of 1 km was used over these locations. Coarser resolutions of 3 km and 9 km were used on the outer two domains, which encompassed the Ohio and Tennessee Valleys. The model simulation performance was assessed using established statistical measures for the above four locations and by visually comparing the North American Regional Reanalysis dataset (NARR) along with modeled simulations. The most satisfactory scheme combination was the WRF Single-Moment 3-class Microphysics scheme, Kain-Fritsch cumulus parameterization scheme and Yonsei University scheme for the planetary boundary layer. The planetary boundary layer schemes were noted to have the greatest influence in determining the most satisfactory model simulations. There was limited influence from different selections of microphysics and cumulus parameterization schemes. The preferred physics parameters from these simulations were then used in six additional simulations to analyze the affect different initialization data sets have with regards to model output. Data sets used in these simulations were the Final Operational Analysis global data, North American Regional Reanalysis (3 and 6 hour) and the North American Mesoscale Model at 1, 3 and 6 hour timesteps, for a total of six simulations. More timesteps or an increase in model resolution did not materially improve the model performance.

Existe uma variedade de modelos de dispersão de poluentes, em geral, os modelos gaussianos são usados em todo o mundo por agências ambientais com intuito de regulação. O modelo CALPUFF é um deles. Neste estudo, _e avaliada a influência de escalas de tempo de descorrelação no sistema de modelagem CALPUFF, sob condições atmosféricas neutras. Para fazer isso uma nova parametrização das escalas de tempo descorrelação é proposta. Uma distribuição espectral de um perfil de velocidade euleriana e uma for- mutação da evolução das escalas temporais de descorrelação Lagrangiana são utilizadas como os mecanismos forçantes na dispersão turbulenta, numa camada limite dominada pelo cisalhamento do vento. O desempenho do modelo foi estabelecido com a comparação das concentrações superficiais do experimento Over-Land Alongwind Dispersion. Emissões de fontes em linha foram avaliadas com o modelo CALPUFF com distintas formas de inicialização. Um segundo modelo também foi testado, normalmente utilizado para estudar e prever o impacto ambiental e validar parametrizações turbulentas. É o modelo estocástico de partículas Lagrangiano LAMBDA. Também neste estudo, os resultados do modelo LAMBDA e CALPUFF enfatizam a capacidade da nova derivação de escalas de tempo em representar o comportamento estocástico desconhecido do fenômeno da dispersão de poluentes. / There exists a variety of pollution of dispersion models and in general, Gaussian models are used worldwide by environmental agencies in regulatory applications. The CALPUFF model is one of them. In this study, the in uence of decorrelation time scales in the CALPUFF modeling system under neutral conditions is evaluated. To do this a new parameterization of decorrelation time scales is proposed. A spectral distribution of an Eulerian velocity pro le and a formulation of the evolution of the Lagrangian decorrela- tion timescales are used as the forcing mechanisms (shear-dominated boundary layer) for the turbulent dispersion. The model performance was established by comparing ground- level concentrations with Over-Land Alongwind Dispersion experimental results. Line source emissions was evaluated using the CALPUFF model with different forms of the initialization. A second model was also tested, normally used to study and predict the environmental impact and validate turbulent parameterizations. Is the stochastic La- grangian dispersion model LAMBDA (Ferrero and Anfossi, 1998). Also in this study the model LAMBDA and CALPUFF results emphasized the ability of the new derivation of decorrelation time scales to represent the unknown stochastic behavior.

Existe uma variedade de modelos de dispersão de poluentes, em geral, os modelos gaussianos são usados em todo o mundo por agências ambientais com intuito de regulação. O modelo CALPUFF é um deles. Neste estudo, _e avaliada a influência de escalas de tempo de descorrelação no sistema de modelagem CALPUFF, sob condições atmosféricas neutras. Para fazer isso uma nova parametrização das escalas de tempo descorrelação é proposta. Uma distribuição espectral de um perfil de velocidade euleriana e uma for- mutação da evolução das escalas temporais de descorrelação Lagrangiana são utilizadas como os mecanismos forçantes na dispersão turbulenta, numa camada limite dominada pelo cisalhamento do vento. O desempenho do modelo foi estabelecido com a comparação das concentrações superficiais do experimento Over-Land Alongwind Dispersion. Emissões de fontes em linha foram avaliadas com o modelo CALPUFF com distintas formas de inicialização. Um segundo modelo também foi testado, normalmente utilizado para estudar e prever o impacto ambiental e validar parametrizações turbulentas. É o modelo estocástico de partículas Lagrangiano LAMBDA. Também neste estudo, os resultados do modelo LAMBDA e CALPUFF enfatizam a capacidade da nova derivação de escalas de tempo em representar o comportamento estocástico desconhecido do fenômeno da dispersão de poluentes. / There exists a variety of pollution of dispersion models and in general, Gaussian models are used worldwide by environmental agencies in regulatory applications. The CALPUFF model is one of them. In this study, the in uence of decorrelation time scales in the CALPUFF modeling system under neutral conditions is evaluated. To do this a new parameterization of decorrelation time scales is proposed. A spectral distribution of an Eulerian velocity pro le and a formulation of the evolution of the Lagrangian decorrela- tion timescales are used as the forcing mechanisms (shear-dominated boundary layer) for the turbulent dispersion. The model performance was established by comparing ground- level concentrations with Over-Land Alongwind Dispersion experimental results. Line source emissions was evaluated using the CALPUFF model with different forms of the initialization. A second model was also tested, normally used to study and predict the environmental impact and validate turbulent parameterizations. Is the stochastic La- grangian dispersion model LAMBDA (Ferrero and Anfossi, 1998). Also in this study the model LAMBDA and CALPUFF results emphasized the ability of the new derivation of decorrelation time scales to represent the unknown stochastic behavior.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-05-14T20:44:44Z No. of bitstreams: 1 WALÉRIA SOUZA FIGUEIRA – DISSERTAÇÃO (PPGMET) 2015.pdf: 2735921 bytes, checksum: c2ab85caa20115480b90d1325acfad13 (MD5) / Made available in DSpace on 2018-05-14T20:44:44Z (GMT). No. of bitstreams: 1 WALÉRIA SOUZA FIGUEIRA – DISSERTAÇÃO (PPGMET) 2015.pdf: 2735921 bytes, checksum: c2ab85caa20115480b90d1325acfad13 (MD5) Previous issue date: 2015-03-05 / CNPq / Este trabalho teve como objetivo estudar o efeito da remoção de umidade da camada limite planetária por cúmulos rasos. Para tal, esse efeito foi inserido no código do modelo BRAMS. Foram realizados dois experimentos: no primeiro experimento de controle (EXP_ORI), o modelo foi inicializado em sua forma original e no segundo (EXP_AJUST), o modelo foi integrado para as mesmas condições que o EXP_ORI, porém com o devido ajuste realizado no código do BRAMS. O modelo foi integrado para um período de 774 horas a partir da 00 UTC do dia 1° de janeiro até a 00 UTC do dia 1° de fevereiro de 2011. Para facilitar a análise quanto ao impacto desse ajuste no ciclo diário médio das variáveis termodinâmicas de superfície e da precipitação convectiva, foram feitas médias em duas áreas distintas de 1°x1°, uma área sobre superfície florestada (localizada no sul do Amazonas) e outra área sobre superfície desflorestada (localizada no norte da Bolívia). De forma geral, os resultados mostraram que houve diferenças notáveis no perfil termodinâmico da troposfera inferior devido à implementação do novo ajuste. As taxas de aquecimento e umedecimento, em ambas as áreas, tiveram picos as 09 e 09:30 horas local, embora o seu efeito líquido tenha se mostrado nas horas seguintes, o principal impacto ocorreu no início da tarde. O ciclo diário dos fluxos à superfície também foram sensíveis ao ajuste realizado no modelo. Já o comportamento e a quantidade da precipitação convectiva acumulada ao longo do dia foram melhorados no EXP_AJUST, principalmente na área desflorestada. / The objective of this work was to the effects of moisture removal from the planetary boundary layer by shallow cumulus. To reach this goal, this effect was implemented into the BRAMS model code. Two experiments were performed: in the control experiment (EXP_ORI), the model was initialized in its original form and in the second one (EXP_AJUST) the model was run to the same conditions as the EXP_ORI but with due adjustment made in BRAMS code. The model was run for a period of 774 hours, from 00 UTC of 1 January to 00 UTC of 1 February 2011. To facilitate the analysis of the impact of this adjustment on the mean daily cycle of thermodynamic variables of surface and convective precipitation, averages were performed in two different areas of 1° x 1°, an area of forested area (located in the south of the Amazon) and other deforested area on surface (located in northern Bolivia). Overall, the results showed that there were important differences in the thermodynamic profile of the lower troposphere due to the implementation of new setting in the BRAMS code. Values of moistening and heating rates in both areas peaked around 09 and 09:30 local time, although their net effect were felt later, the impact occurred mainly early afternoon. The daily cycle of surface fluxes were also sensitive to the adjustment performed in the model. Also the behavior and the amount of convective precipitation accumulated during the day in EXP_AJUST were improved, especially in deforested area.

Les objectifs de la présente thèse sont l'analyse des mécanismes de couplage surface-atmosphère contrôlant la température moyenne de surface et son cycle diurne dans les régions sèches, humides et de transition.Nous montrons le rôle clé de l'inertie thermique sur la température de surface dans les régions sèches. La sensibilité à l'inertie thermique de la température de nuit est plus élevée que la sensibilité de la température de jour, impactant la température moyenne journalière. Nous montrons que cet effet est directement lié à l'instabilité de la couche limite, plus forte le jour que la nuit. Nous mettons également en lumière le double rôle du forçage solaire : Le premier est d'être la source du contraste diurne de la couche limite, à l'origine de la dissymétrie de réponse de la température à l'inertie thermique, le second est d'atténuer cet effet, puisque la forte dissymétrie du forçage solaire favorise la sensibilité de la température de jour par rapport à la nuit.Dans les régions humides, nous constatons que la sensibilité de la température de surface à l'inertie thermique est très faible. Ceci est dû aux fortes valeurs du flux latent qui contrôle la température de surface. Néanmoins, nous signalons que l'inertie thermique peut impacter le bilan d'eau à la surface, comme dans la région de la mousson indienne par exemple.Dans les régions de transition, nous montrons que la relation entre la température et l'humidité de surface est atténuée de 20 à 50 \% environ, du fait de la dépendance de l'inertie thermique à l'humidité de surface. Nous suggérons ainsi d'intégrer l'effet de l'humidité sur l'inertie thermique en plus de son effet sur l'évaporation. / The main objectives of this study are to analyze the surface-atmosphere coupling mechanisms controlling the mean temperature and its diurnal cycle in the dry, humid and transitional zones. We show that thermal inertia plays a key role on the surface temperature in dry regions. The sensitivity of surface temperature to thermal inertia is high during the night but low during the day, impacting the mean surface temperature. We demonstrate that this effect is directly related to the instability of the planetary boundary layer, which is higher during the day compared to the night.Moreover, we emphasize the dual role of the solar forcing. The first one is to be the source of the diurnal contrast of the planetary boundary layer, which is the origin of the diurnal asymmetry of the surface temperature response to thermal inertia. The second one is to attenuate this effect, since the high asymmetry of the solar forcing foster the sensitivity of the day temperature compared to the night. In humid regions, we notice that the sensitivity of the surface temperature to thermal inertia is weak. This is due to the high values of the latent heat flux which controls the surface temperature. Nevertheless, we should point out that the thermal inertia may have an impact on the water budget at the surface, as it is the case in the Indian Monsoon region. In the transitional regions, we show that the relation between surface temperature and soil moisture is attenuated by about 20 to 50 % because of the dependency of the thermal inertia to soil water content. Hence, we suggest to integrated the effect of soil moisture on the thermal inertia in addition to its effect on evaporation.

The Charles University Large-eddy Microscale Model (CLMM) and its application are presented. It is a numerical model for simulation of turbulent flow and dispersion in the planetary boundary layer. CLMM solves the incompressible Navier-Stokes equations in the Boussinesq approximation and describes turbulence using the large eddy simulation. Three applications of the model are presented. In the first case, the model is applied to the stable boundary layer over a flat terrain. The second case presents the simulations of stably stratified flows over obstacles. The last case deals with the dispersion of a hazardous material within an urban canopy. It was performed in the frame of the COST Action ES1006 and uses the Michelstadt flow and dispersion dataset for model validation.