This study presents the results of a modeling effort to explore the role that sustainable roofing technologies play in impacting the rooftop energy balance, and the resultant net sensible heat flux into the urban atmosphere with a focus on the summertime urban heat island. The model has been validated using data from a field experiment. Roofing technologies explored include control dark membrane roof, a highly reflective (cool) roof, a vegetated green roof, and photovoltaic panels elevated above various base roofs. Energy balance models were developed, validated with experimental measurements, and then used to estimate sensible fluxes in cities located in six climate zones across the US. To evaluate the impact on urban air temperatures, a mesoscale meteorological model was used. Sensible flux profiles calculated using a surface energy balance were used as inputs to the mesoscale model. Results for a 2-day period in Portland, OR are analyzed. Average findings indicate that the black roof and black roof with PV have the highest peak daily sensible flux to the environment, ranging from 331 to 405 W/m2. The addition of PV panels to a black roof had a negligible effect on the peak flux, but decreased the total flux by an average of 11%. Replacing a black roof with a white or green roof resulted in a substantial decrease in the total sensible flux. Results indicate that if a black membrane roof is replaced by a PV covered white or a PV covered green roof the corresponding reduction in total sensible flux is on the order of 50%. Mesoscale modeling results indicate peak daytime temperature reduction of approximately 1°C for both white and green roofs. However, there is a nighttime penalty on the order of 0.75°C for the green roof case, which has been attributed to the additional thermal storage of a green roof. Findings also reveal that the addition of PV panels to a roof has a nighttime cooling effect. This is most pronounced on a white roof, with magnitudes of 1°C. The methodology developed for this analysis provides a foundation for evaluating the relative impacts of roof design choices on the urban climate and should prove useful in guiding urban heat island mitigation efforts.

Our climate and our cities are changing. Though their changes are not completely dependent upon one another, there is still a coupling effect between them. This study assesses the role of urban form as it pertains to elements of climate change. It is comprised of two essays intended for publication. The first of these essays addresses the feedbacks between urban form, energy consumption, and rising global temperatures. The second essay looks at one particular factor of urban form--tree type--as it pertains to air pollution and urban heat island mitigation. Both papers use the analytical approaches necessary to answer the questions they pose, not ubiquitous over-generalizing modeling software or methods found often in the literature. As seen in the analyses, this practice--known as geocomputation--allows for a deeper and more accurate description of complex spatial relationships.

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

No description available.

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-08-13T19:37:46Z No. of bitstreams: 1 NIKOLAI DA SILVA ESPINOZA – DISSERTAÇÃO (PPGMET) 2017.pdf: 3187688 bytes, checksum: 3f6f29d810cd5a2c18108d0d7b68009a (MD5) / Made available in DSpace on 2018-08-13T19:37:46Z (GMT). No. of bitstreams: 1 NIKOLAI DA SILVA ESPINOZA – DISSERTAÇÃO (PPGMET) 2017.pdf: 3187688 bytes, checksum: 3f6f29d810cd5a2c18108d0d7b68009a (MD5) Previous issue date: 2017-02-22 / Capes / A ilha de calor urbana (ICU) é um fenômeno importante devido aos seus impactos diretos e indiretos sobre as populações humanas em ambientes urbanos. Esse fenômeno tem sido estudado amplamente usando tanto medições diretas a partir de sensores de temperatura do ar instalados em estações meteorológicas ou a bordo de veículos, como dados de temperatura da superfície medidos por sensoriamento remoto. Neste trabalho foi avaliada a variabilidade temporal e espacial da ICU na cidade de Manaus utilizando dados de precipitação, temperatura e umidade do ar em cinco estações meteorológicas distribuídas na área urbana e uma na área rural durante o período de julho de 2013 a julho de 2014. Adicionalmente, foram obtidas imagens do sensor OLI/TIRS a bordo do satélite Landsat 8 em quatro dias da estação menos chuvosa para estimar a temperatura da superfície e parâmetros de superfície, tais como o NDVI na área que estão inseridas as estações meteorológicas. Os resultados indicaram que a ICU atmosférica ocorre preferencialmente no período noturno, sendo mais intensa e condicionalmente desconfortável durante a estação seca da região. A partir das imagens de satélite, pode-se observar uma relação inversamente proporcional entre a temperatura da superfície e o NDVI, onde a maior variação de temperatura da superfície está localizada em áreas com pouca ou nenhuma vegetação. / The urban heat island (ICU) is an important phenomenon due to its direct and indirect impacts on human populations in urban environments. This phenomenon has been studied extensively using both direct measurements from air temperature sensors installed in fixed weather stations or mobile surveys using automobiles and remotely measured surface temperature data. This work evaluated the temporal and spatial variability of ICU in the city of Manaus using precipitation, temperature and air humidity data in five meteorological stations distributed in the urban area and one in the rural area during the period from July 2013 to July 2014. In addition, images of the Landsat 8 OLI / TIRS satellite were obtained in four days of the less rainy season to estimate the surface temperature in the area comprising the meteorological stations. The results indicated that atmospheric ICU occurs preferentially at night, being more intense and conditionally uncomfortable during the dry season of the region. From the satellite images, an inversely proportional relationship between the surface temperature and the NDVI can be observed, where the highest surface temperature variation is located in areas with little or no vegetation.

The aim of this study was to detect surface temperature changes in the České Budějovice during last 30 years. The aim was also to asses the influence of vegetation on the surface temperature. The study is based on the thermal data acquired by the Landsat TM 4 and 5 and the study site was in the České Budějovice and surroundings.

Les villes jouent un rôle majeur dans le changement climatique à l'échelle globale au travers des émissions de gaz à effet de serre qu'elles génèrent. Mais elles peuvent aussi influencer le climat aux échelles locale et régionale car elles traduisent une altération des modes d'occupation des sols qui modifie les échanges thermodynamiques entre la surface et l'atmosphère. Les études d'impacts en milieu urbain se concentrent principalement sur les effets du changement climatique sur le climat local des villes (et plus largement, sur un ensemble de dimensions environnementales) selon des approches ne tenant pas compte des rétroactions potentielles. Les hautes résolutions horizontales atteintes aujourd'hui par les modèles de climat régionaux rendent légitime et pertinent d'inclure une modélisation explicite des villes dans ces modèles pour traiter les interactions ville/climat. Le couplage du modèle de climat régional ALADIN à 12 km de résolution avec la plateforme de modélisation des surfaces continentales SURFEX intégrant le modèle de canopée urbaine TEB permet d'évaluer l'impact de l'urbanisation à l'échelle régionale. L'analyse de sensibilité comparant différentes approches de modélisation des zones urbaines montre que les villes modifient significativement la température de l'air proche de la surface. Les plus grandes agglomérations françaises induisent un réchauffement le jour et la nuit, qui s'étend au-delà des limites de la ville et affecte l'environnement à l'échelle régionale. La comparaison des simulations à de longues séries d'observation sur la région parisienne révèle que la modélisation explicite des processus urbains avec TEB reproduit mieux la dynamique journalière de l'îlot de chaleur urbain et son intensité en phase nocturne que l'approche conventionnelle des modèles de climat décrivant les villes comme de la roche. L'activation de TEB dans le modèle ALADIN permet donc de mieux représenter l'impact des villes sur les climat régional. Néanmoins, les études d'impacts du changement climatique sur les villes nécessitent une descente d'échelle complémentaire. Une simulation a été réalisée avec le modèle AROME couplé à SURFEX(TEB) à 2.5 km puis 1.3 km de résolution sur l'agglomération toulousaine pour la période couvrant la campagne expérimentale CAPITOUL (2004-2005). Les bénéfices de la paramétrisation urbaine sont confirmés à ces échelles. Les tests de sensibilité réalisés sur les différentes versions de TEB mettent en lumière la forte sensibilité des performances du modèle à la qualité des simulations atmosphériques AROME et à la précision des données de surface. Pour ces résolutions et avec les bases de données actuelles, les paramétrisations les plus sophistiquées de TEB (échanges turbulents dans la canopée urbaine, énergétique du bâtiment, végétation explicite) n'apportent pas d'amélioration par rapport à la version historique voire dégradent les résultats. Il reste donc des voies d'amélioration à explorer pour la configuration AROME-Climat avec SURFEX(TEB), aussi bien sur la physique et la dynamique du modèle atmosphérique que sur la qualité des bases de données. En parallèle, différentes méthodes de descente d'échelle à très haute résolution sur les villes sont envisagées pour raffiner encore les études d'impacts. / Greenhouse gas emissions generated by cities play a major role in climate change at a global scale. But cities can also influence the climate at the local and regional scales as they reflect an alteration of land-use that modifies the thermodynamic exchanges between the surface and the atmosphere. Impact studies in urban areas focus mainly on the effects of climate change on the local climate of cities (and more broadly on a range of environmental dimensions) using approaches that do not account for the feedback with the atmosphere. The high horizontal resolutions reached by regional climate models make it relevant to include explicit modeling of cities to address city/climate interactions. Coupling the ALADIN regional climate model ALADIN (12 km horizontal resolution) with the SURFEX modeling platform integrating the model of urban canopy TEB allows to evaluate the impact of the urbanization at the regional scale. Sensitivity analyses that compare different urban canopy modeling shows that cities significantly modify the near-surface air temperature. The largest French cities induce a warming day and night, which extends beyond the limits of the city and affects the environment on a regional scale. Comparison of the simulations with long-term time series of observations on the Paris region reveals that the explicit modeling of urban processes with TEB improve the daily dynamics of the urban heat island and its nocturnal intensity compare to the conventional approach of climate models that describes cities as rock. The activation of TEB in the ALADIN model thus makes it possible to represent the impact of cities on the regional climate. Nevertheless, impact studies of climate change on cities require a further downscalling. A simulation was carried out with the AROME model coupled with SURFEX (TEB) at 2.5 km and 1.3 km resolution on the agglomeration of Toulouse for the period covering the CAPITOUL experimental campaign (2004-2005). The benefits of urban parametrization are confirmed. The tests carried out on the different versions of TEB highlight the high sensitivity of the model's performance to the quality of the AROME atmospheric simulations and the accuracy of the surface description. For these resolutions and with the current databases, the most detail parametrization of TEB (turbulent exchanges in the urban canopy, building energy budget, explicit vegetation) do not seem relevant compared to the historical version. New develompents could thus benefits to the AROME-Climat configuration with SURFEX (TEB). In particular, The physics and dynamics of the atmospheric model as well as the accuracy of the databases could be improved. At the same time, various downscalling methods at very high resolution on the cities are envisaged to enhance the spatial resolution needed by the impact studies.

abstract: Rapid urban expansion and the associated landscape modifications have led to significant changes of surface processes in built environments. These changes further interact with the overlying atmospheric boundary layer and strongly modulate urban microclimate. To capture the impacts of urban land surface processes on urban boundary layer dynamics, a coupled urban land-atmospheric modeling framework has been developed. The urban land surface is parameterized by an advanced single-layer urban canopy model (SLUCM) with realistic representations of urban green infrastructures such as lawn, tree, and green roof, etc. The urban atmospheric boundary layer is simulated by a single column model (SCM) with both convective and stable schemes. This coupled SLUCM-SCM framework can simulate the time evolution and vertical profile of different meteorological variables such as virtual potential temperature, specific humidity and carbon dioxide concentration. The coupled framework has been calibrated and validated in the metropolitan Phoenix area, Arizona. To quantify the model sensitivity, an advanced stochastic approach based on Markov-Chain Monte Carlo procedure has been applied. It is found that the development of urban boundary layer is highly sensitive to surface characteristics of built terrains, including urban land use, geometry, roughness of momentum, and vegetation fraction. In particular, different types of urban vegetation (mesic/xeric) affect the boundary layer dynamics through different mechanisms. Furthermore, this framework can be implanted into large-scale models such as Weather Research and Forecasting model to assess the impact of urbanization on regional climate. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016

Submitted by Luciana Sebin (lusebin@ufscar.br) on 2016-09-14T12:46:38Z No. of bitstreams: 1 TeseCMNO.pdf: 7498079 bytes, checksum: f4a2b7e655a7e6fb0d19d9ed7a9144b1 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-15T13:59:13Z (GMT) No. of bitstreams: 1 TeseCMNO.pdf: 7498079 bytes, checksum: f4a2b7e655a7e6fb0d19d9ed7a9144b1 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-15T13:59:18Z (GMT) No. of bitstreams: 1 TeseCMNO.pdf: 7498079 bytes, checksum: f4a2b7e655a7e6fb0d19d9ed7a9144b1 (MD5) / Made available in DSpace on 2016-09-15T13:59:24Z (GMT). No. of bitstreams: 1 TeseCMNO.pdf: 7498079 bytes, checksum: f4a2b7e655a7e6fb0d19d9ed7a9144b1 (MD5) Previous issue date: 2016-01-19 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nocturnal heat island formation is a prominent phenomenon in research of urban planning and thermal comfort. This phenomenon is the result of the influence of urbanization characteristics, which alter the energy balance of the cities, and is characterized by an increase in air temperature, from the periphery to the center of cities. The heat island has as a major cause, the urban geometry. In this context, the model proposed by Oke, in 1981, became a reference in the area because of its importance in analytical studies of relation between urban geometry and the formation of heat islands. This research aims to determine the role of urban geometry in the formation of nocturnal heat islands, from the adaptation of a simplified model for a computational simulation tool GIS (Geographic Information System). The methodological procedures have steps: study of theoretical and numerical base, developing a calculation algorithm and its incorporation into the GIS platform, data monitoring for calibration (validation) and simulation. The measured data for the tool validation demonstrated an increasing trend of heat island with increasing H/W ratio (height/width) canyon, but there are different behavior for different ranges of roughness length (Z0). The developed tool, THIS (Tool for Heat Island Simulation), was used in simulation of different scenarios, which showed that urban canyons of greater roughness result in heat island values twice lower compared to the canyons of lower roughness, for the same H/W ratio. The development of THIS tool expands the possibilities of simulations to forecast heat islands to different climatic conditions and suggests further discussion on the influence of different urban geometry settings in the formation of heat island. / A formação de ilha de calor noturna é um fenômeno de destaque em pesquisas de planejamento urbano e conforto térmico. Esse fenômeno é resultado da influência das características da urbanização, que alteram o balanço energético das cidades, e caracteriza-se pelo aumento da temperatura do ar, da periferia para o centro das cidades. A ilha de calor tem como uma das principais causas, a geometria urbana. Nesse contexto, o modelo proposto por Oke, em 1981, se tornou referência na área por sua importância em estudos de análise de relação entre a geometria urbana e a formação de ilhas de calor. Esta pesquisa tem como objetivo verificar o papel da geometria urbana na formação de ilhas de calor noturna, a partir da adaptação de um modelo simplificado para uma ferramenta de simulação computacional SIG (Sistema de Informação Geográfica). Os procedimentos metodológicos contam com as etapas de: estudo da base teórico-numérica, desenvolvimento de um algoritmo de cálculo e sua incorporação à plataforma SIG, monitoramento de dados para calibração (validação) e simulação. Os dados medidos para a validação da ferramenta demonstraram uma tendência crescente da ilha de calor com o aumento da relação H/W (altura/largura) do cânion, mas há comportamentos distintos para diferentes faixas de comprimento de rugosidade (Z0). A ferramenta desenvolvida, THIS (Tool for Heat Island Simulation), foi utilizada em simulação de diferentes cenários, que demonstrou que cânions urbanos de maior rugosidade resultam em valores de ilha de calor duas vezes menor em relação aos cânions de menor rugosidade, para um mesmo valor de relação H/W. O desenvolvimento da ferramenta THIS amplia as possibilidades de simulações para previsão de ilhas de calor para diferentes condições climáticas e sugere uma discussão mais aprofundada sobre a influência de diferentes configurações de geometria urbana na formação de ilhas de calor.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-05-15T18:12:29Z No. of bitstreams: 1 EWERTON VÔLNEY DA SILVA COSTA – DISSERTAÇÃO (PPGMET) 2015.pdf: 5145716 bytes, checksum: 472ebd5a74a9a155a582c84c559c918d (MD5) / Made available in DSpace on 2018-05-15T18:12:29Z (GMT). No. of bitstreams: 1 EWERTON VÔLNEY DA SILVA COSTA – DISSERTAÇÃO (PPGMET) 2015.pdf: 5145716 bytes, checksum: 472ebd5a74a9a155a582c84c559c918d (MD5) Previous issue date: 2015-08-27 / Capes / O crescimento desenfreado das cidades é um problema decorrente do aumento da população, causando inúmeras complicações para a sociedade e meio ambiente, como por exemplo, poluição, assoreamento de rios, desmatamento, alterações no clima local ou regional. O aumento da temperatura está diretamente ligado ao crescimento urbano, sendo influenciado pelo alto índice de construções, poluição, redução da vegetação e impermeabilização do solo, ocasionando problemas para a saúde dos habitantes e um desconforto térmico, gerando as chamadas ilhas de calor urbano (ICU). O estudo tem como objetivo identificar áreas propícias para a formação das ICU, caracterizar as mudanças do uso e ocupação do solo sobre a temperatura, estimar o saldo de radiação e os índices de vegetação (NDVI), água (NDWI) e área construída (NDBI) no período entre 1985 e 2007 em Londrina/PR. Foram gerados diagramas de dispersão com o intuito de analisar as relações entre os índices e a temperatura. Durante esse período, a vegetação e as áreas de solo exposto perderam espaço para a malha urbana, que apresentou um crescimento superior a 17%. A temperatura mínima encontrada na zona urbana com o passar dos anos fica cada vez mais elevada, em 1985 apresentou 22,4°C, já em 2007 apresentou 26,3°C, um aumento de aproximadamente 4°C. A temperatura na malha urbana também se apresentou mais elevada em comparação com as outras classes, chegando a marcar mais de 8°C em comparação com a vegetação densa. As temperaturas mais altas se apresentam nas regiões de solo exposto, estradas e alta densidade de edificações e as menores temperaturas foram identificadas nos corpos hídricos. A relação entre temperatura e os índices, indicou que quanto maior a temperatura, menor os valores de NDVI e NDWI. Já o NDBI, apresentou valores maiores à medida que a temperatura aumenta. / The rampant growth of cities is a problem due to increased population, causing numerous complications for society and the environment, such as pollution, silting of rivers, deforestation, changes in local or regional climate. The temperature rise is directly linked to urban growth, being influenced by the high number of buildings, pollution, reduction of vegetation and soil sealing, causing problems for the health of inhabitants and thermal discomfort, generating the so-called urban heat islands (ICU ). The study aims to identify areas suitable for the formation of the ICU, to characterize the changes of land use and occupation over temperature, estimate the net radiation and the vegetation index (NDVI), water (NDWI) and building area (NDBI ) between 1985 and 2007 in Londrina / PR. Scatter plots were generated in order to analyze the relationship between the indexes and the temperature. During this period, vegetation and bare soil areas lost space to the urban fabric, which showed a growth of 17%. The minimum temperature found in the urban area over the years becomes increasingly higher in 1985 showed 22.4 ° C in 2007 showed 26.3 ° C, an increase of about 4 ° C. The temperature in the urban also showed the highest in comparison with the other classes, reaching scores more than 8 ° C as compared with dense vegetation. The higher temperatures present in the soil exposed areas, roads and buildings high density and lower temperatures have been identified in water bodies. The relationship between temperature and indices indicated that the higher the temperature, the lower the NDVI values and NDWI. Since the NDBI, had larger values as the temperature increases.