A cidade de São Paulo passou por cinco grandes reurbanizações desde 1825 até os dias atuais que intensificaram o uso do solo em detrimento do clima urbano. A partir de 1960 a região central entra em um processo de decadência e, em 2002, é lançado o Programa de Reabilitação da Área Central de São Paulo (Procentro) para reverter esta situação por meio de intervenções distribuídas pelos distritos da Sé e da República que, levando em consideração as questões ambientais, reduzirão a intensidade da ilha de calor paulistana. / The city of São Paulo passed through five major urbanizations since 1825 until today that intensified land use over urban climate. Since 1960 the central region goes into a process of decay, and in 2002 is being launched Rehabilitation Program of the Central Area of São Paulo (Procentro) to reverse this situation through assistance distributed by the Districts of the República and Sé and that taking into consideration environmental issues, reduce the intensity of the heat island of São Paulo.

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This study examines the relationship between land use and temperature change in Dallas County, TX. The purpose of this research is to analyze the relationship between temperature and land use and to identify the primary factors contributing to the formation of urban heat islands based on different categories of land use. Specifically, this research analyzes the elements that contribute to the urban heat island effect in Dallas County using temperature data provided by remote sensing imagery and parcel-based land use data using Geographic Information System (GIS) technique and a correlation analysis method, which was employed to analyze the relationship between temperature and land use. The results of this study showed that every land use category has different temperature averages and those patterns were observed similarly in both 2000 and 2005. Parking, airport, commercial, industrial, and residential areas have relatively high temperatures. In contrast, water, undeveloped area and parks showed relatively low temperatures. Another major finding was ratio of land use composition affected the temperature of census tracts. Correlation analyses of land use and temperature in 2000 and 2005 indicate that various types of land use categories have significant relationships with temperature. Among them commercial, industrial, residential, parking, and infrastructure, are positively associated with temperature, while undeveloped, parks, water, and dedicated areas are negatively associated with temperature. Areas with a high ratio of commercial use showed the highest and undeveloped areas showed the lowest relationship. Furthermore, through the analysis of the relationship between land use and temperature change for five years (2000-2005), this study finds that temperature change depends on the ratio of each land use category change. The results of this study can help local planning and policy decisions which are related to urban land use planning concerning temperature change such as zoning, environmental regulations and open space preservation.

Population growth and urban sprawl have contributed to the formation of significant urban heat island phenomena in Houston, Texas, the fourth largest city in the United States. The population growth in Houston was 25.8% between 1990 and 2000 nearly double the national average. The demand for information concerning the effects of urban and suburban development is growing. Houston is currently the only major US city lacking any kind of comprehensive city zoning ordinances. The Normalized Difference Vegetation Index (NDVI) has been used as a surrogate variable to estimate land surface temperatures at higher spatial resolutions, given the fact that a high-resolution remotely sensed NDVI can be created almost effortlessly and remotely sensed thermal data at higher resolutions is much more difficult to obtain. This has allowed researchers to study urban heat island dynamics at a micro-scale. However, this study suggests that a vegetation index alone might not be the best surrogate variable for providing information regarding the independent effects and level of contribution that tree canopy, grass, and low-lying plants have on surface temperatures in residential neighborhoods. This research combines LIDAR (Light Detection and Ranging) feature height data and high-resolution infrared aerial photos to measure the characteristics of the micro-structure of residential areas (residentialstructure), derives various descriptive vegetation measurement statistics, and correlates the spatial distribution of surface temperature to the type and amount of vegetation cover in residential areas. Regression analysis is used to quantify the independent influence that different residential-structures have on surface temperature. In regard to implementing changes at a neighborhood level, the descriptive statistics derived for residential-structure at a micro-scale may provide useful information to decision-makers and may reveal a guide for future developers concerned with mitigating the negative effects of urban heat island phenomena.

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 118-122). Also available in print.

Urbanization is known to cause significant changes to the properties of local climate. The Urban Heat Island (UHI) has been shown to add an additional burden to the impacts of global warming, impose risks on human health, and indirectly worsen air and water qualities. Studies have shown that urban areas, compared to rural areas with less artificial buildup, experience higher local temperatures as a result of UHI. Hong Kong is one of the most densely populated cities in the world with a high proportion of her population residing in urbanized areas. The hot and humid sub-tropical monsoon climate echoed with densely packed high-rise buildings and a high traffic volume can give rise to severe local thermal discomfort. To fully characterize the spatial and temporal aspects of UHI within Hong Kong’s urban areas, this study deployed 58 small, durable and low-cost logging sensors to measure road-side temperature/humidity measurements at 15-minute time intervals. The data collection was conducted over 17 consecutive days in the summer (September) and repeated in the winter (January) at two typical urban locations: Mong Kok and Causeway Bay. By employing the geographic information system (GIS) and global positioning system (GPS) software, the sampled data were mapped against urban structures and land uses to investigate the urban microclimate and the role of various environmental factors at the sampling locations. Official meteorological conditions for the duration of study were obtained from the Hong Kong Observatory to validate the sensors and to explore microclimate variations by comparing official (urban and rural monitoring stations) and sampled readings. Temporal variations of urban temperature were examined for daily, weekly and seasonal differences. Spatial and temporal variations were examined using spatial interpolation and hotspot analysis, as well as in a 3D representation with building models for better visualization. This empirical study establishes the methodological feasibility and reliability of employing small and inexpensive logging sensors for widespread deployment in places with hot and humid subtropical climates. The validation outcome indicated that road-side and control measurements were strongly correlated (r>0.81) and their average difference was well within the ±1 C measurement accuracy claimed by the manufacturer. Significant microclimate variations within the urban area were observed and characterized by five environmental settings: major road, secondary road, public activity area, green park and tunnel. Temporal variations of UHI were evident for all time scales, with the daily highest UHI at around midnight and daily lowest at around noon to early afternoon which also exhibited urban cool island (UCI) effects. A UHI Threat Rating was introduced for better understanding of microclimate variations and easier appreciation of hotspots. A 3D-GIS building model enhanced spatial-temporal analysis of UHI over a near “real” and 3D environment. The study and its methodology set a sound foundation and provide essential framework for future studies on microclimate variation and UHI effects. Given that modern cities have mixed land uses and are increasingly vertical, this micro-level study helps address local issues on human comfort and brings in the broader picture of environmental health in an urban setting. / published_or_final_version / Geography / Doctoral / Doctor of Philosophy

The urban heat island effect is considered one of the main causes of global warming and is contributing to increasing temperatures in the urban United States. This phenomenon enhances the intensity of summer heat waves and the risk to public health due to increased exposure to extreme thermal conditions. Characteristics of spatial development patterns can significantly affect urban temperature because they are related to the arrangement of development and land surface materials, which are crucial elements needed to determine land surface temperature. While previous studies revealed that the effect of the urban heat island varies depending on different land use types and surface characteristics, few have considered the overall development patterns of urban form. I address this under-studied aspect of heat hazards by analyzing the relationship between spatial development pattern and urban heat island effect across a sample of 353 metropolitan regions of the U.S. Specifically, I employ a series of landscape metrics to measure urban development patterns using a national land cover dataset from the U.S. Geological Survey. Linear regression models are used to statistically isolate the effect of different spatial development patterns on increasing the urban heat island effect while controlling for multiple contextual variables including built-environment, environmental, and demographic characteristics. The result of this study showed that the daytime mean surface urban heat island effect (4.04˚F) is higher than that of nighttime (2.41˚F). Ecological context (i.e. Ecoregions) has proved to be a statistically significant modulator that helps to explain the spatial distribution of the urban heat island effect. Regarding the main research question of this study, the results indicate that specific categories of urban development pattern including density, continuity, and clustering are statistically associated with increasing the urban heat island effect. This initial evidence suggests that the overall development patterns are an important issue to consider when mitigating the adverse impacts related to the urban heat island effect. In addition, when contextual heat contributors are held constant, the intensity of the urban heat island effect can differ depending on the configuration of development in urban areas. This study can be used as a starting point for a comprehensive approach to both spatial land development and hazard-resistant planning by providing alternative ways of measuring and modeling spatial development patterns.

Bibliography: p. 133-144. / x, 170 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis investigates the impact on residential energy use for climate control or urban design variables, such as building density, spacing and orientation. Energy use for heating/cooling is predicted in a range of urban configurations that are compatible with the following objectives: wind shelter and solar access in winter and urban ventilation and shading in summer. / Thesis (Ph.D.)--University of Adelaide, Dept. of Architecture, 1997?

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

The winter urban heat island (UHI) has been suggested to reduce snowfall downwind of city centers due to localized energy and moisture flux variations, but previous research lacks spatial detail since it is primarily based on sparse surface observations. This project utilizes high-resolution radar data for twelve snow-only events, occurring from 1995-2008 and passing over the Minneapolis – St. Paul (MSP) urban area, to quantify the change in radar reflectivity values downwind of the city. Results show that five of the twelve snowfall events evaluated for the MSP urban area did not significantly decrease in summed decibel (dBZ) values downwind of the city center, and four of these events occurred on a day with a zero to positive urban-rural temperature gradient. Analysis of related atmospheric variables on these days suggest that atmospheric instability and convergence may play a critical role in urban snowfall modification.