| In this study, MODIS's (Moderate Resolution Imaging Spectroradiometer-Earth Observing System) land surface temperature (LST) products of eight-day composite images at 10:30 am, 1:30 pm, 10:30 pm, and 1:30 am are used to study urban heat island (UHI) phenomenon over four major Texas cities (El Paso, Dallas-Ft. Worth, Houston, and San Antonio) from the Summer of 2000 to the Fall of 2008. The eight-day LST products are used to generate spatial maps characterizing the temperature distribution and UHI spatial extent for each city.The results indicate that (1) UHI can be observed in night time images in Dallas-Ft. Worth, Houston, and San Antonio all year long the intensities of UHI are larger in night times of spring and summer seasons than those of fall and winter seasons (2) UHI consistently appears in night time images in El Paso-Juarez and the intensities of UHI are similar in all seasons (3) the day time images contain large amounts of cloud contamination in Dallas-Ft. Worth, Houston, and San Antonio which make the use of day time images to map UHIs in those cities difficult and (4) from the temperature climatology maps (seasonal mean and yearly mean) of the 8 years, it is found that Aqua/MODIS LST products in the night time (1:30 am) is the best for mapping UHI for all four cities and that the spatial extent and pattern of the UHI differs from the expected HI usually centered in downtown of a city. |
