Heat Island Effect and Urban Storm Events of San Antonio Downtown Area by MODIS/AQUA Temperature Sensor

摘要

Urban environmental conditions are strongly dependent on the land use and land cover properties and radiant thermal field of the land cover elements in the urban mosaic. Observations of urban reflectance and surface temperature provide valuable constraints on the physical properties that might be the determinants of urban storm formation. It is assume that consistencies in the covariation of land surface temperature with convective rainfall distribution can be identified to represent characteristics of the surface energy flux associated with different meteorological conditions. We retrieved the temperature from MODIS/Aqua (PM satellite) MYD11A1 temperature product (8-day composite and 1 km spatial resolution). Time period used is from June 1 to September 30 of year 2002 to 2008. MODIS reflectivity data and rainfall data corresponding to those dates were also used to verify the hypothesis. However, partial correlations may be seen in the time series analysis accounting for some convective storm events. Yet the San Antonio urban heat island (UHI) over the sea-breeze convergence zone along the coastal bend might affect the storm events too. Obviously, the other of the storm events were triggered by frontal cyclone at the continental scale that might not be directly related to the local UHI effects at all. Nevertheless, spatial analyses in relation to the NEXRAD images confirm spatial correlation between precipitation and UHI within at least 2 storm episodes.