Urban Heat Island Assessment with Temperature Maps Using High Resolution Datasets Measured at Street Level

摘要

The impact of heat on human health has been subject of many studies showing that during extreme weather events, mortality increases in urban areas. Cities, such as New York, form heat islands all year round. This is primarily due to land surface modifications, radiative trapping in urban canyons and lack of cooling through evapotranspiration caused by displaced trees and vegetation. Urban Heat Island (UHI) refers to an increase in air and surface temperature in urban centers compared to surrounding suburban and rural areas. Large scale environmental forcing can cause subdivisions of UHI throughout a city. The combined effects leads to the formation of hot pockets within the cities at micro-scale and it is difficult to pick out these physically defined regions using satellite remote sensing which has traditionally focused on regional and global scale. The highest spatial resolution available on an environmental satellite is 30 meters in visible and 60-100 meters in thermal infrared bands. The main challenge in using satellite data to study UHI in urban environment is the complexity of the system and lack of information on near surface air temperature in fine scale. This work consists of high resolution data sets measured at the street level in Manhattan, New York to produce temperature maps showing smallest hotspots which could not be identified using high resolution satellite. Data from two consecutive years of field campaigns at street level, plus various significant parameters that control temperature in an urban setting such as building height, building density, vegetation, water, elevation and albedo were used to create temperature maps using statistical model to locate hot spots in the system.