The comparison of vegetation index and surface temperature composites for urban heat-island analysis

Relationships between urban-rural differences in minimum (in situ) air temperature (T min), normalized difference vegetation index (NDVI), and apparent surface radiant temperature (T sfc) were examined for 28 cities in the U.S.A. from 28 June through to 8 August 1991. Composites based on NDVI and thermal-IR data, and consistency in urban-rural differences in NDVI and T sfc were examined. The urban-rural differences in T sfc, whether based on an NDVI composite or a composite based on thermal-IR data, were not as consistent as the urban-rural differences in NDVI. The composite process utilized, based on NDVI or thermal-IR data, did not appear to contribute to the generally low correlation between urban-rural differences in T min and T sfc observed in previous studies.