Abstract:

In this paper,we used the monowindow algorithm to retrieve land surface temperature in Wuhan using HJ1B CCD/IRS as the main data source,and preliminarily validated the result using the MODIS temperature products. Next,thermal field variance composite index was obtained from the land surface temperature and the spatial distribution feature of Wuhan was analyzed,and the quantitative description on the urban heat island effect was given. Last,the impact of land covers types on heat island was analyzed. The conclusions are as follows:(1) The urban heat island was mostly concentrated in the urban areas and showed irregular characteristics of staggered distribution on the whole and agglomeration of some areas. There were some small islands with higher temperature in the big heat islands.(2) The average of land surface temperature on behalf of summer high temperature days from 2009 to 2012 in Wuhan city was 30611 K,land surface temperature in most urban area was 309-317 K.(3) Thermal field variation composite index in the main urban area exceeded 0015 and manifested a very strong effect of heat island. Area percentage of six intensities of heat island effect declined from 3671% to 352% in turn,but the corresponding average land surface temperature increased from 29898 K to 3152 K. Heat island intensities and the mean value of the land surface temperature went up simultaneously. (4) Heat island intensity level differed by the type of surface area. In terms of land cover composition,the proportion of water decreased,the proportion of vegetation increased and then decreased,while the proportion of impervious surface had gradually increased.The results can provide a scientific basis for monitoring and ecological evaluation of the urban thermal environment