Abstract: Heat island effect is an important factor for evaluating urban environment and climate quality. Based on RS technology, we used three remote sensing images of the main urban area of Fuyang City in 2007, 2013, and 2018 to analyze the spatiotemporal variations of land surface temperature and heat field grade using the methods of land surface temperature inversion, underlying surface parameter extraction, and correlation analysis. We further examined the evolution trend of urban thermal environment and the correlation between surface temperature and surface parameters. The results showed that there was an obvious heat island effect in the main urban area of Fuyang City, with the trend being first dispersed and then concentrated with time. Compared with the case during 2013-2018, the proportion of areas with reduced and unchanged thermal field grade increased in 2007-2013, while the proportion of areas with enhanced thermal field grade decreased. Spatially, heat island effect increased gradually from north to south. There was a negative relationship between land surface temperature and Normalized Difference Vegetation Index (NDVI) and TC-Wetness (Wet), but a positive relationship between land surface temperature and Normalized Difference Build-up Index (NDBI) and bare soil index (BSI). The contribution of different underlying surface indices to land surface temperature was different, with Wet index having the strongest effect on reducing temperature. Every 0.1 increase of Wet index would reduce temperature by 5.383 ℃ in 2007, 2.645 ℃ in 2013, and 3.289 ℃ in 2018, respectively.

Key words: RS, heat island effect, temperature inversion, land surface parameter, main urban area of Fuyang City.