Analysis On Urban Heat Island Effect And The Dynamical Change Of Urban Surface Biophysical Descirptors

The dynamics of urban biophysical descriptors, represented mainly by impervious surface,vegetation and open water, can affect the quality of urban thermal environment (UTE). The studyfocuses on the quantitative relationship between impervious surface and land surface temperature(LST) because the impervious surface has for many years been recognized as an indicator of theintensity of the UTE and, with the advent of urban sprawl, become a key issue in urban habitathealth. The city's biophysical properties of Jiaxing, Shaoxing and Huzhou, e. g., impervioussurface, vegetation and water, along with LST in1994and2009were retrieved from the LandsatTM images of the corresponding years. We want to reveal the dynamic character of land use andLST of these three cities, which could provided reference for city planning policies anddistribution of the Hangzhou Economic Circle.(1) On present situation of the study area in2010, the various components of the proportionof land cover type of Jiaxing was nearly consistent with Shaoxing, the ratio of impervious surfaceto vegetation and water was3:6:1, which was2:6:2in Huzhou. Huzhou had the best landscapepattern of all. The area ratio of urban heat island (UHI) in Jiaxing was very low (about6.15%),which had little difference in Shaoxing and Huzhou, the ratio was12.08%and12.26%respectively.(2) On present situation of the urban area in2010, the urban area of Jiaxing was72.36km~2,which was the biggest of all. Huzhou had the best landscape pattern of all. The area ratio of urbanheat island (UHI) in Jiaxing was very low (about29.53%), which was46.81%and78.31%respectively in Shaoxing and Huzhou,(3) On the variance in study area during16years, the impervious surface area of Jiaxing grewfastest,2.26times than before, which had little difference in Shaoxing and Huzhou. Thevegetation area of Shaoxing increased in Shaoxing, which was decreased in Jiaxing and Huzhou.The landscape pattern of study area of all the three city was getting worse, which was worst inJiaxing. The area ratio of UHI in Jiaxing increased4.6%,3.97times than before.(4) On the variance in urban area during16years, the urban area of Jiaxing grew fastest, which was5.58times than before. The landscape pattern of urban area of all the three city wasgetting better, which was best in Jiaxing. The area ratio of UHI in Jiaxing decreased26.83%,0.52times than before.