Analysis On Urban Heat Island Effect And The Dynamical Change Of Urban Surface Biophysical Descriptors In Southwest Zhejiang

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 study focuses 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 the intensity of the UTE and, with the advent of urban sprawl, become a key issue in urban habitat health. The city’s biophysical properties of Jinhua, Quzhou and Lishui, e. g., impervious surface, vegetation and water, along with LST in1994and2009were retrieved from the Landsat TM images of the corresponding years. We want to reveal the dynamic character of land use and LST of these three cities, which could provided reference for city planning policies and distribution of the Southwest area of Zhejiang Provence.(1) On present situation of the study area in2010, Lishui had the best landscape pattern of all, Jinhua was worst. The urban heat island proportion index (URI) in Lishui was very low (about0.25), which had little difference in Jinhua and Quzhou, the ratio was0.29and0.33respectively.(2) On present situation of the urban area in2010, the urban area of Jinhua was104.24km2, which was the biggest of all. The urban area of Lishui was only41.54km, which was the smallest of all, but which had the best landscape pattern. The area ratio of urban heat island (UHI) in Quzhou was very low (about48.04%), which was67.54%and88.76%respectively in Jinhua and Lishui.(3) Due to the actively facilitate afforestation work, the forest canopy density of Southwest area of Zhejiang Provence increased significantly. On the variance in study area during16years, the vegetation area of three cities was basic constant. The area of water increased in Lishui, which decreased in Jinhua and Quzhou. The landscape pattern of study area of Jinhua and Quzhou was getting worse, which was getting better in Lishui. The area ratio of UHI in Jinhua increased5.68%,2.38times than before, and which increased2.23%in Quzhou,2.06times than before.(4) On the variance in urban area during16years, the urban area of Lishui grew fastest,4.87times than before. The landscape pattern of urban area of Lishui and Quzhou was getting better, which was best in Lishui. The area ratio of UHI in Jinhua decreased21.52%,1.47times than before, which was1.52and1.94times than before respectively in Jinhua and Lishui.