The Study On Heat Island Effect In Ningbo、Wenzhou And Taizhou Based On Remote Sensing Monitoring

In this study, we analyzed the background information of the three coastal cities, Ningbo, Wenzhou, Taizhou; and analyzed the land cover and land surface temperature changes in the years of1993-2009, which were got from the vegetation, impervious surface area, water through Landsat5TM satellite images. Together with the urban expansion, economic and social development, the relationship between urban development and urban heat island effect was analyzed, and several effective measures to alleviate the urban heat island effect were proposed.During this16rapid expansion years, Ningbo City, which’s main urban area increased from8.79km2to143.65km2, is about increased114.86km2, that is about five times as large as before. Wenzhou in which is increased from16.92km2to87.49km2which is5.17times large as before. Taizhou in which is increased to11.16km2in2009, that is an increase of83.52km2which is7.5times larger than before. The above-mentioned expansion of the city leaded an increasing of the impervious area, a decreasing of the plaque fragmentation, and a larger average patch size.In Ningbo, proportion of the heat island plaque and URI index both increases, and the heat island effect enhanced; proportion of the heat island plaque both changed a little in Wenzhou and. Taizhou, while the and URI index were both remains the same. Those three cities’ heat island effects are all weakened and the plaque area ratios together with the URI are all fell. This study suggests that the main reason for alleviate of the heat island effect of built-up areas is the built urban vegetation area and its proportion for the build area is larger.The patch spatial distribution of the heat island is closely related with urban economic and social development. The construction and development of Ningbo is based on a type of ring-shaped outward expansion, and the economic structure is based on the heavy industry which is highly consumed of energy which is relatively concentrated. The heat island patches is relatively concentrated in the main city while supplemented by the scattered distribution according to the map; Due to its different natural and economic conditions from Ningbo’s, Wenzhou and Taizhou where the small towns developed rapidly. Their economic patterns are low-power light industry which has the local characteristics, and performed scattered on the graph in1993while concentrated in2009. For alleviate the heat island effect, we can take several effective mitigation measures from the scale of urban planning, architectural design and so on. First, improve the urban green coverage. Second, preserve the city’s water area. Third, control the size of the urban land use reasonably, and build urban open space.