Research On Variation Of Urban Heat Island In Beijing Based On FY-3 Meteorological Satellite

In recent years, under the background of global warming and the high-speed urbanization, the urban heat environment is considered as one of the important factors that dominate the city ecological environment. Fog and haze weather has started from 2012 and lasted in following two years, therefore, study on the urban heat island attracted more and more attention of governments and scholars. Urban heat island plays important role in urban climate system, combining with urban climate system and research of ecological environment of hotspot problem. It is very necessary and meaningful to study the variation of Urban Heat Island between 2011 and 2013 in Beijing by applying FY-3 meteorological domestic satellite.Temporal and spatial variation of Urban heat island in Beijing between 2011 and 2013 was analyzed by using FY-3 meteorological satellite Visible And Infrared Radiometer sensor data,A modified Becker’ s split window approach for retrieving land surface temperature from the AVHRR and VIRR data and monitoring approach for urban heat island intensity to analysis variation of Urban heat island time and space in 2011-2013, also land surface temperature data of FY-3 is tested by Landsat-TM and EOS/MODIS Urban heat island product, finally using correlational analysis method to research Urban heat island factors. The main concludes are:(1) Variation area of Urban heat island (cold island) of Beij ing from 2011 to 2013 was that the cold island area increased 1477.31km2 and heat island area decreased 568.41km2 between 2011 and 2012; cold island area increased 1545.39km2 and heat island area decreased 547.61km2 between 2012 and 2013. Strong heat island area is increased 160.78km2 from 2011 to 2012 and decreased 154.16 km2 from 2012 to 2013. Urban heat island proportion index is 0.2、0.18、0.15 in sequence in 2011-2013. Which can be know from the urban heat island intensity and Urban heat island proportion index was that the Urban cold island area had increased and Urban heat island had decreased in general.(2) Beijing urban heat island changes obviously with seasons, the spring and the autumn heat island are not obvious, the summer is heat island and the winter is cold island. The characteristic of urban heat island characteristic of Beijing in four seasons can effectively provide advices about relieving urban heat island to the related decision-making departments.(3) City six districts of Beijing as a basic reference region, In spatial direction, strong heat island area is increased at northwest、west、 southwest in 2011 to 2012 year, decreasing at northwest west、southwest in 2012 to 2013 year. In general, the heat island (cold island) area expansion or decrease is not obviously in the direction of the north、 northeast、southeast and east.The strong cold island area in JunDushan south of Yanshan mountains and Xishan area of Taihangshan mountains has a trend of increase.(4) There are four factors in urban heat island that are land use type、 elevation、fractional vegetation cover (FVC)、 impervous surface proportion (ISP), land use types include building、forest、farmland、 grassland、water body and desert, building is the biggest factor of urban heat island; the relieving urban heat island factors are forest、farmland and grassland. The order of correlation coefficients from high to low between land use type at elevation and land surface temperature were forest、farmland、grassland、building、water body and desert. The correlation coefficient with FVC and land surface temperature was -0.716, between ISP and land surface temperature was 0.871. ISP can express urban heat island more accurate than FVC.