Monitoring Spatio-Temporal Changes of Heat Island Effect in Beijing Based on HJ-1B

Abstract

The change of land surface temperature(LST)can reveal the heat environment of city,which leads to urban heat island(UHI).As a metropolis,Beijing has a serious urban heat island effect,so,analyzing and studying spatial and temporal changes of Beijing's urban heat island has a great significance.In this paper,we referenced image-based method to retrieve the land surface temperature using Environment Satellite image(HJ-1B) CCD/IRS as the main data source from 2008 to 2011,made preliminary validation on retrieval result using MODIS temperature products,then analyzed the annual and inter annual changes of urban heat island effect in Beijing.Further,we used thermal field variability index to make quantitative analyze of UHI.Finally,we analyzed the relationship among NDVI,NDBI and land use types.The results show that:(1) between 2008 and 2011,there is a significant heat island effect in Beijing.The heat island expanded from 2008 to 2010 but eased in 2011,the UHI were 5.2℃,5.2℃,9.2℃ and 8.2℃,respectively;(2) There is a significant heat island effect in four seasons of Beijing in 2010,the heat island in summer is the strongest,followed by spring and autumn,winter is the weakest,and the UHI were 8.2℃,9.4℃,9.2℃ and 4.3℃,respectively;(3) The quantitative distribution of UHI in Beijing from 2008 to 2011 showed that the UHI is mainly in urban,the heat island effect in the Southern of Fangshan District and Daxing District reduced year by year,the heat island effect of Changping District in 2011 is higher than in the previous three years,and vegetation and water formed urban cool island;(4) LST and NDVI are negatively correlated.LST and NDBI are positively correlated obviously,NDVI and NDBI have a significant impact on urban heat island,and urban heat island has a clear correction with land use types.So,increasing the city green area and water area can effectively slow down the heat island effect.