Characteristics of urban heat island distribution in Guangxi Beibu Gulf Economic Zone based on MOD11A2

Abstract

The diurnal variation and inter-annual variation of urban heat island in Beibu Gulf Economic Zone were quantitatively analyzed, based on 2005-2014 MOD11A2 land surface temperature dataset, by the method of land surface temperature departure. Furthermore, the relationship between vegetation NDVI and urban heat island intensity were studied. Results showed: (1) Spatial distribution and extent of urban heat island in Beibu Gulf Economic Zone had a certain difference between daytime and nighttime in summer, the temperature departure decrease with distance from the city center increasing, and the decreasing trend of daytime was significant compared with nighttime. The temperature difference was about 4 to °C between the city and suburb in the daytime, and was about 2-6°C at night (2) The inter-annual variation intensity of urban heat island was not obvious in summer daytime during 2005-2014, while the difference of spatial distribution was significant. The urban heat island intensity increased in Nanning city during 2005-2011, and slowed in 2014. The heat island variation intensity was not obvious in Beihai city before 2011, but increased significantly in 2014. (3) The correlation coefficient between NDVI and land surface temperature in summer is -0.29, which showed high vegetation coverage plays an important role in reducing the urban heat island.