Analyzing the relationship between urban heat island and land use/cover changes in Beijing using remote sensing images

摘要

In this study, three scenes of Landsat TM/ETM+ images covering Beijing area were used to examine the relationship between the UHI and land use and land cover (LULC) changes, as well as between the UHI and vegetation greenness. The brightness temperatures, LULC, and NDVI were retrieved from the calibrated images. The results showed that the urban or built-up area in Beijing has increased by 4.07% from 1988 to 2005, with nearly 5.7% of vegetated land lost during the same period. The barren area was also increased in this period as large number of land was taken over for urban construction. Seasonal pattern of UHI was obvious with highest UHI intensity observed in summer and lowest in winter. Moreover, with the rapid urbanization, the extent of UHI expanded with newly hot spots emerged surrounding the central urban area. In addition, higher NDVI or vegetation coverage leads to higher land surface temperature (LST) in winter and lower LST in summer. This was due to the different thermal characteristic between vegetated area and non-vegetated area. Therefore, increasing vegetation coverage can be beneficial to the mitigation of UHI effect in urban area in hot season while to keep the land warmer in cold season.