Analysis of Land Surface Changes and Environmental Impact Using Landsat Thermal Infrared Data

摘要

In this paper, we use multi-temporal remote sensing data to analyze the pattern of surface change of the city of Shanghai and its neighborhoods brought on by the sudden development of the city and analyze how the surface change affects the change in surface temperature. To detect the surface change, the study used the satellite data of Landsat 3 MSS in 1979, Landsat 5 TM in 1989, Landsat ETM+ in 2001. To analyze the surface change of 22 years, the study used each of the satellite data to make the land surface maps, superimposed them together and analyzed the quantitative data for the amount of the surface change. We applied ISODATA unsupervised classification algorithm to classify them and made error matrix to verify the classification accuracy. The classification accuracy for the land cover maps was analyzed to be 93.01%, 90.44%, 88.23%, respectively. We analyzed the amount of the surface between 1979 and 2001 to find the change of 20.40%. That corresponds to the area of about 166,354ha. The rate of change in the urban area was 245.25%. Hence the size of the urban area increased more than two-folds during the period. To analyze the change in the surface temperature due to the change of the surface, we used Landsat thermal infrared data photographed in August, 1989 and July, 2001 to make the surface temperature distribution map. To analyze the impact of the surface change on the surface temperature, we superimposed the land cover map and the surface temperature distribution map to find out the change of the surface temperature according to land cover type. The average surface area in 1989 and 2001 were 23.55°C and 28.78°C hence increased by about 5°C in 12 years. The difference in the temperature of the urban area and the agricultural area was found to be 2.01°C in August, 1989 and 2.38°C in July, 2001, hence the difference increased by 0.37°C. This result can be seen to verify the increase in the surface temperature due to urbanization. The increase in temperature due to global warming can be one factor to this, but the change in the material such as concrete, asphalt, and steel that cover roads, buildings and industrial complex built due to the sudden increase of the urban area seem to have a bigger impacts.