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Detection of Land Surface Changes and Environmental Impact Brought on by Urban Development Using Remote Sensing Data

To analyze the change in surface temperatures due to the change of the surface in Shanghai, we used Landsat infra-red heat data photographed in August 11, 1989 and July 3, 2001. The infrared image used in this study came from Landsat 5 TM and ETM+ and each has different sensors and used different temperature transformation equations. We analyzed the relation between DN values and temperatures of Landsat 5 TM and ETM+ infrared sensors to calibrate the temperature value discrepancies due to the difference of the satellite sensors used. The equation between DN values and temperatures of Landsat 5 TM data obtained in August, 1989 and Landsat ETM+ data obtained in July 2001 are as follows.

Temperature(· )· TM = 0.4407 × DNTM - 35.621
Temperature(· )· ETM = 0.4817 × DNETM - 41.121

We obtained the following equation after normalizing two equations.

Temperature(·)·TM_ETM = 0.4687 × DNTM_ETM - 39.401

We constructed the land surface temperature distribution map of August, 1989 and July, 2001 using the temperature transformation equation obtained above. 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 land surface temperature of urban, agricultural, and hydro region in 1989 were 29.38· ·, 23.37 ·· and 21.92··, respectively. They were 31.80··, 29.42·· and 25.14··, respectively in 2001. The average surface area in 1989 and 2001 were 23.55·· and 28.78·· hence increased by about 5··. The difference in the temperature of the urban area and the agricultural area was found to be 2.01·· in August, 1989 and 2.38·· in July, 2001, hence the difference increased by 0.37··. This result can be seen to verify the increase in the surface temperature due to urbanization. The monthly average temperatures data of Shanghai in July and August in 2003 were 27.8·· and 27.7··, respectively and didn't have a big difference. But the surface temperatures calculated from the satellite data photographed in August, 1989 and July, 2001 had a big difference. 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 urba n area seem to have a bigger impacts

Figure 2. Land cover map extracted from Landsat satellite data using ISODATA classification method

Table 1. Error matrix of land cover map, 1979

Table 2. Error matrix of land cover map, 1989

Table 3. Error matrix of land cover map, 2001

Table 4. Land cover change matrix, 1979-1989 (pixel)

Table 5. Land cover change matrix, 1989-2001 (pixel)

Table 6. Land cover change matrix 1979-2001 (pixel)

Table 7. Average surface temperature(·)_· by land cover type

Figure 3. Land surface temperature distribution in Shanghai, China and its neighborhoods based on Landsat 5 TM and Landsat ETM+ infrared image.

4. Conclusion
This study uses Multitemporal remote sensing data to analyze the pattern of surface change of the City of Shanghai and its suburbs 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. As the result of the analysis, we found out that the land surface change between 1979 and 1989 was 3.34%, about 27,196ha and the size of the urban area increased by 40.06%. The land surface change between 1989 and 2001 was 17.07%, about 139,176ha and the size of the urban area increased by 146.50%. 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 draw the surface temperature distribution map. We found out that the average surface temperature in 1989 and 2001 were 23.55·· and 28.78·· hence increased by about 5·· in 12 years. The difference in the temperature of the urban area and the agricultural area was found to be 2.01·· in August, 1989 and 2.38·· in July, 2001, hence the difference increased by 0.37··. This result can be seen to verify the increase in the surface temperature due to urbanization. The monthly average temperatures data of Shanghai in July and August in 2003 were 27.8·· and 27.7··, respectively and didn't have a big difference. But the surface temperatures calculated from the satellite data photographed in August, 1989 and July, 2001 had a big difference.

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.

5. References

B. L. Markham, J. C. Seiferth, J. Smid, and J. L. Barker, "Lifetime responsivity
Department of Geography, Zhongshan University, 1988, The Land and Water Resources in the Zhujiang Delta (Guangzhou: Zhongshan University Press).
Ditu Chubanshe, 1977, Provincial Atlas of the People's Republic of China (Beijing: People's Press).
P. M. Teillet, J. L. Barker, B. L. Markham, R. R. Irish, G. Fedosejevs, and J. C. Storey, "Radiometric crosscalibration of the Landsat-7 ETM+ and Landsat-5 TM sensors based on tandem data sets," Remote Sens. Environ., vol. 78, no. 1-2, pp. 39-54, 2001.
Roth,M., Oke, T. R., and Emery, W. J., 1989, Satellite derived urban heat islands from three coastal cities and the utilisation of such data in urban climatology. International Journal of Remote Sensing, 10, 1699- 1720.
Gallo, K. P., McNab, A. L., Karl, T. R., Brown, J. F., Hood, J. J., and Tarpley, J. D.,1993b, The use of a vegetation index for assessment of the urban heat island eVect. International Journal of Remote Sensing, 14, 2223-2230

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