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


Remote sensing and the spatial analysis technology have been recognized and used as powerful and effective tools to monitor urban land usage and surface changes. Satellite remote sensing collects multi-spectrum, multiresolution, multi-period data and provides valuable information in understanding and monitoring the process of urban land cover change, and in constructing urban land cover databases.

The purpose of the study is to present a method of using remote sensing and spatial analysis technology in environmental topics and for this purpose, we assessed the pattern of the sudden increase in the urban area of Shanghai, China and analyzed its impact on the surface temperature.

2. Materials & Methods

Figure 1. The region covered in this study: Shanghai, China and its neighborhoods.


Our targets of study, Shanghai of China and its surburbs are located on the center of the area between of the western part of the Pacific Ocean and the Chinese coastal line running from south to north. As shown in
, its latitude is between 30°59'N and 31°24'N and its longitude is between 121°17'E and 121°44'E. The city of Shanghai is situated on the banks of the Yangtze River Delta, where Huangpu River meets Yangtze River and contains the wide area around the city center and the island of Chungming near the mouth of the Yangtze River. Them main river in Shanghai is the Suzhou river. The climate is warm and the annual average temperature is 15°~16°, and the average rain fall is 1,100 ~1,200 ·. The population of Shanghai in 2001 is 16 million and 740 thousand. The outskirts of Shanghai belongs to northern subtropic region and has fertile soil with agricultural area of 333,000ha. An area near Shanghai is on a delta with fertile soil and has many small and large tributaries running north-south and east-west, beside Suzhou river[2,3].

The sudden economic growth in Shanghai brought about changes in land usages and the land surface patterns. This study adopts the method of analyzing the pattern of surface changes and impact on surface temperature due to that 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[4]. Using the satellite data, the region was divided into urban areas (including asphalt and concrete road), agricultural regions, hydro regions (rivers, lakes and ocean), and unclassified regions. ISODATA unsupervised classification was used to classify the land cover based on the satellite images. For quantitative analysis of the land cover classification results, we made the error matrix and for quantitative analysis of surface change we made land cover change matrix.

To analyze the change in the surface temperature due to the change of the surface, we used Landsat infra-red heat data photographed in August 11, 1989 and July 3, 2001. 1989 data were acquired by Landsat 5 TM and 2001 data were acquired by Landsat ETM+. In this study, ATCOR2 atmosphere calibration algorithm was used to calculate surface temperatures from satellite data from Landsat 5 TM. In ATCOR2 atmosphere calibration algorithm[5,6], we assume that surface radiation rate e for infra-red spectrum (10.5 - 12.5 ·) in Landsat 5 TM is 0.98.

3. Results and Discussion
Land surface map was constructed based on the classification of land surface of Shanghai, China and its neighborhood using Landsat satellite image. The land surface was classified into urban, agricultural, hydro and unclassified regions. The overall classification accuracy for the years of 1979, 1989, 2001 were 93.01%, 90.44% and 88.23%, respectively. The Kappa coefficients, which measure the reliability of the result, were analyzed to be 0.84, 0.80 and 0.78, respectively

The land surface map with this level of classification accuracy can be used to detect the change of land surface. To analyze the land surface change from 1979 to 2001, land cover change matrix was constructed using the land surface map constructed above. We analyzed the land surface change using the superimposed land surface maps of 1979 and 1989 to find out that there was change of 3.34% in overall area. That corresponds to 27,196ha. The urban area had the greatest increase of 40.06% from 1979 to 1989. On the other hand, the agricultural region decreased by 0.41%. The land surface change from 1989 to 2001 was analyzed to be decreased by 17.07% in overall area. Also in this case, the urban area had the greatest increase of 146.50%. On the other hand the agricultural region decreased by 11.65%. The land surface change from 1979 to 2001 was analyzed to be 20.40% in overall area. That corresponds to 166,354ha. The rate of change in urban regions was 245.25%. Hence the urban region area increased more than two folds during the period. On the other hand the agricultural region decreased by 12.01% in 2001 compared to 1979.


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