Remote Sensing The Spatial Distribution Of The Heat Island Effect In Shijiazhuang City

Urban heat islands (UHI) means the air temperature in a developed city tend to be obviously higher than the suburban area as if there was a higher temperature island standing up surrounded by the low temperature region. The reason for UHI formation in the urban area comes from the artificial land covers, air pollution and artificial hot emission.Satellite images from Landsat system for three dates in 1987, 1993, and 2000 were used to analyze the spatial distribution characteristics over Shijiazhuang city. The image data were mainly processed by software of Erdas Imagining in this study. Firstly, the image data were converted into .img files that could be directly read in by Erdas. Then the .img files were regular processing steps and were modified into good quality for using in subsequent model computation in UHI analysis.Then the ground temperature was computed using a single-channel model put forward by jiménez-Mu?oz and Sobrino in 2003. The maps of ground temperature distribution in Shijiazhuang city were generated. In the meantime the ground albedo (ε) model and the inversion ground temperature model were set up.The city area was classified in to 5 grade by the knowledge-based Erdas classifier. They were hight temperature area, higher area, medium temperature area, lower temperature area, low temperature area. The classified temperature images were generated for the three dates. Matched points in both the generated NDVI map and ground temperture map were selected to do the correlation analysis between NDVI and ground temperature. The both were negative correlated.Landscape analyzing method from ecology was used to analyze the spatial thermo-dynamics landscape in shijiahzuang.The sixth, using the economic index of the city in 1987~2000 to analyze the possible reason to produce the UHI in shijiazhuang. The method to alleviate the UHI effect were put forward the based on the analysis.According to the research result in this thesis, Because of the different seasons and years, the distribution of city's heat island are also differences . However, their distribution of heat island also has the same following characteristics: Heat island was more distribution centres; Cotton textile industry center are always the heat island city centre; The lower the temperature in urban areas are parks which covered by more vegetation or the areas which cover by waters.Low-temperature Centre only appear in the suburbs.The ground temperature was generally lower in the high NDVI regions.The thermal landscape is similar with the UHI distribution characteristics in Shijiazhuang city.