Coal fire burning around the world is an environmental catastrophe characterized by the emission of noxious gases, particulate matter, and condensation by-products. In this study, coal fire temperature is retrieved ba...Coal fire burning around the world is an environmental catastrophe characterized by the emission of noxious gases, particulate matter, and condensation by-products. In this study, coal fire temperature is retrieved based on Landsat 5 TM images and Generalized Single-Channel Algorithm (GSCA), in Wuda coalfield, Inner Mongolia, China. Then coal fire zones are extracted by Jenks′ natural breaks and threshold methods based on temperature images. Changes of coal fire zones are analyzed from 1989 to 2008. The results are summarized as follows: 1) The coal fire temperature retrieval method based on Landsat 5 TM and the GSCA model is effective and feasible, because the temperature error is relatively small (from –2.9℃ to +2.6℃) between the measured temperature and the retrieved temperature. 2) The accuracy is relatively high to extract coal fire zones through the Jenks′ natural breaks and threshold methods, because 83.56% of surveyed area is located in the coal fire zones extracted in 2005. 3) The coal fire area increased 9.81 × 10 5 m 2 from 1989 to 2005, and the annual growth is about 6.1 × 10 4 m 2 , with an annual increasing rate of 2.48%. The area of coal fire decreased by 8.1 × 10 5 m 2 from 2005 to 2008.展开更多
Satellite images are used extensively in studying the urban heat island(UHI)phenomenon.We evaluated the suitability of thermal infrared(TIR)data from the HJ-1B satellite for detecting UHI using a case study in Beijing...Satellite images are used extensively in studying the urban heat island(UHI)phenomenon.We evaluated the suitability of thermal infrared(TIR)data from the HJ-1B satellite for detecting UHI using a case study in Beijing.Two modified algorithms for retrieving the land surface temperature(LST)from HJ-1B data were tested.The results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST output.The spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS data.Of the two algorithms,the mono-window algorithm performed better but further tests are necessary.With more frequent coverage than TM and higher spatial resolution than MODIS,the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in China and neighboring countries.展开更多
基金Under the auspices of International Program for Cooperation in Science and Technology (No. 2007DFA20640)National High Technology Research and Development Program of China (No. 2009AA12Z146, 2009AA12Z124)National Natural Science Foundation of China (No. 40701172)
摘要Coal fire burning around the world is an environmental catastrophe characterized by the emission of noxious gases, particulate matter, and condensation by-products. In this study, coal fire temperature is retrieved based on Landsat 5 TM images and Generalized Single-Channel Algorithm (GSCA), in Wuda coalfield, Inner Mongolia, China. Then coal fire zones are extracted by Jenks′ natural breaks and threshold methods based on temperature images. Changes of coal fire zones are analyzed from 1989 to 2008. The results are summarized as follows: 1) The coal fire temperature retrieval method based on Landsat 5 TM and the GSCA model is effective and feasible, because the temperature error is relatively small (from –2.9℃ to +2.6℃) between the measured temperature and the retrieved temperature. 2) The accuracy is relatively high to extract coal fire zones through the Jenks′ natural breaks and threshold methods, because 83.56% of surveyed area is located in the coal fire zones extracted in 2005. 3) The coal fire area increased 9.81 × 10 5 m 2 from 1989 to 2005, and the annual growth is about 6.1 × 10 4 m 2 , with an annual increasing rate of 2.48%. The area of coal fire decreased by 8.1 × 10 5 m 2 from 2005 to 2008.
基金supported by Startup Fund for Talented Scholars,Beijing Forestry University(Grant No.0001115000)State Key Laboratory of Remote Sensing Science Open Fund(Grant No.2009KFJJ021)+1 种基金sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal UniversityNational Key Technology Research and Development Program of China(Grant No.2009AA12200101)
摘要Satellite images are used extensively in studying the urban heat island(UHI)phenomenon.We evaluated the suitability of thermal infrared(TIR)data from the HJ-1B satellite for detecting UHI using a case study in Beijing.Two modified algorithms for retrieving the land surface temperature(LST)from HJ-1B data were tested.The results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST output.The spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS data.Of the two algorithms,the mono-window algorithm performed better but further tests are necessary.With more frequent coverage than TM and higher spatial resolution than MODIS,the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in China and neighboring countries.