China Aero Geophysical Survey and Remote Sensing Center for Land and Resources
Email: [email protected]
Subsurface coal fires in the north of China are a serious disaster.They consum the precise natural energy resources,lead to environmental pollution,land subsidence and degradation of land resource.The regular monitoring of these fires is crucial to know the area,depth and movement of fires in order to take fire mitigation action. Underground coal fires can be detected by some indicators such as surface thermal anomalies.
A study is presented for extracting the thermal anomalies from TIR bands of ASTER datawhereas the thermal data record the surface radiance within 8.125-11.65ƒÊm spectral range provide information about radiant temperatures which are determined by kinetic temperature and the emissivity of surface materials. A simple quantitative way to extract thermal anomaly is to select the background value plus a constant as the division threshold.The background value is assumed as the average pixel value in a subarea in this study.The variation of the surface temperature and the heterogeneity can be expressed as the standard deviation of the thermal data.The standard deviation or several times of the standard deviation can be taken as the constants. The surface thermal anomalies are derived from ASTER thermal infrared data at study area.The resultant indicated that an integrated anomalous product shows the area affected by underground coal fires