Simple Normalization of Multi-Temporal Thermal IR Data and Applied Research, on the Monitoring of Typical Coal Fires in Northern China

摘要

China is one of the countries with vast coal resources in the world. However, Many coal mines in China are seriously endangered by coal fires. Investigations showed that there were 104 coal fires in Northern China. About 100-200 million tons of coal is being lost because of coal fires each year, accounting for one-fifth of national annual coal production. More seriously, coal fire also endangered human beings and property security, induced disastrous ecological damage and environmental pollution. Though the problem of coal fires is long standing and not only limited to China, little has been done around the world for regular monitoring of these fires based on remotely sensed data. Some researchers used daytime thermal infrared (TIR) images from Landsat TM or ETM+ band 6 to monitor coal fires. Nevertheless, the combined impacts such as solar radiation, topographic shadowing, cover of vegetation, emissivity and different thermal inertia of ground objects result in the different background temperatures in different coal fires, and also lead to the thermal anomalies extracted out from multi-temporal thermal IR images lack of comparability. The intensity and extending range of thermal anomalies change frequently. It is a big puzzle for us to process continuous monitoring for coal fires. As a result, this research took different surface environmental parameters into account, and extracted out thermal anomalies based on the normalization of multi-temporal thermal IR images.