Cooperative Detection And Analysis Of Multi Remote Sensing In Miquan Fire Area,Xinjiang

The underground coal fire has become a worldwide disaster.Among them,Xinjiang coal fire is a serious disaster area,which has the characteristics of large quantity,large area and fast speed of new fire area.It will bring huge environmental pollution and energy waste every year,so it is urgent to monitor and control the fire area.At present,remote sensing technology shows great potential in the recognition and monitoring of coal fires.It is the most common method to detect temperature anomalies and subsidence in the fire area by using thermal infrared technology and InSAR technology.However,the extraction of thermal anomalies and the accurate inversion of subsidence information,as well as the fusion of multi-source data for the accurate identification and dynamic monitoring of fire areas need to be further improved.In addition,the coal fires in Xinjiang are mostly caused by the failure of effective control of abandoned coal mines.The fire area and mining area are staggered,and the surface of mining area is mostly low specific heat capacity,which is easy to produce high temperature phenomenon after solar radiation.This special geographical environment will cause more subsidence and surface high temperature areas caused by non coal fires,resulting in misjudgment of fire areas.In order to realize the accurate recognition and dynamic monitoring of wide area coal fires in Xinjiang,the following research work has been carried out and some research results have been achieved:(1)The land surface temperature is retrieved by Landsat 8 data and the abnormal temperature area is extracted.After terrain correction,the universal single channel algorithm has better performance in the temperature inversion of the fire area.Aiming at the inaccuracy of the extraction of the thermal anomaly area,the time series adaptive gradient method is proposed based on the analysis of a variety of extraction methods to extract the thermal anomaly area in the study area;(2)This paper analyzes the reasons why the traditional time-series InSAR technology is not effective in fire area monitoring and the characteristics of the surface features of the fire area.It is the first time that DS-InSar technology is applied in fire area identification and monitoring.(3)Two innovative steps,strong constraint and weak constraint,are put forward to identify Xinjiang fire area.Specifically,strong constraint is to construct band-passfilter by using subsidence and NDVI information.The extracted thermal anomaly information is filtered twice respectively.After filtering,the coal fire area range and coal fire risk grade are evaluated.Weak constraint is to reduce the missed judgment of the fire area,and to deal with the weak constraint of the coal fire area determined by the strong constraint and the surrounding high coal fire risk area.The area satisfying any two information thresholds is determined as the misjudgment coal fire area.The coal fire identification scheme proposed in this paper is verified to have good accuracy.(4)Time series subsidence and temperature analysis are carried out for the identified fire area,and the relationship between temperature and subsidence is analyzed.Through the subsidence analysis,it is found that the subsidence rate of the fire area shows the phenomenon of near accelerated subsidence,and the subsidence phenomenon of the fire area is obviously slow,so it is concluded that the effect of the fire extinguishing project is better.In addition,through the analysis of time series subsidence in the study area,it is found that coal fire and coal mining lead to different laws of subsidence,which provides a new idea for fire area monitoring using subsidence information.This paper infers that the combustion state in the fire area shows a weakening trend in 2017 by using the method of thermal anomaly range change and temperature profile comparison.In the comparative analysis of the relationship between temperature and subsidence,this paper uses the two steps of temperature and subsidence profile comparison and the comparison of measured coal fire point temperature and subsidence information to analyze.Through the comparative analysis,it is found that there is a strong negative correlation between the temperature and subsidence in the fire area.There are 52 figures,11 tables and 112 references.