基于卫星热红外辐射信息的新疆强震震例分析

利用NOAA-14极轨气象卫星红外波段的探测数据,对遥感数据进行多种处理,采用影像目视解释和提取地表辐射亮温值的方法,对新疆的三次强震进行分析,结果发现在地震前都出现了热红外异常,这为地震监测提供了一个重要信息。

Features of thermal infrared radiation of three strong earthquake cases in Xinjiang

In this paper,the infrared radiation information of stratum before,during and after 3 strong earthquakes(Ms > 6.0) in Xinjiang is collected from NOAA14 polar-orbiting meteorological satellite.These infrared data are transferred into images according to the principles of infrared radiation information.The integrated images are generated from channel 4,2,1 or 3 images.This paper reports the features of the temporal and spatial changes of thermal infrared radiation and bright temperature.Firstly,there is a corresponding relationship between abnormal peak temperatures and the initial times of the earthquakes.Significant temperature increase occurs at about half a month prior to the earthquake,and reaches peak in one week.Meanwhile,there are abnormal low temperatures before earthquake and rapid temperature drop after earthquake.Secondly,the surface temperature increased in a large area,including both epicenter and near epicenter area.A large amount of studies report that although the underlying mechanism of abnormal profiles of thermal infrared information detected by meteorological satellite remains unknown,but their changes just before the earthquake are consistent with the abnormal temperature increases in both the surface of the earth and the near aerosphere.Since the infrared bright temperature in a certain area of earth surface is relatively stable,it may change with the occurrence of earthquakes and correlate with the changes of infrared radiation information before,during and after the earthquake.Although imaging identification of infrared anomaly is simple and practicable,the application of this method is influenced by cloud conditions.If the cloud is relatively thick,almost all of the signals detected by satellite sensor are from the top of the cloud rather than from the earth surface because the signals from the earth surface are impeded by the cloud.On the contrary,signals detected are mixed ones when the cloud is thin.Therefore,in the paper,the impacts of cloud and bad weathers are excluded in order to improve the reliability of the identification of the abnormal infrared radiation information.