【摘要】 为获取与构造活动有关的卫星热红外异常信息,提出了一种基于参考基准场的震前热红外遥感定量分析模型与异常识别方法.对遥感图像进行辐射定标、几何校正、云检测等处理后,根据研究区内不同时相遥感图像像元的亮温值与空间平均值之差及其时间域平均值与标准差,计算热红外异常图像像元的异常指数,提出了异常识别方法;进而计算当前热红外异常图像各像元亮温值与序列遥感图像的多年平均亮温之差,建立异常定量分析模型.利用多年热红外遥感资料建立目标区的参考基准场,并采用此异常识别方法与定量分析模型,分析了1998年张北Ms6.2级地震前热红外异常的演化特征.结果表明:1月5日沿张家口-渤海断裂出现异常,1月8日异常面积达到最大,为64.7万km2,最高增温幅度达到9 K,11日异常消失.更多还原

【Abstract】 To extract the thermal infrared(TIR) anomaly information related to the tectonic activities from remote sensing data,a new pre-earthquake TIR anomaly recognition method and quantitative analysis model based on reference field are presented.Firstly,the radiometric calibration,geometric calibration and cloud detection should be done for all images.Later,according to the difference between the brightness temperature value and the spatial average value of each pixel at different time,and to the time average values and the standard deviation values of each pixel,the TIR anomaly indexes of remote sensing image pixels in the investigated area are calculated,and an anomaly identification method is presented.Furthermore,the difference between the brightness temperature value of each pixel of present image and the corresponding years-average brightness temperature value from series images were calculated,and a quantitative analysis model is established to extract the TIR anomaly information.With the setting up of the reference field of the target area from remote sensing images for years,and by using of the anomaly identification method and the quantitative analyzing model,the evolution features of TIR anomaly variation before Zhangbei earthquake,Ms6.2,1998,are analyzed.The results show that 1) there was distinguishable TIR anomaly appeared along the Zhangjiakou-Bohai Sea fault zone on January 5,1998,2) the area of the TIR anomaly is 647 000 km2 and reached the maximum on January 8,1998,and the amplitude of the TIR anomaly is 9 K.3) the TIR anomaly disappeared on January 11,1998.更多还原