文安地震前华北区域长波辐射场的异常特征分析

Research on anomalous characteristics of outgoing longwave-radiation (OLR) of Northern China before Wen′an M_S5.1 earthquake

利用NOAA/IR极轨卫星所获取并发布的热红外长波辐射(OLR)月平均网格数据信息(空间分辨率为2.5°×2.5°),采用涡度处理方法,在对华北地区OLR多年背景场分布特征分析的基础上,详细研究了2006年7月4日河北文安5.1级地震前华北地区OLR的短期异常演化特征。结果显示,华北地区OLR正常背景场变化较为平稳,但在文安地震之前这种平稳均一的分布格局发生了变化,主要表现为在地震发生之前2个月,在震中附近出现了OLR的显著增强异常现象。结合以往开展的大量的震例分析结果,显示出这种震前的异常演化特征具有广泛的普适性。这一认识的取得对于开展华北地区地震短临预报应用研究具有一定的现实意义。

An earthquake with Ms5.1 occurred in Wen＇an County, Hebei Province in north China, on July 4, 2006. Based on monthly average Grid data with spatial resolution of 2.5°×4 2.5°, getting from observations of NOAA/IR polar orbit satellite in recent years, this paper analyzed the anomalous characteristics and its evolvement in time series on ambient field of OLR in north China by using Eddy covariance means before the earthquake. The research result is as follows. The change of normal ambient field is stable, the OLR value is changed with a notably anomaly two months earlier before the earthquake, and the phenomena usually happened around the epicenter. Combining previous earthquake case study by using the similar method, the characteristics of OLR anomaly before earthquake takes the catholicity. The result must have great practical significance in the short-term earthquake prediction in Northern China.