干旱半干旱地区降雨对遥感地质信息提取影响研究

Influence of rainfall on remote sensing geological information extraction in arid and semi-arid area

以河北省围场地区的SPOT-6和OLI、ETM+作为数据源,依据该区80余天的气象条件,分别利用降雨前3景、降雨后3景遥感数据提取了蚀变遥感信息、岩石类型、环形构造、线性构造等遥感地质信息,并实测雨前雨后不同岩石类型的波谱。认为降雨后获取的遥感数据源能够有效反映研究区遥感地质信息。工作区线性纹理发育,降水能提高地物含水量,影像对比度提高,使得线性构造、环形构造及绿泥石化蚀变带在雨后遥感影像中识别程度较其在雨前遥感影像中识别程度有所提高。野外检查发现,利用雨后遥感数据提取的铁染蚀变遥感信息优于利用雨前遥感数据所提取的铁染蚀变信息,并且利用雨后遥感数据提取铁染蚀变遥感异常的损失率远低于利用雨前遥感数据提取的铁染蚀变遥感异常的损失率,而利用雨前、雨后遥感数据所提取羟基蚀变遥感异常信息基本一致。

According to 80 days'climatic situation of Weichang area in Hebei province data of Spot-6 and OLI,ETM+from 3 scences before and after rainfall are collected to extract geological information of alteration,rock types,ring structure and linear structure and spectrum of rocks are measured before and after rainfall respectively.Data after rainfall can effectively reflect the remote sensing geological information.In the 3 scenes are developed linear structure.Rainfall bring water content higher in the linear and ring structure and chloritization zones than in their surroundings thus they become contrasty and more recognizable on satellite images than on those before rainfall.Field check shows that iron stain information extraction from the after rainfall images is generally better than that from the before rainfall.The extraction of Hydroxyl anomaly is basically the same.