地面能见度观测在卫星遥感IDDI指数中的融合应用

为了弥补卫星遥感沙尘监测云区之下的缺失信息,同时改进卫星遥感沙尘产品的精度,进行地面水平能见度资料与风云二号气象卫星红外差值沙尘指数(InfraRed Difference Dust Index,IDDI)的融合处理。首先采用2006~2010年3~5月沙尘多发期4:00~6:00的IDDI以及6:00的水平能见度建立两者的相关关系,结果表明:在西北地区,卫星沙尘指数IDDI与站点水平能见度之间呈较好的线性相关关系,而且3~5月的不同月份呈现不同的相关系数。然后利用所建立的相关关系将水平能见度资料转换为IDDI;最后对其进行融合处理,对存在IDDI观测值的像素利用周围站点的水平能见度资料采用反距离加权法进行修正,对不存在IDDI观测值的情况利用周围站点的水平能见度资料采用反距离加权法进行插值,得到沙尘观测结果。将该方法分别应用于2007年5月10日以及2008年4月20日发生在西北地区的沙尘过程中,得到较好的融合结果。同时显示出该方法更适用于沙尘过程强度较大,地面观测站点主要集中在卫星观测边缘附近的特征。

Duststorm Detection by Merging Meteorological Visibility with Remote Sensing IDDI

To make up for the missing information over cloudy area of satellite remote sensing dust product,while improving its precision,visibility data monitoring by routine meteorological stations is fused with Infrared Difference Dust Index (IDDI) of FY-2 meteorological satellite.At first,the linear correlation between visibility and IDDI is built by data from each month of March,April and May from 2006 to 2010.Then visibility is transferred to IDDI with the developed correlation.And finally the Inverse Distance Weighted (IDW) method is applied to make them fusion.To pixels with IDDI values,visibility is used to improve its precision while to pixels without IDDI values,visibility is integrated to complement the missing information.This method is applied to dust process which happened in west-northem of China on the May 10,2007 and April 20,2008 and well demonstrates its accuracy.The comparison also showed that the process is more suitable for greater intensity dust,especially in the case that surface meteorological stations are located near the edge of satellite observations.