EOS—MODIS卫星资料在北疆大雾监测中的应用分析

Analyze on Monitoring Heavy Fog in Northern Xinjiang with MODIS Data

根据雾与云、积雪、裸地等地表物在可见光、长波红外和中红外波段的反射及辐射特性差异,利用MODIS卫星多通道多光谱探测数据,采用最佳波段组合法和量化判识指标法,对2006年3月8日到10日北疆大雾天气进行判识检验试验和动态监测分析。结果:发现较利于雾与背景(地物、云、雪)分离的最佳波段是可见光B0.65μm和近红外B0.85μm、短红外B1.64μm、中红外B3.7μm、热红外B11μm,综合判识就可以将云、雾、雪、裸地有效的区分;雾在夜间的有效温度在中红外波段比热红外波段低,可采用中红外和热红外波段的组合方法,根据两通道的亮温差进行雾的监测。

According to the differences of the reflection and radiation characteristics of fog, cloud, snow cover, bare land etc. in VIS, LWIR and mid-IR, with the use of MODIS detected data of multichannel spectral, and adopted the methods of optimal band combination and quantitative identification indicators, this paper carry through the examination of identification test and the analysis of dynamic monitoring for the heavy fog happened during Mar. 8-10, 2006 in Northern Xinjiang. The results indicate that the best band of conducive to the separation between fog and background （surface objects, clouds and snow） are VIS B0.65μm , near-IR B0.85μm, short-IR B 1.64μm, mid-IR B3.7μm, and thermal-IR B11μm, it may distinguish effectively for clouds, fog, snow and bare land with synthetical identification; the effective temperature of fog occurred night in mid-IR is lower than that in thermal-IR, so it can adopt the combination method with mid-IR and thermal- IR, and put up the fog monitoring according as the brightness temperature difference of two channels above