有云大气对AMSR-E传感器各通道微波信号影响的分析

Effects of cloudy atmosphere on microwave signals in channels of AMSR-E

被动微波遥感具有较强的穿透云、雾、雨、雪获取地表辐射信息的能力,在有云情况下的地表温度反演中明显优于热红外遥感。但云层和除去云层之外的大气,也会对微波信号有影响。以理论分析和模型模拟相结合的方式研究有云大气对AMSR-E(the advanced microwave scanning radiometer-earth observing system)传感器各通道微波信号的影响。结果表明:6.925和10.65 GHz 2个通道可以忽略有云大气的影响;18.7、23.8、36.5和89 GHz 4个通道必须考虑其影响,且它们可以表示成大气可降水量和云中液态水含量的函数。在此基础上,通过进一步分析,选出18.7、23.8和36.5 GHz 3个通道作为将来构建较高精度的被动微波地表温度反演算法的预选通道。

Passive microwave remote sensing has the ability to obtain surface radiation information through clouds,fog,rain,and snow.Therefore,in cloudy weather,it is obviously better than thermal infrared remote sensing in land surface temperature retrieval.However,the clouds and the atmospheric molecules affect the microwave signals to some extent.The effects of cloudy atmosphere on microwave signals in the advanced microwave scanning radiometer-earth observing system（AMSR-E） channels were studied by the way of combining theoretical analysis and model simulation.Results show that the effects can be ignored in 6.925 and 10.65 GHz channels,but cannot be ignored in 18.7,23.8,36.5,and 89 GHz channels.The effects in the last four channels can be expressed as functions of precipitable water vapor and cloud liquid water.Based on the above study and further analysis,three channels,18.7,23.8,and 36.5 GHz,are selected to build a land surface temperature inversion algorithm with higher accuracy.