基于GPS和MODIS数据的大气可降水量反演算法研究

Research on Retrieval Algorithm of Atmospheric Precipitable Water Vapor Based on GPS and MODIS Data

基于高精度的PWVGPS与MODIS近红外三通道比值透射率间的关系建立MODIS大气可降水量新反演算法以提高反演精度。利用美国Kansas州和Oklahoma州2009年4月～9月间17期的MODIS数据和对应的SuomiNet网PWVGPS数据进行研究,发现Kaufman和Gao Bo-Cai算法反演的PWVMODIS系统性地偏低于PWVGPS,存在较大的反演误差。以高精度的PWVGPS为标准水汽值,研究PWVGPS与MODIS近红外第19波段的三通道比值透射率间的关系,建立了MODIS大气可降水量新反演算法,并利用研究区数据进行试验验证,结果表明新算法可大幅提高PWVMODIS的反演精度。

The new retrieval algorithm of MODIS atmospheric precipitable water vapor(PWV) was established to improve the retrieval precision based on the relationship between high-precision GPS PWV and MODIS near-IR three-channel ratio transmittance.With the use of MODIS data in Kansas State and Oklahoma State of USA between April and September 2009 and the corresponding SuomiNet GPS PWV,it’s concluded that the MODIS PWV retrieved by Kaufman and Gao Bo-Cai algorithm was systematically lower than GPS PWV with a relatively large error.Setting the high-precision GPS PWV as the standard,the relationship between GPS PWV and MODIS near-IR three-channel ratio transmittance of the 19th channel was researched,and the MODIS PWV new retrieval algorithm was established.Data of the study area was used for experimental verification,which showed that the new algorithm can greatly improve the retrieval precision of MODIS PWV.