一种适用于ASTER数据同时反演大气水汽含量和地表温度的三通道算法

A Three-Channel Algorithm for Retrieving Land Surface Temperature and Atmosphere Water Vapor Content from ASTER Data

提出了针对ASTER数据同时反演大气水汽含量与地表温度的三通道算法,即利用ASTER数据的第12,13,14三个热红外波段建立三个热辐射传输方程。再利用MODTRAN软件分别模拟ASTER 12,13,14波段透过率与大气水汽含量的关系,通过分析可知ASTER三个热红外波段的透过率与大气水汽含量的关系可用近似线性方程表示,从而得到另外三个方程。这样就构成了一个包含六个未知数、六个方程的方程组,形成了针对ASTER数据同时反演大气水汽含量与地表温度的三通道算法。由于各参数都可以通过方程组计算出来,所以,这种算法仅需要ASTER数据就可反演出大气水汽含量与地面温度,且关键参数大气透过率的计算精度提升到了AS-TER数据一个像元(15×15)m2的程度。

A three -channel algorithm is proposed to retrieve land surface temperature and atmosphere water vapor content from AS- TER data at the same time, that is, at first, thee thermal bands （12, 13, 14） of ASTER are utilized to build thermal radiance trans- fer equation. Then MODTRAN software is used to simulate the relationship between atmospheric transmittance and atmospheric water vapor content of thee thermal bands （12,13,14） of ASTER. After analyzing the three thermal infrared bands of ASTER and atmos- pheric water vapor content, three linear equations are obtained, which forms one equation containing six unknown and six equations. And a three - channel algorithm for retrieving land surface temperature and atmosphere water vapor content from ASTER data is formed. Since each parameter can be calculated by equations, this algorithm can retrieve land surface temperature and atmosphere wa- ter vapor content only through ASTER data. And the calculation precision of key parameter atmospheric transmittance comes to one pixel （ 15 ＊ 15m2 ） level.