从红外太阳透过率反演大气可降水量的研究

A Study of Determining Precipitable Water from Solar Infrared Transmission

从红外波段太阳透过率测量中可以反演大气可降水量Ｗ。我们在近、中红外波段．选取了三对波长，用ＬＯＷＴＲＡＮ７辐射传输模式，主要研究了散射和气溶胶对这三对波长反演Ｗ算式的影响。结果表明，通常采用近红外波长对（即０．９４２２～０．８６２μｍ）反演Ｗ并非最佳选择，因为其反演算式受到大气状态（混浊度）的很大影响；而在稍远段两对波长（１．４７～１．５５μｍ和３．７０４～３．０６７μｍ）对应的算式较为稳定。

The precipitable water can be derived from the measurements of solar infrared transmission. Using the LOWTRAN 7 radiative transfer model, the effects of multiple scattering and atmospheric aerosols are investigated on the retrieval algorithm for three pairs of wavelengths in the infrared region. It is shown that: (a) the common use of the pair 0.942￣0.862μm is not optimal for determining precipitable water because the related retrieval algorithm is influenced greatly by the atmospheric turbidity; and (b) the other two pairs chosen by us in the middle infrared region are more suitable for the purpose because of the better stability of their algorithms.