Complex Surface Microwave Emissivity Model Applied Research In The Grapes

This article is composed of seven sections. In the first section, the background and the research progress of land emissivity calculation are given. In the second section, Weng's microwave land emissivity model is introduced, and the sensitivity of the various land emissivities to its parameters is tested. In the third section, based on radiation transmission theory, the impact of land emissivity on the brightness temperature emitted by earth-atmosphere is deduced. The result is that the impact is depended on the atmosphere transmissivity. In the forth section, the impact of land on the brightness temperature at AMSU-A's channels are calculated by RTTOV-7, and the calculation makes clear that at the atmospheric windows channel, the emissivity has much impacts on the brightness temperature. In the fifth section, in order to find out the character of the impact of various land emissivities on brightness temperature, the sensitivity of radiation measured by satellite to the land emissivity is tested in GRAPES's 3D-Var system. In the sixth section, putting Weng's microwave land emissivity model in GRAPES's 3D-Var system, calculating the R.M.S. of brightness temperatures. As the result is not so good, combining with NOAA/NESDIS's land algorithms for emissivities at three AMSU channels, the adjusting parameters scheme has been given out. And the result is better than before. Otherwise, the result is much better under the snow surface after using Weng's microwave snow emissivity model. In the seventh section, we summarized our research and put up the shortages of this article.