FY-3A气象卫星红外分光计透射率计算及大气参数模拟反演试验

【作者】 漆成莉；

【导师】 董超华； 张文建；

【作者基本信息】 中国气象科学研究院 ， 大气物理与大气环境， 2004， 硕士

【摘要】 风云三号气象卫星是我国的第二代极轨气象卫星。它将首次携带红外分光计（IRAS）、微波温度计、微波湿度计三个大气垂直探测仪器。为了配合仪器IRAS的正样研制，需要做一系列的模拟试验工作来检验仪器性能指标参数，以保障卫星上天后IRAS的正常运行和仪器资料的正常应用。 本文以IRAS初样阶段的光谱通道特征和仪器响应函数为基础，利用GENLN2逐线光谱透射率数据库和参数化快速辐射传输模式RTTOV7计算IRAS各通道光谱透射率系数，并对系数进行了检验；结合实际大气计算了IRAS的通道透射率及权重函数，并与国外类似仪器—高分辨率红外大气探测器（HIRS／3）相应结果进行了比较分析；为了进一步检验正演结果，本文还以典型大气为输入廓线，计算到达卫星IRAS的通道辐射率测值，并与HIRS／3相应结果进行比较。结果表明，IRAS的快速透射率系数比较精确，计算的透射率精度较高，基本反映了仪器特性；IRAS各通道的透射率及权重函数曲线分布基本合理，辐射能量峰值高度层等指标基本满足设计要求，个别通道权重函数峰值高度与设计的比，有所抬升；IRAS各通道的卫星测值模拟结果合理，可用于今后的大气温度反演。通过上述计算研究工作，使我们对我国新一代极轨气象卫星IRAS仪器光谱通道各气压层能量贡献分布有了较细致的了解，对仪器研制工作有一定的指导意义，同时为卫星上天后该仪器资料的处理奠定了良好的基础。 本文利用IRAS的透射率计算结果，还进行了大气温度模拟反演的一系列敏感性试验，包括通道组合、物理反演方法的初估廓线选择和仪器通道灵敏度对温度反演的影响等。结果表明，IRAS前7个CO₂通道具有反演大气温度廓线的能力，窗区通道8可有效提高近地面层温度反演精度；迭代反演法对温度层结的反演修正能力与透射率权重函数的峰值高度有很大相关性；各通道现有的噪声设计水平基本可满足大气温度反演，但若降低仪器灵敏度，大气温度反演精度也会随之降低。从模拟研究结果看，总体上IRAS具有较好的大气温度反演能力。更多还原

【Abstract】 FY-3 meteorological satellite is the second generation of polar-orbit meteorological satellite in China, it will carry InfRared Atmospheric Sounder (IRAS)? Microwave Atmospheric Sounder, Microwave Atmospheric Humidity Sounder for the first time. In order to provide some helpful information to the IRAS’ manufacturer, much simulation should be done to verify the characteristics of IRAS so that the satellite can be in good working state and the satellite data can be useful.This paper bases on the characteristics and spectral response function of the primary ERAS sounding channels and GENLN2 line-by-line spectral transmittance database, calculates the fast radiative transfer model’s (RTTOV7) transmittance coefficients and verify them. We also calculate some atmospheric profiles’ channel transmittance and weighting function as well as the simulating satellite observed radiance then compare the results with High Resolution Infrared Sounder (HIRS).It shows that the IRAS’ transmittance coefficients is satisfying, the channel transmittance and weighting function curves are reasonable, they have little differences from that of HIRS, can indicate the contribution of each atmospheric layer make to the upwelling radiance from the whole atmosphere. The levels of peak energy contribution were mostly consistent with the prepositional target, although some channels’peak-levels are a little raised from the design object; the variety trend is consistent with HIRS/3 instrument. IRAS’ simulating channel observed radiance also has little differences from that of HIRS and it can be used in the temperature profile retrieval.Under the calculation results of IRAS’ channel transmittance, the paper performs sensitivity tests of temperature profile retrieval. These tests are about how do different channel groups; different guess profile and different instrument noise influence the temperature profile retrieval. Through the results we know the IRAS’ invert precision is associated with the peak-levels of the transmittance weighting function. The designed noises can be used to retrieve temperature profile, but if it is enlarged the invert precision will be reduced. As a whole, the ability of temperature profile retrieval from ERAS’ simulated measurement is acceptable.更多还原