FY-3A气象卫星红外分光计温度廓线模拟反演试验

EXPERIMENTS WITH ATMOSPHERIC TEMPERATURE PROFILE RETRIEVAL FROM FY-3A IRAS SOUNDINGS

为了考察风云三号(FY-3)气象卫星红外分光计的性能,以该仪器初样阶段的光谱通道特征和仪器响应函数为基础,进行大气温度垂直廓线模拟反演。选用红外分光计15μmCO2吸收带的不同通道组合进行模拟反演,结果表明:总体上红外分光计具有较好的大气温度反演能力,窗区通道8的加入可有效提高近地面层温度反演精度;利用迭代算法反演大气温度时,初估廓线对反演精度影响较大,初估廓线与真值愈接近,反演精度愈高;现有仪器通道灵敏度设计指标可满足大气温度反演基本要求,如仪器灵敏度降低,反演精度也随之降低,提高仪器灵敏度,有利于提高仪器的使用效果。

To investigate the performance of InfRared Atmospheric Sounder （IRAS） aboard the satellite FY-3A, the retrieval of the vertical profile of atmospheric temperature is studied based upon the IRAS channel spectral characteristics in its initial design and the spectral response function of the spectrometer. The retrieval is performed using different combinations of channels for 15 μm CO2 absorption bands of the IRAS, indicating that on the whole the sounder produces higher retrieval and inclusion of channel 8 leads to the remarkable improvement of retrieval precision of near-surface-layer temperature. For the retrieval from an iterative algorithm the first guess profile affects the precision greatly, and the closer the estimated profile to the true value, the higher the accuracy. The designed channel sensitivity meets the required needs of such retrieval. Low sensitivity leads to lowered precision. As a result, the retrieval precision depends strongly on the IRAS sensitivity.