高光谱GIIRS中波通道的最优选择及其对云检测的影响

风云四号A星干涉式大气垂直探测仪（Geostationary Interferometric Infrared Sounder,GIIRS）中波通道的最优选择是有效变分同化此资料的关键技术之一,能减少冗余信息所引起的变分同化和反演的不适定性。将通用的熵减法（Entropy Reduction,ER）用于GIIRS通道优选。此外,由于红外探测器观测容易受云影响,在变分同化GIIRS亮温资料时,需要进行云检测以获得晴空视场点或云参数信息。采用最小剩余法对GIIRS资料开展了云检测研究。该方法不仅能判识视场点是否有云,而且还能得到视场点的有效云量和有效云顶气压信息。但检测精度受不同通道组合的影响,因此基于台风“利奇马（2019）”资料进一步探讨了该影响。

Optimal Selection of Medium-Wave Channels in Hyperspectral GIIRS and Its Influence on Cloud Detection

The optimal selection of medium-wave channels in the geostationary interferometric infrared sounder (GIIRS) of FY-4A is one of the key technologies for effective variational assimilation of the data, which can reduce the ill-posed assimilation and inversion caused by redundant information. In this paper, the general entropy reduction method is applied to GIIRS channel optimization. In addition, since the observations of infrared sounders are easily affected by clouds, cloud detection is needed to obtain field points or cloud parameter information in the clear sky during the variational assimilation of GIIRS bright temperature data. In this paper, the minimum residual method is used to conduct cloud detection of GIIRS data. This method can not only determine whether there are clouds, but also obtain the information of effective cloud amount and cloud top pressure at the field-of-view. Since the detection accuracy is affected by the combination of different channels, the influence based on the data of Typhoon "Lekima (2019)" is further discussed in this paper.