静止轨道闪电光学探测的光谱选择及影响分析

Spectral Band Selection and Influence Analysis for Lightning Optical Detection for the Geostationary Meteorological Satellite

闪电产生于强对流云或对流云系,是强对流灾害性天气的“示踪器”。闪电成像仪在静止轨道上利用瞬态闪电和缓变的云层、陆地与海洋等背景噪声之间存在时间、空间和光谱特性上的差异,采用光谱滤波、空间滤波、多帧-帧背景去除等三种方法组合来实现瞬态闪电的增强与探测。由于中国缺少云顶闪电辐射、闪电分布、闪电瞬态特性等参数,静止轨道闪电光学探测仪器的设计重点之一是光学探测谱段的选择与评价。针对中国存在的闪电光学性能研究不足和空基天基的光学探测手段较少的情况,在地面采用光谱仪对人工模拟闪电、自然界闪电进行光学特性探测,对获取到的地基闪电光谱数据进行分析和反演,从而得出天基闪电探测的参数选择。文章重点论述了闪电的空间光学探测仪器的探测谱段选取、仿真计算、试验验证等内容,为静止轨道闪电光学探测载荷研制提供基础数据和保障。

Lightning is produced by severe convective clouds or systems, which is a tracer of severe convective weather. The Geostationary Lightning Mapper achieves instantaneous lightning signal intensification and detection from geostationary orbit by using the differences between the lightning signal and the slowly changing background noise such as that of cloud, land and ocean, combining three methods, i.e. spectral filtering, spatial filtering and background noise removal between frames. Due to the lack of parameters of lightning radiation, distribution and transient characteristics of cloud top in China, one of the focuses on the design of the geostationary lightning imager is the spectral band selection and evaluation for the optical detection. At present, there is a lack of research on the optical performance of lightning and the optical detection methods both aircraft-based and space-based are rare in China. Therefore, the optical properties of artificial lightning and natural lightning are detected by spectrometer on the ground, and the obtained ground lightning spectra are then analyzed and retrieved to obtain the spectrum of space-based lightning. In this paper, we discuss the spectral band selection, simulation, calculation and test verification of the geostationary lightning imager, providing basic data and support for the development of the geostationary lightning optical detection camera.