Severe convective disasters are the most frequent and widely affected meteorological disasters, causing huge economic losses and posing a serious threat to people and social security. They are also a major threat to new technological fields such as aerospace and information communication. Lightning, as a typical element of global severe convective weather, plays an important role in indicating and warning strong convection. Therefore, lightning detection and warning of severe convective disasters have become one of the important tasks of space remote sensing.

Lightning detection systems mainly include ground-based and space-based detection systems. The ground-based lightning detection system mainly detects and locates broadband electromagnetic radiation signals emitted by lightning strikes, with detection spectral bands mainly including very low frequency (VLF), low frequency (LF), and very high frequency (VHF) bands. The ground-based lightning detection system has developed early and matured in technology, forming a relatively complete business system that plays an important role in lightning warning and forecasting. However, due to the discontinuous station layout of the ground-based lightning detection system and the barrier in mountainous areas, it is unable to effectively carry out uninterrupted lightning detection globally, especially in marine and mountainous areas. In order to overcome the limitations of ground-based lightning detection, space-based lightning detection technology has rapidly developed. The space-based lightning detection system has advantages such as large coverage range and is not limited by ground conditions. Among them, geostationary orbit lightning detection has unique advantages such as 24-hour uninterrupted and high real-time performance, and has become the main direction of international research on space-based lightning detection. It is a priority for the development of space-based lightning detection methods. The ground-based lightning detection system, low orbit and high orbit space-based lightning detection systems, and other lightning detection methods complement each other, achieving 24-hour uninterrupted, high-precision, and real-time detection of lightning, jointly serving strong convective disaster warning and prediction and climate research.

In the research of space-based lightning optical detection, the United States was the earliest to conduct research, with a leading position in depth and breadth. Through the development of low orbit space-based lightning detection cameras optical transient detecter (OTD) and lightning imaging sensor (LIS), the United States ultimately achieved the development of a geostationary orbit lightning detection camera GOES-16 GLM (geostationary lightning mapper), which was launched in November 2016. At the same time, Europe and China directly conducted research and development on geostationary orbit lightning detection cameras. China launched FY-4A LMI (lightning mapping imager) in December 2016, and Europe launched MTG LI (lightning imager) in December 2022. Currently, all three geostationary orbit lightning detection cameras are in orbit.

Due to the fact that lightning usually occurs in strong convective cloud systems, the background formed by reflected sunlight on land, oceans, and clouds has complex, gradual changes, and high-intensity characteristics. Lightning often occurs in areas with clouds, and its intensity and location are random, with short duration and significant differences in intensity. These characteristics make space-based lightning detection cameras significantly different from traditional imaging cameras and point target warning cameras. It has extremely development difficulty (Fig. 9 and 10).

FY-4A LMI is a geostationary orbit FY-4A LMI with independent intellectual property rights, developed by combining the spectral characteristics of background, lightning and its noise (Fig. 13), spatiotemporal characteristics (Fig. 11 and 12), and their variation patterns. It adopts multiple core technologies such as time filtering, spatial filtering, ultra narrowband spectral filtering (Fig. 15), and multi-dimensional fusion point target detection in spacetime and space (Fig. 16). It was launched in December 2016 and applied in orbit meteorological applications. Domestic meteorological departments, numerous research institutes, and universities have utilized the lightning detection results of FY-4A LMI to conduct research and applications on lightning generation and development mechanisms, typhoon monitoring and forecasting, severe convective disaster forecasting, and lightning data assimilation. Accurate prediction and early warning of lightning, severe convective disasters, and their secondary disasters have been achieved (Fig. 18), resulting in huge social and economic benefits and broad application prospects.

China has already achieved the detection and meteorological application of lightning below the troposphere in geostationary orbit, but there is still a significant gap in high-precision positioning, refined detection, intelligent detection, and real-time application of lightning below the troposphere. At the same time, China has not yet established an effective atmospheric lightning in the stratosphere, mesosphere and thermosphere (TLEs, transient luminous events) detection system, especially a space-based detection system that has not been planned. Therefore, in the field of lightning below the troposphere detection, we should gradually develop towards three-dimensional high-precision detection, intelligent detection, on-demand independent planning and application closed-loop. In the detection of lightning in the stratosphere, mesosphere and thermosphere (TLEs), research on detection methods and cameras should be carried out in the future to achieve real-time detection and early warning, serving the safety guarantee of China's entry and exiting into the atmosphere and space-based spacecraft.