Convective initiation algorithm of Geo-KOMPSAT-2A (GK-2A) Advanced Meteorological Imager (AMI)

Abstract

Geo-KOMPSAT-2A (GK-2A), which is scheduled to be launched in 2018, is a next geostationary satellite of South Korea, following on the Communication, Ocean and Meteorological Satellite (COMS). Advanced Meteorological Imager (AMI) on the GK-2A can scan the Earth with high resolution of both time and space. Furthermore, imageprocessing system of the GK-2A ground system will produce the level 1B images in 2 minutes. Convective Initiation (CI) algorithm can get more accurate weather forecast for heavy rainfall, thunderstorm and lightning through the high resolution of time and spatial data of the GK-2A AMI. Since the convective clouds are usually caused by rapidly developing clouds in unstable atmosphere, they can be detected by the temperature differences between two consecutive images. The CI algorithm of GK-2A AMI has four steps. Convective cloud masking is the first step in the CI algorithm, which extract mature cloud area using infrared channels. The next step is grouping cloud pixels using region growing method for immature cloud area. Then the clustered area (the immature cloud area) will be tested in overlapping detection step in sequential images. The last step of the CI algorithm is “Interest field tests” for each cloud object which can cause severe weather. The CI algorithm was tested by Himawari-8 Advanced Himawari Imager (AHI) data similar to the GK-2A AMI and validated with lightning data and radar observed in ground.