Abstract:

Based on the data of lightning and the CLDAS (CMA Land Data Assimilation System) daily precipitation monitored at the lightning locators in the Greater Khingan Mountains of Inner Mongolia Autonomous Region from 2014 to 2018, the precipitation threshold during the dry lightning period was determined and the data of dry lightning monitoring was screened to analyze the spatio-temporal distribution characteristics of dry lightning in the Greater Khingan Mountains, to provide a scientific basis for the prevention of lightning fire in the Greater Khingan Mountains.The results show that the precipitation error between the CLDAS and meteorological stations in the Greater Khingan Mountains is small and has high applicability, which can meet the demand for dry lightning analysis.The annual average lightning frequency in the Greater Khingan Mountains is 36013.4 times, mainly with the negative ground flash.The annual average lightning days are 110.4 d, of which 42.3% of the amount of daily precipitation is less than 5 mm when the lightning occurs, which should be used as the precipitation threshold when dry lightning occurs in this region.According to the screening of this threshold, the annual average dry lightning occurring in the Greater Khingan Mountains is 1, 5229.8 times.The annual average dry lightning occurs mostly in July.The absolute intensity of the dry lightning current in May and September is stronger.Among the Forestry Services in the region, the intensity of the lightning current is generally strong at these regions including the eastern part of Yong'an Mountain, the south of Mangui, the eastern part of Along Mountain, the northern part of the Khanma Nature Reserve, the eastern part of the Ganhe River, the western part of the Ali River, the northern part of the Jiwen, the southeast of the Poplar, the southern part of Bahrain, the South Wood, and the eastern part of Chao'er, with the annual average dry lightning reaching 0.4 times/km².These regions belong to the high-risk areas for dry lightning.The daily monitoring of dry lightning and the lightning fire prevention work in the above areas should be strengthened.

Key words: Dry lightning, CMA land data assimilation system (CLDAS), Greater Khingan Mountains, Climate response