Spatial and Temporal Distribution of Lightning Activities on the Tibetan Plateau

We study the spatial and temporal distribution of lightning flash activity and its response to the thermodynamic characteristics on the Tibetan plateau by using the composite gridded lightning data from 1995 to 2002 observed by the satellite-based sensors, provided by NASA LIS/OTD Science Team in Marshall Space Flight Center. The result shows that the mean flash density on the Tibetan plateau was 3 fl·a−1·km−2, and the maximum flash activity was on the central Plateau around (32°N, 88°E) with a peak value of 5.1 fl·a−1·km−2. The flash activity on the Plateau exhibited a seasonal variation and mainly occurred from June to August with a maximum flash activity period from late June to middle July. The diurnal variation of the maximum flash rate peaked during 14:00~16:00LT with exceptions of the prominent high mountain region, which peaked earlier, and prominent low basins, which peaked later. The flash activity on the Plateau strongly depends on the ground thermodynamic characteristics, and a positive correlation between lightning activity and Bowen ratio and ground sensitive heat flux is found during the plateau monsoon season. The correlation coefficient is 0.7 and 0.6, respectively, and the Bowen ratio could be an indicator of lightning producing efficiency.