Spatio-temporal variability of lightning activity over the Indian region

[1] Spatio-temporal variability of lightning activity over the Indian land mass region (8 degrees N - 33 degrees N, 73 degrees E - 86 degrees E) has been studied using monthly satellite based lightning flash grid (5 degrees x 5 degrees) data for 5-year ( 1998 - 2002) period. These data have been examined for depicting the annual, seasonal, and spatial distribution of the lightning activity. The study revealed the nonlinear relationship between lightning flash density and latitude on the annual timescale, and it is linked with the convective activity, large-scale circulations, land mass gradient, and orography of the region under study. On the seasonal timescale, the nonlinear positive relationships were observed in the premonsoon and monsoon seasons whereas a bimodal variation is observed in the post-monsoon season. The comparison of flash density with maximum surface air temperature shows the existence of nonlinear relationship between the two parameters. The approximate range of increase of flash density per 1 degrees C rise in temperature is 20 to 44%. The lightning flash density shows a pronounced semiannual oscillation over the latitude belts 8 degrees N - 28 degrees N.