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Regional variability in lightning activity over South Asia
International Journal of Climatology ( IF 3.5 ) Pub Date : 2020-05-09 , DOI: 10.1002/joc.6641
Adarsh Kumar Kamra 1 , Penki Ramesh Kumar 2
Affiliation  

The regional variability of lightning activity over 10 different regions, selected with at least one major meteorological/topographical feature, of South Asia (8°N–36°N, 90°E–100°E) have been examined on all time scales from the data obtained from July 1995 to December 2013 from the Tropical Rainfall Measuring Mission satellite. A comparative study of the correlation coefficients calculated between lightning flash rate and convective parameters, aerosol optical depth (AOD) and topography for different regions is carried out. Impact of the progress of the Asian Monsoon on the spatio‐temporal variability of flash rate is also examined. Monthly‐averaged variations are annual at the regions >2,700 m in altitude and are semi‐annual at the regions <2,700 m in altitude. The annually averaged flash rates increase during the study period in most of the regions. However, such long‐term changes are nonlinearly related to the change in convective parameters and AOD and such inter‐relationships differ from one meteorological region to another. Small changes in AOD in high altitude regions are associated with very large changes in the surface temperature and flash rate. The flash rate is strongly correlated with surface temperature in the dry region of the north‐west but with CAPE in moist region of the north‐east. Progress of the Asian monsoon strongly impacts the flash rate in different regions. Ratio of the amplitudes of primary to secondary maxima at land stations increases with latitude in case of the monthly‐averaged variations in flash rate. The primary maxima in these variations are highly correlated with the atmospheric surface temperature. However, the secondary maxima are associated with the low‐level convergence during the withdrawal phase of the monsoon. Incursion of moisture by the Bay of Bengal branch of monsoon current determines the sequence of occurrence of lightning activity in different regions along the Himalayan foothills and north‐west.

中文翻译:

南亚闪电活动的区域差异

在所有时间尺度上,对南亚的至少10个不同地区(至少具有一种主要的气象/地形特征)(8°N–36°N,90°E–100°E)选择的闪电活动的区域变异性进行了研究。 1995年7月至2013年12月从热带雨量测量任务卫星获得的数据。对不同区域的闪电闪光率与对流参数,气溶胶光学深度(AOD)和地形之间的相关系数进行了比较研究。还研究了亚洲季风的进展对闪速的时空变化的影响。月平均变化在海拔> 2,700 m的区域是每年的,而半年变化在海拔<2,700 m的区域是半年的。在研究期内,大多数地区的年平均闪光率都在增加。但是,这种长期变化与对流参数和AOD的变化呈非线性关系,而且每个气象区域之间的相互关系也不同。高海拔地区AOD的微小变化与地表温度和闪速的很大变化有关。闪速与西北干旱地区的地表温度密切相关,而与东北潮湿地区的CAPE密切相关。亚洲季风的发展强烈影响着不同地区的闪速。在地面平均站最大一次和第二次最大振幅振幅之比随纬度的增加而增加,这是闪速每月平均变化的情况。这些变化的主要最大值与大气表面温度高度相关。然而,次要最大值与季风退缩阶段的低层收敛有关。季风流的孟加拉湾分支对湿气的入侵决定了喜马拉雅山麓和西北部不同地区闪电活动的发生顺序。
更新日期:2020-05-09
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