The El Niño–Southern Oscillation (ENSO) modulates the lightning flash density (LFD) variability over India during premonsoon, monsoon and postmonsoon seasons. This study intends to shed light on the impact of ENSO phases on the LFD over the Indian subcontinent using the data obtained from Optical Transient Detector (OTD) and Lightning Imaging Sensors (LIS) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite. Results suggest the LFD over northeast India (NEI) and southern peninsular India (SPI) strengthened (weakened) during the warm (cold) phase of ENSO in the premonsoon season. During monsoon season, NNWI (north of northwest India) shows above (below) normal LFD in the cold (warm) ENSO phase. It is striking to note that there are three hot spots of LFD over the Indian land region which became more prominent during the monsoon seasons of the last decade. A widespread increase in LFD is observed all over India during the warm phase of ENSO in the postmonsoon season. A robust rise in graupel/snow concentration is found during the postmonsoon season over SPI in the ENSO warm phase, with the lowest fluctuations over the NEI and NNWI regions. The subtropical westerly jet stream is shifted south in association with the warm phase, accompanied by an increase in geopotential height (GPH) all over India for the same period. This exciting remark may explain the indirect influences of ENSO's warm phase on LFD during the postmonsoon season by pushing the mean position of the subtropical westerly towards southern latitudes. However, the marked increase in LFD is confined mostly over the NNWI in the cold ENSO phase.

中文翻译：

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印度地区雷电灾害相对于厄尔尼诺-南方涛动 (ENSO) 阶段的变化

厄尔尼诺-南方涛动 (ENSO) 调节了印度在季风前、季风和季风后季节的闪电密度 (LFD) 变化。本研究旨在利用从热带降雨测量任务 (TRMM) 卫星上的光学瞬态探测器 (OTD) 和闪电成像传感器 (LIS) 获得的数据，阐明 ENSO 相位对印度次大陆 LFD 的影响。结果表明，在季风前季的 ENSO 暖（冷）阶段，印度东北部（NEI）和印度半岛南部（SPI）的 LFD 增强（减弱）。在季风季节，NNWI（印度西北部以北）在冷（暖）ENSO 阶段显示高于（低于）正常 LFD。值得注意的是，印度陆地区域有三个 LFD 热点，在过去十年的季风季节变得更加突出。在后季风季节的 ENSO 温暖阶段，在印度各地观察到 LFD 普遍增加。在 ENSO 温暖阶段的 SPI 的季风后季节期间，发现了霰/雪浓度的强劲上升，NEI 和 NNWI 地区的波动最小。副热带西风急流随着暖期向南移动，同时印度各地的位势高度（GPH）增加。这一令人兴奋的评论可能解释了 ENSO 的暖相在季风后季通过将副热带西风的平均位置推向南纬而对 LFD 的间接影响。然而，