Investigating spatio-temporal association between lightning, aerosols and cloud characteristics over India using multi-satellite observations and reanalysis datasets.

Lightning has been one of the fatal extreme weather phenomena in the Indian subcontinentwith a high mortality rate. It is associated with meteorological processes that influence athunderstorm's thermodynamic properties. In this study, we investigate the possible linkagesbetween spatio-temporal characteristics of lightning intensity and aerosol and cloud propertiesover the Indian region using multi-satellite observations and reanalysis datasets. We usedInternational Space Station (ISS) based Lightning Imaging Sensor (LIS) data (resolution 4-8km) for the available period (2017-2020). Compared to its predecessor Tropical RainfallMeasuring Mission (TRMM), ISS-LIS covers a larger latitudinal extent (55 o N to 55 o S). Pre-monsoon (MAM) and summer monsoon (JJAS) are the two seasons when lightning is mostcommon over the Indian region, with flash rates reaching up to 40-45 flashes per squarekilometer in the north-eastern and northern parts of India. As aerosols are known to modifycloud properties, changing emissions of aerosols can be expected to affect lightning flashrates.To assess the role of aerosols, we analyzed aerosol optical depth or AOD (0.5°×0.625°)hourly data from Modern-Era Retrospective Analysis for Research and Application(MERRA)-2 dataset. We further employed half-hourly high spatial resolution (10kmx10km)data from the Indian Geostationary Satellite (INSAT) to better understand cloudcharacteristics such as Cloud Optical Depth (COD), Cloud Effective radius (CER), andOutgoing Longwave Radiation (OLR), etc. during the lightning periods. We choose gridswith at least one recorded lightning flash incident on a given day. Results of our analysisshow that lightning flash rates exhibit a positive relationship with the increase in AOD up to0.5. In nearly 75 % of grids where lighting is noted, the OLR values are found to vary in therange (100-200) W/m2, which confirms the existence of deeper clouds associated withlightning. Nearly 60% of lightning grids are found to exhibit high COD values (~25-30).More region-specific spatio-temporal features regarding the association between aerosols,clouds, and lightning flashes over the Indian region will be presented.