Abstract
<title>Abstract</title> <p>Rainfall and cloud properties along with microphysical characteristics are less known over the island regions of India. The present study examines the spatial distribution of climatological rainfall characteristics, rainfall amount (RA), rainfall frequency (RF), and rainfall rate (RR), along with the vertical structure of precipitation. We use 16 years (1998–2013) of TRMM precipitation radar data at ~ 5 km × 5 km resolution during the summer monsoon season (June–September) over the Lakshadweep region. In addition, rainfall microphysical features are examined using disdrometer data collected at Agatti Island during the 2024 summer monsoon. Climatological RA ranges from 6–12 mm/day across the islands and is relatively higher over the eastern islands. RF follows similar pattern while RR shows contrasting distribution of localized pockets of high values. While total rainfall is contributed by both RF and RR, RF plays dominant role. Frequency distribution of echo top heights (ETH) shows bimodal nature (4 km and 6 km); more than 60% of the precipitating clouds have ETH between 5–8 km. Though TRMM broadly provides convective-stratiform classification, we reclassify the precipitating clouds into 4 categories, deep convective, pure stratiform, mixed and shallow convective. Our analysis reveals that Lakshadweep region is strongly dominated by stratiform-like precipitation, associated with mixed and stratiform clouds, accounting for 75% occurrences and nearly 70% of the total rainfall. The remaining precipitation is associated with shallow and deep convective clouds, which account for 20% and 5% occurrences and contribute about 16% and 15% of the total rainfall, respectively. Rainfall microphysical features show bimodal distributions of mass-weighted drop diameter (Dm) and generalized intercept parameter (Nw). Modes for Dm occur at 1-1.2 mm and 1.6 mm while those for log10(Nw) occur at 3.2 and 3.8. Diurnal variations of RR and Dm are weak and show complex pattern with multiple peaks, primarily during nocturnal and late evening hours. Background atmospheric conditions show dry air intrusion at mid-tropospheric levels in the offshore Arabian sea along with high CAPE and CIN values compared to the coastal region, which influence cloud development in this region.</p>