Raindrop Size Distribution Analysis in Active vs. Break Spells of Summer Monsoon from 2018 to 2021 over Rourkela

Abstract

This study analyzed Raindrop Size Distributions (RSD) of summer monsoon rainfall over eastern India from 2018 to 2021. Raindrops were divided into small, medium-sized drops, and large-sized drops. The findings reveal that all-sized drops were more prevalent during active spells than break spells. The Probability Distribution Function (PDF) of rain rate (R) and liquid water content (log10W), mass-weighted mean diameter (Dm), and Normalized intercept parameter (log10Nw) were analyzed. PDF of R and log10W showed a higher frequency during break spells but higher values during active spells. Conversely, the Dm and the log10Nw exhibited higher frequency and values during active spells. Convective precipitation was higher than stratiform precipitation in both active and break spells. Distinct differences between active and break spells were observed in the radar reflectivity-rainfall rate (Z–R) relation and the shape and slope (μ–Λ) relation. The presence of higher concentrations of raindrops of all sizes and the dominance of convective precipitation during active spells can be attributed to the increased Convective Available Potential Energy (CAPE) and greater liquid water content during active spells.