Atmospheric Dynamics related to Precipitation Microphysics near Land-Sea Boundaries: A Comparative Analysis of Monsoon Season in Eastern and Western Regions of India

This study explores the complex interaction among atmospheric parameters, encompassing instability, airflow patterns, and aerosol environments, impacting cloud microphysics and, consequently, the range of raindrop sizes during the monsoon season (June-September) in the land-sea regions of eastern and western India-namely, Kolkata $\left(22.57^{\circ} \mathrm{N}, 88.37^{\circ} \mathrm{E}\right)$ and Desalpar $\left(23.20^{\circ} \mathrm{N}\right.$, $69.44^{\circ} \mathrm{E}$). In Kolkata, characterized by enhanced atmospheric instabilities, larger raindrops prevail than in Desalpar. The airflow patterns and local anthropogenic activities govern the prevalence of aerosol types and cloud features in these two locations. Notably, there is a significant contrast in aerosol compositions; Kolkata exhibits a higher concentration of sulfate aerosols, while Desalpar is characterized by dust and sea salt aerosols. This investigation highlights that, during the monsoon season, areas with a larger cloud-effective radius tend to experience a prevalence of smaller raindrop sizes. The pronounced variability in the raindrop size spectrum underscores the importance of establishing location-specific radar reflectivity $(Z)$ - rain rate $(R)$ relationships for reliable radar estimation of rain rates.