Spatial and temporal variability in pre-monsoon convective activity over Telangana, India

Abstract

 This study examines the interannual variability of pre-monsoon convective activity over Telangana, India, from 1951 to 2024, focusing on its influence on rainfall distribution, rainy days, and associated atmospheric processes. Normalized analysis of rainy days during the March-May (MAM) season reveals above-average pre-monsoon rainfall activity in Strong Convective Years (SCY) (e.g., 1951, 1990, 2006, 2015, 2023) and below-average rainfall activity in Weak Convective Years (WCY) (e.g., 1964, 1965, 1966, 1973, 1984). A marginally increasing trend in pre-monsoon rainfall due to convective activity is observed in recent years. To understand the role of atmospheric processes, composite anomaly analysis is performed for key meteorological variables, including rainfall, rainy days, Convective Available Potential Energy (CAPE), vertically integrated moisture divergence (VIMD), total cloud cover (TCC), total column cloud liquid water (TCLW), solar radiation, and soil water content. Spatial analyses highlight regional variability, showing enhanced pre-monsoon rainfall activity during SCY and suppressed rainfall activity during WCY. Wind patterns at 850 hPa reveal a significant discontinuity over peninsular India, with intensified circulations during SCY and an eastward shift in winds during WCY, emphasizing the role of atmospheric dynamics in modulating convective activity. SCY years exhibit increased atmospheric instability, moisture convergence, cloudiness, and soil water content, along with reduced solar radiation, whereas WCY years show opposite trends. These findings underscore the complex interplay of atmospheric processes driving convective activity and offer critical insights for regional water resource management and climate adaptation. By linking convective activity to broader climatic factors, this study enhances the understanding of pre-monsoon dynamics in Telangana and provides valuable input for forecasting and mitigating extreme weather impacts.