Role of Water Balance Components in Regulating Vegetation Response to Drought

Droughts across India exhibit variability arising from the complex interaction between atmospheric forcing and terrestrial hydrological processes. Although precipitation deficits are generally considered the primary trigger for drought, changes in terrestrial water storage dictate how drought evolves and recovers. It is therefore essential to understand how surplus and deficits in water balance governs not only the drought periods across different hydroclimatic zones of India but also the subsequent influence on vegetation health. In this study, we analyze how water balance components regulate vegetation by assessing the elasticity of vegetation to climatic and catchment storage variables. A dominant driver approach is used to evaluate whether vegetation response is mainly controlled by meteorological or terrestrial variability. Furthermore, we analyzed the influence of key drought attributes, including severity, duration, development and recovery speeds, on vegetation elasticity with respect to climate and catchment variables. The results show a shift from precipitation-dominated vegetation control during mild drought conditions to storage-driven regulation under extreme droughts. These findings highlight the role of subsurface water storage in buffering vegetation against severe drought stress across India. Overall, this analysis offers valuable insights into the processes controlling vegetation resilience and susceptibility, allowing for a more refined understanding of vegetation-catchment-climate interactions across diverse drought conditions.