Evolving Rainfall Extremes in the Indian Ganga Basin
The research group of Dr. Somil Swarnkar, Department of Earth & Environmental Sciences, developed a conceptual multivariate–probabilistic framework to understand evolving rainfall extremes in the Indian Ganga Basin (IGB). The framework integrates long-term rainfall records (1901–2023) to systematically assess changes in rain spell behavior. The process begins with the identification of rainfall extremes, followed by the extraction of key rain spell characteristics, i.e., duration, intensity, and volume. These variables are jointly analyzed to distinguish short-duration (1–3 days) and long-duration (>3 days) events. A joint probability-based severity index is then developed to quantify compound rainfall behavior, capturing interactions among multiple characteristics. Further, a first-order Markov chain approach is applied to evaluate rainfall persistence and transition dynamics between wet and dry states, enabling the identification of shifts in rainfall regimes over time. The framework reveals a transition toward more frequent, intense, and fragmented short-duration rainfall events across the basin. These changes have significant hydrological implications, including increased flash floods, surface runoff, soil erosion, and landslide risks, along with reduced groundwater recharge. The framework provides a robust scientific basis for hydroclimatic risk assessment and supports climate-adaptive water resource management in the Indian Ganga Basin. For more details, kindly visit https://www.sciencedirect.com/science/article/pii/S0169809526002681?via=ihub
