Abstract ID: 3.13804 | Accepted as Talk | Talk/Oral | TBA | TBA

The Himalayas, a tectonically active, topographically complex, and strong modulator of weather and climate patterns over high mountain Asia, are highly vulnerable to a number of natural hazards, including extreme precipitation events (EPEs), which are exacerbated by climate change. Such events introduce significant losses to life, infrastructure, agriculture, and, in turn, the region’s economy. This paper provides an assessment of long-term (1951–2023) precipitation extremes and projections (2024-2090) over the Himalayan Ganga Basin (HGB) using state-of-the-art, high-resolution Indian Meteorological Department (IMD) and statistically downscaled NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) during southwest monsoon season (JJAS) under different scenarios (SSPs). The data includes historical data (1951–2023) and future projections (2024–2090) from various global climate models (GCMs). The selected extreme precipitation indices are classified into intensity, frequency, and duration measures. The findings reveal geographically heterogeneous and mixed trends among different scenarios with clustering in Dehradun and Ukhimath; however, extremes are intensifying and becoming more frequent over the years in the region during both seasons, although large numbers of 1-day EPEs have been recorded during the decade 1961–1970. The change in rainfall in the northern parts of the basin is relatively higher than that in the southern parts of the basin. Stations at higher altitudes recorded extreme rainfall during the October and January months, whereas plain area stations recorded extreme rainfall during the June to September monsoon months. The results also suggest that monsoon rainfall in the region could increase in the near future and more significantly in the far future, with the amount of rainfall during the monsoon season expected to rise under both scenarios. Extreme rainfall events, such as the highest 1-day and 5-day rainfall, are projected to become more frequent, while the number of dry days in between is expected to decrease. These findings highlight the importance of planning for more intense and frequent rainfall in future climate resilience efforts in the region.