Assessing high-resolution precipitation extremes in Central Asia: evaluation and future projections

The sustainability of ecosystems in Central Asia's semi-arid and arid regions is increasingly threatened by anthropogenic climate change, with shifts in extreme precipitation events playing a pivotal role. Effective adaptation strategies depend on precise forecasting of these changes. This study investigates projected trends in mean and extreme precipitation indices across Central Asia (CA) from 1985 to 2100. Utilizing datasets from the fifth generation of ECMWF Reanalysis (ERA5), the Climate Prediction Center (CPC), and high-resolution National Aeronautics and Space Administration (NASA) Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) derived from Coupled Model Intercomparison Project Phase 6 (CMIP6) models, we analyzed four Shared Socioeconomic Pathway (SSP) scenarios across three distinct time periods. The CMIP6 Multi-Model Ensemble (MME) accurately simulates mean annual precipitation (ANP) for much of the region, though it underperforms in mountainous areas. Specifically, it underestimates days with precipitation exceeding 10 mm (PD10MM) and the Simple Daily Intensity Index (SDII) while overestimating Consecutive Dry Days (CDD) in regions with higher altitudes and more precipitation. Projections indicate a potential increase in mean ANP by up to 50% across most of Central Asia, becoming especially prominent from the mid-century onward. Extremes in precipitation, such as the SDII, the maximum 1-day precipitation amount (RX1DAY), and days with over 10 mm of rainfall, are expected to rise in frequency and intensity across the region. In contrast, while CDD may decrease in eastern CA, it will likely increase in the west by the century's end. These anticipated changes suggest increased wetness under warming scenarios, with more frequent heavy precipitation events and a reduction in prolonged dry periods, particularly under high-emission pathways. The data provides a foundation for developing effective adaptation strategies to enhance resilience against the impacts of climate change in Central Asia.