Projected Warming and Extreme Precipitation Changes across the Himalayan Arc Using WRF Regional Climate Simulations

Abstract The Himalayan region is highly vulnerable to climate change due to its complex topography, strong elevation gradients, and interactions between monsoonal and extratropical circulation systems, which remain inadequately resolved in coarse-resolution global climate models. To address this issue, this study uses high-resolution (9 km) dynamical downscaling with the Weather Research and Forecasting (WRF) model, driven by bias-adjusted Max Planck Institute Earth System Model (MPI-ESM-HR) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations, to assess the projected changes in temperature, precipitation, and extreme precipitation across the Western, Central, and Eastern Himalaya under SSP2-4.5 and SSP5-8.5 scenarios. Model evaluation against multiple observational and reanalysis datasets demonstrates good agreement in reproducing historical spatial patterns, seasonal variability, and elevation-dependent temperature gradients across the Himalayan region. Results indicate widespread warming across the Himalaya during 2031–2060, with temperature increases of approximately 1–2°C under Shared Socioeconomic Pathway 2-4.5 (SSP2-4.5) and 2–4°C under Shared Socioeconomic Pathway 5-8.5 (SSP5-8.5), with stronger warming at higher elevations and over the northern Himalayan ranges. Precipitation projections show strong spatial and seasonal heterogeneity. Annual precipitation increases by approximately 10–40% during the near-future period (2031–2045) across parts of the western and central Himalaya, while late-future (2046–2060) changes become more spatially heterogeneous, with precipitation decreases of nearly 10–20% over parts of Himachal Pradesh, Uttarakhand, and adjoining plains. Results further show that extreme precipitation intensifies despite spatially heterogeneous changes in mean precipitation. Rx1day and Rx5day increase by approximately 5–15 mm, with localized increases exceeding 15 mm under SSP5-8.5. The frequency of extreme precipitation events increases by 2–6 days yr⁻¹, while their contribution to annual precipitation rises by approximately 2–10%, particularly across the Western Himalaya and mid-elevation zones. These findings highlight strong regional and elevation-dependent hydroclimatic changes and demonstrate the value of high-resolution dynamical downscaling for improving future climate risk assessments at fine spatial scales across the Himalayan region.