Unravelling the future role of internal variability in South Asian near-surface wind speed

Abstract. Near-surface wind speed (NSWS) plays a critical role in water evaporation, air quality, and energy production. However, changes in NSWS over South Asia, a densely populated and climate-sensitive region, remain underexplored. This study aims to assess and quantify the uncertainties in NSWS projections over South Asia, with a focus on internal variability. Using a 100-member large ensemble from the Max Planck Institute Earth System Model, we identified the Interdecadal Pacific Oscillation (IPO) as the dominant climate mode of internal variability affecting NSWS in the near future. Our results show that the positive phase of the IPO enhances regional westerly winds, leading to an increase in NSWS. Importantly, accounting for the influence of the IPO reduces projection uncertainty of NSWS by up to 8 % in the near future and 15 % in the far future. These findings highlight the critical role of internal variability, especially the IPO, in modulating regional NSWS projections. By narrowing uncertainties, this work supports improved planning for climate adaptation and wind energy development in South Asia.