Attributing Variations of Winter and Summer Near Surface Wind Speeds Over the Arctic Ocean

Abstract

Changes in near surface wind speeds (NSWS) over the Arctic Ocean play a critical role in regulating sea ice drift, the surface energy budget, and sea ice‐atmosphere interactions. However, the drivers behind their long‐term variability and trends remain poorly understood. Here, we use ERA5 reanalysis and CESM2 simulations to quantify the relative contributions of internal variability and external forcing to winter and summer NSWS changes since 1940. While NSWS in both seasons exhibit significant increasing trends during 1940–2014, their underlying mechanisms differ. External forcing explains about 60% of winter NSWS variations. In contrast, summer NSWS variability is largely controlled by internal climate variability. Furthermore, the dominant external forcing affecting winter NSWS shifts around 1970: anthropogenic aerosols are the main driver before 1970, whereas greenhouse gases prevail afterward. These findings underscore that the distinct physical processes govern seasonal Arctic NSWS variability, thereby improving our understanding of regional climate evolution.