Future trends of arctic surface wind speeds and their relationship with sea ice in CMIP5 climate model simulations

Stephen J Vavrus,Ramdane Alkama

doi:10.1007/s00382-021-06071-6

Stephen J Vavrus, Ramdane Alkama

Open Access

https://doi.org/10.1007/s00382-021-06071-6

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Abstract

Recent climate change in the Arctic has been rapid and dramatic, leading to numerous physical and societal consequences. Many studies have investigated these ongoing and projected future changes across a range of climatic variables, but surprisingly little attention has been paid to wind speed, despite its known importance for sea ice motion, ocean wave heights, and coastal erosion. Here we analyzed future trends in Arctic surface wind speed and its relationship with sea ice cover among CMIP5 global climate models. There is a strong anticorrelation between climatological sea ice concentration and wind speed in the early 21st-century reference climate, and the vast majority of models simulate widespread future strengthening of surface winds over the Arctic Ocean (annual multi-model mean trend of up to 0.8 m s−1 or 13%). Nearly all models produce an inverse relationship between projected changes in sea ice cover and wind speed, such that grid cells with virtually total ice loss almost always experience stronger winds. Consistent with the largest regional ice losses during autumn and winter, the greatest increases in future wind speeds are expected during these two seasons, with localized strengthening up to 23%. As in other studies, stronger surface winds cannot be attributed to tighter pressure gradients but rather to some combination of weakened atmospheric stability and reduced surface roughness as the surface warms and melts. The intermodel spread of wind speed changes, as expressed by the two most contrasting model results, appears to stem from differences in the treatment of surface roughness.

Highlights

The Arctic is undergoing a dramatic transformation in response to the warming climate, with serious societal and environmental consequences
This strongly inverse relationship between wind strength and sea ice coverage suggests that the emergence of open water as Arctic sea ice retreats in the future could coincide with increased wind speeds
The results demonstrate a robust future response of stronger surface winds over initially seaice covered regions in the Coupled Model Intercomparison Phase 5 (CMIP5) models, over the Arctic Ocean, with only one pair of closely related global climate models (GCMs) exhibiting a distinctly contrarian trend toward weaker winds

Summary

Introduction

The Arctic is undergoing a dramatic transformation in response to the warming climate, with serious societal and environmental consequences. A number recent studies have shown convincing evidence of increasing surface wind speeds or wave heights over the Arctic Ocean as the region warms (Spreen et al 2011; Stegall and Zhang 2012; Wang et al 2015; Zhang et al 2018; Waseda et al.2018, Jakobson et al 2019), and these trends are expected to continue in the future (McInnis et al 2011; Dobrynin et al 2012; Khon et al 2014; Aksenov et al 2015; Ruosteenoja et al 2019) Most of these prior studies were limited by focusing only on a single season or region of the Arctic, and they did not address the cause of the strengthened winds. Alkama et al (2020) applied a combination of atmospheric reanalyses and climate model output from the Coupled Model Intercomparison Phase 5 (CMIP5) to document relationships between sea ice concentration and surface wind velocity during the historical record Their analysis revealed bidirectional causality, such that ice loss promotes stronger winds (especially poleward) and vice versa, and it suggests that future sea ice loss will foster enhanced surface winds. (3) If models do generally simulate stronger winds, what are the physical causes? If not, what explains the inter-model disagreement?

Data and Methods

Recent conditions

Discussion and Conclusions