Sea Ice Retreat Contributes to Projected Increases in Extreme Arctic Ocean Surface Waves

Abstract

The projected changes and trends in the regional annual and monthly maxima of the significant wave height (Hs) in the Arctic Ocean are studied using wave simulations derived from the CMIP5 (Coupled Model Intercomparison Project Phase 5) climate simulations for 1979–2005 and 2081–2100 periods. Under the RCP8.5 scenario, the regional annual maximal Hs increases on average up to ∼3 cm/year, or >0.5%/year, relative to the 1986–2005 climatological value, in many Arctic areas (and up to 0.8%/year in the east side of the Arctic Ocean). While strong winds need to occur for large waves to develop, the changes in wind speed alone cannot explain the increases in the regional maximal Hs. Sea ice retreat also plays an important role by increasing fetch to promote wave growth, thereby contributing notably to the projected increase in wave height. It also contributes to increasing the probability of strong winds over the widening ice-free waters.