The Impacts of Climate Change on the Autumn North Atlantic Wave Climate

Abstract

In this study, we investigate the impact of global warming induced by possible climate change on the autumn winds, the related storm climate, and the wave climate over the North Atlantic Ocean. These analyses are based on a third-generation wave model, WAVEWATCHIII? and dynamically downscaled winds, obtained from the Canadian Regional Climate Model driven by the third version of the Coupled Global Climate Model (T47) from the Canadian Centre for Climate Modelling and Analysis following the A1B climate change scenario of the Special Report on Emission Scenarios from the Intergovernmental Panel on Climate Change. Compared with the present wave climate, represented as 1970–1999, the significant wave heights in the northeast North Atlantic will increase, whereas in other areas, such as the mid-latitudes, they will decrease, with associated changes in winds in the future climate (2040–2069). An analysis of inverse wave ages is used to suggest that wind-driven wave regimes tend to occur more frequently in the northeast North Atlantic and decrease in the mid-latitudes in the climate change scenario. The dominant North Atlantic storm-track region is estimated to shift northward, especially over the northern Northeast Atlantic, where the frequency of occurrence of the most intense cyclones is estimated to increase. We suggest that changes in storm densities are related to changes in the upper level steering flow in the atmosphere, which are the precursor to changes in the winds and ocean waves.