On the impacts of climate change and the upper ocean on midlatitude northwest Atlantic landfalling cyclones

Abstract

The influence of climate change on midlatitude North Atlantic landfalling autumn storms is investigated using a relatively high-resolution mesoscale atmosphere-ocean coupled model system. Atmospheric boundary conditions for autumn storm simulations by this coupled model system are given by the Canadian second-generation Coupled Global Climate Model (CGCM2), following the Intergovernmental Panel on Climate Change IS92a scenario. The control and high-CO 2 boundary conditions are obtained from CGCM2 simulations representing the present climate (1975-1994), and a future climate change scenario (2040-2059), corresponding to a doubling of greenhouse gases. An understanding of the possible influences of climate change on the storm climate is achieved through our simulations. The impact of climate change is seen in slightly decreased intensities in landfalling cyclones (about 5 hPa) resulting from the competition between warming provided by the climate change scenario and modest cooling around the storm center induced mainly by dynamic cooling. An additional impact is that cyclone tracks tend to shift poleward. Copyright 2010 by the American Geophysical Union.