Journal of Climate 2013 ; e-View
A multi-model assessment of future projections of North Atlantic and European extratropical cyclones in the CMIP5 climate models
National Centre for Atmospheric Science, Department of Meteorology, University of Reading, Reading, UKLen C. Shaffrey
National Centre for Atmospheric Science, Department of Meteorology, University of Reading, Reading, UKKevin I. HodgesPhil G. SansomDavid B. Stephenson
The response of North Atlantic and European extratropical cyclones to climate change is investigated in the climate models participating in CMIP5 (Fifth Coupled Model Intercomparison Project). In contrast to previous multi–model studies, a feature tracking algorithm is here applied to separately quantify the responses in both the number, the wind intensity and the precipitation intensity of extratropical cyclones. Moreover, a statistical framework is employed to formally assess the uncertainties in the multi–model projections. Under the mid range RCP4.5 emission scenario, the DJF response is characterised by a tripolar pattern over Europe, with an increase in the number of cyclones in central Europe and a decreased number in the Norwegian sea and in the Mediterranean. The JJA response is characterised by a reduction in the number of North Atlantic cyclones along the southern flank of the stormtrack. The total number of cyclones decreases in both DJF (-4%) and JJA (-2%). By classifying cyclones according to their intensity, we find that there is a slight basin–wide reduction in the number of cyclones associated with strong winds, but an increase in those associated with strong precipitation. However, in DJF, a slight increase in the number and intensity of cyclones associated with strong wind speeds is found over the UK and central Europe. The results are confirmed under the high emission RCP8.5 scenario, where the signals tend to be larger. The sources of uncertainty in these projections are discussed.