Projected Changes of Wintertime Extra-tropical Storm Activity over North America in the 21st Century

Abstract:

Projected changes of wintertime extra-tropical storm (ETS) activity over the Continental United States and Canada are investigated using GFDL newly developed Seamless System for Prediction and EArth System Research (SPEAR) coupled model. Large ensemble (30-members) high resolution (50km atmos grid) integrated with the SSP585 and Natural scenarios are utilized to investigate how well the ETS activity is stimulated by SPEAR on regional scales, and how it will change in the 21st century. Both objective feature tracking (Lagrangian perspective) and time-filtered variance diagnostic methods are used to measure extra-tropical storm activity. Owing to the large internal variations of ETS activity on interannual and interdecadal time scales, we use the large ensemble simulations to identify the regions which will experience statistically significant radiatively-forced changes in the ETS activity relative to internal variability. The possible impacts on the mean climate and particularly the extremes over the identified regions will be explored.