Dynamical Circulation Regimes and Temperature Extremes in the Contemporary and 21st Century Arctic

Abstract:

We present updated results of how changing climate affects dynamical circulation regimes, which has implications on the future of Arctic extreme events. We use a fully coupled Regional Arctic System Model (RASM) that includes the Weather Research and Forecasting Model (WRF-ARW), Parallel Ocean Program (POP), Los Alamos Sea Ice Model (CICE5), and Variable Infiltration Capacity (VIC) model coupled with the NCAR CESM CPL7 coupler. RASM simulates a pan-Arctic domain with a 50-km horizontal atmospheric resolution. The simulation uses atmospheric boundary conditions provided by the NCAR CCSM4. Additionally, part of the ocean domain also uses as boundary conditions daily values of SST and SSS from the NCAR CCSM4. Previous results suggest that as sea-ice cover wanes there is a tendency for increased persistent 1-regime (as opposed to 2-regime) behavior in Arctic atmospheric circulation. Using RASM, we extend the analysis to understand the development of persistent dynamical regimes in the 21^st Century. Results from a multi-decadal simulation using RASM will be presented and will focus on the susceptibility of present and future persistent dynamical circulation regimes to producing temperature extremes. Results suggest that identification of when persistent 1- and 2-regime behavior occurs is useful for ascertaining the future of the Arctic temperature extremes.