Representation of Arctic moist intrusions in global coupled climate models

Events with warm and moist air entering the Arctic have been shown to have a substantial effect on the surface temperature climate in winter. Here, the coupled global climate models participating in the Coupled Model Intercomparison project Phase 5 (CMIP5) are evaluated with respect to these events. The results show that the models systematically underpredict the moisture flux in the Atlantic sector and overpredict it in the Pacific sector.The biases are predominantly due to misrepresentation of extreme moisture flux events that have been shown to have the most influence on the Arctic surface climate.

Figure: Mean bias of climatological intrusion trajectory density during DJF 1981 – 2005 in CMIP5 models compared to ERA-Interim reanalysis. The darkest blue and red colors are  < -2 and > 2 in number density, respectively.

Woods, C., R. Caballero, and G. Svensson, 2017: Representation of Arctic Moist Intrusions in CMIP5 Models and Implications for Winter Climate Biases. J. Climate, 30, 4083–4102, https://doi.org/10.1175/JCLI-D-16-0710.1