North Atlantic cloud cover response to the North Atlantic oscillation and relationship to surface temperature changes

[1] Cloud cover changes over the high-latitude North Atlantic during January associated with the North Atlantic oscillation (NAO) are studied using the Polar MM5 regional climate model. The cloud response to the NAO is marked by an increase in cloudiness during the high phase over much of the North Atlantic east of Greenland and an overall decrease in cloudiness west of Greenland. These cloud changes are accompanied by surface cloud radiative forcing anomalies that are of the same sign as the model-simulated surface air temperature (SAT) anomalies in most areas. NAO-related cloud cover changes in January are therefore likely to represent a positive feedback on the SAT changes induced by anomalous atmospheric advection.