The influence of snow cover on Northern Hemisphere climate variability

The importance of snow cover anomalies on the local energy balance is well known, however, the potential impact of snow cover anomalies on local and remote atmospheric dynamics is less understood. We present observational evidence demonstrating a statistically significant relationship between seasonal snow cover and winter-time circulation anomalies over mid-high latitudes. To explore snow forcing further, a General Circulation Model is used to test whether the local diabatic changes caused by snow cover can induce large-scale dynamical responses. A six-member ensemble, three winter month (DJF) integration is performed for a control case and a case where snow cover is increased as observed during the positive-anomalous winter of 1977/1978. Snow cover variability results in altered general circulation patterns resembling observed anomaly patterns at mid-high latitudes in the Northern Hemisphere winter.