Fig. 9: Illustration of the link between North American snow cover and atmospheric circulation over Greenland.

Low spring snow cover causes early depletion of soil moisture over eastern North America (brown shading). The dry conditions that follow produce a warm surface anomaly that persists into July (orange shading). This anomalous heating of the near-surface atmosphere induces a stationary Rossby wave response that propagates northeastward (yellow arrow) and favors high-pressure ridging over Greenland—conditions which are known to augment melt of the Greenland Ice Sheet (blue shading). Red H denotes high pressure; blue L denotes low pressure.