A comment about the seasonal cycle of precipitation

The gridded fields illustrate the seasonal cycle of Arctic precipitation. During winter, precipitation is highest over the Atlantic sector. This represents the effect of frequent cyclone activity associated with the Icelandic Low. High precipitation totals are also found south of Alaska corresponding to the Aleutian Low. The lowest amounts are found over the central Arctic Ocean and land areas, where cyclone activity is uncommon and anticyclonic conditions are more the rule. From spring into summer, the pattern changes. The precipitation maxima over the Atlantic side and south of Alaska weaken, attended by increases in precipitation over the Arctic Ocean and land. The increases over the Arctic Ocean correspond to the seasonal increase in cyclone activity in this area. This is also true for the increase in precipitation over land. Perhaps surprisingly given the high latitude, the summer maximum in terrestrial precipitation is also contributed to by convective activity (that is, by thunderstorms). Autumn shows the transition back to the winter regime. The maxima associated with the Icelandic and Aleutian lows is reestablished, and precipitation decreases over land.