Understanding Antarctic Peninsula precipitation distribution and variability using a numerical weather prediction model

Abstract

Daily precipitation fields and annual means from the European Centre for Medium-range Weather Forecasts re-analysis exercise are used to examine the distribution and variability of precipitation across the Antarctic Peninsula. The annual mean precipitation field from the model agrees well with the available ice-core data and suggests that the maximum accumulation for the area is on the western side of the barrier at about the 200 m level where the annual total is close to 1.3 m w.e. The Peninsula is shown to be a very effective barrier to the zonal movement of precipitating weather systems, which results in quite different atmospheric flow regimes being responsible for significant precipitation events on either side of the divide. Frontal depressions are the primary source of large daily snowfall totals on both sides of the Peninsula. On the southern coast of the Bellingshausen Sea, major snowfall events are often linked to strong northerly flow when the atmospheric circulation is blocked. Predominantly northerly flow is also responsible for significant snowfall on the Ronne Ice Shelf, which often occurs in association with lee cyclogenesis events to the east of the Peninsula.