Winter warming over Dome Fuji, East Antarctica and semiannual oscillation in the atmospheric circulation

Abstract

An abrupt warming was observed in the winter around Dome Fuji (3810 m above sea level (asl)) in East Antarctica. The air temperature increased from −73° C to −36° C in two days, from June 13 to 14, 1994. Warming occurred first in the coastal region near the Lambert Glacier, East Antarctica, then progressed inland to Dome Fuji. During the warming, a blocking high was observed in the middle troposphere and it persisted for several weeks. This circulation pattern brought warm air inland. A blocking high over East Antarctica also appeared in the upper troposphere; this high‐pressure area corresponded to a ridge of stratospheric circulation. This condition occurred after a displacement of the polar vortex from East Antarctica to West Antarctica. Warming at the surface of the ice sheet occurred suddenly; however, in the stratosphere the circulation pattern began to change on a seasonal scale prior to the warming as part of the first phase of the semiannual oscillation.