Abrupt changes in meteorological conditions observed at an inland Antarctic station in association with wintertime blocking

摘要

Time evolution of a prominent wintertime blocking event over East Antarctica and the associated drastic changes in weather conditions observed at an inland station are documented. A strong blocking ridge was formed at the leading edge of a quasi-stationary Rossby wavetrain where a wave activity flux emanating from the subtropics was convergent. The ridge pumped up heat and moisture from lower latitudes into inland Antarctica with a strong poleward flow along its upstream flank. The station was situated under this flow just for two days, during which the normal condition with cold and clear weather was markedly disturbed. The flow climbing up the continental slope led to cloud formation above the inland station. Enhanced downward longwave radiation from the clouds and enhanced vertical mixing associated with the record-setting wind speeds resulted in a sudden, drastic increase in surface air temperature and the breakdown of the developed surface inversion layer. [References: 24]