1961—2017年南极冰盖近地面风时空变化研究

Spatial and temporal variations of the near-surface winds over the Antarctic Ice Sheet during 1961—2017

基于19个人工气象站1961—2017年风速风向实测数据对南极冰盖近地面风速时空变化和风向进行了分析。结果表明:近50年来,南极冰盖近地面各季节平均风速和年平均风速变化的空间模式基本一致。东南极0°~120°E沿海地区风速呈显著上升趋势;南极半岛气象站风速变化趋势各异,且变化速率相差甚大,但从区域平均结果来看,南极半岛年和季节平均风速均呈上升趋势。这与近几十来局地气温、气压变化及南半球环状模趋向于正位相发展有关。东南极受下降风和绕极东风影响,大部分地区盛行偏南风或偏东风,且频率较高风向稳定;而受天气活动影响,南极半岛风向复杂,主风向频率低,风向多变。

Based on the measured wind speed and wind direction data from 19 manned weather stations during 1961—2017,the temporal and spatial variations of near-surface wind speed and wind direction over the Antarc⁃tic ice sheet were analyzed.The results show similar spatial variability patterns between seasonal and annual mean near-surface wind speeds over the Antarctic Ice Sheet from 1961 to 2017.The wind speeds in the coastal area of 0°~120°E sector of East Antarctica showed a significant upward trend.The sign and magnitude of trends in the wind speeds from 6 meteorological stations on the Antarctic Peninsula are different.Both annual and sea⁃sonal wind speeds averaged over the 6 stations exhibited upward trends during 1961—2017.The upward trends were related to local warming,decline in the sea level pressure,and the positive polarity of the southern annular mode in recent decades.Southerly or easterly winds prevailed in most areas of East Antarctica,and the wind di⁃rections were stable.On the Antarctic Peninsula,influenced by frequently synoptic activities,the wind direc⁃tions are variable,and it is not easy to determine the dominant wind direction.