北极海冰对2008年1月乌拉尔高压异常的影响

2008年1月我国南方发生了大范围的雨雪冰冻灾害天气,造成此次灾害的一个重要原因是乌拉尔高压异常的长期维持,而作为下垫面的海洋,2007/2008冬季环北欧海海冰异常偏少。观测资料合成分析表明,乌拉尔山地区出现高压异常与巴伦支海和喀拉海的海冰偏少存在密切对应关系。利用大气环流模式试验研究了(90°W~60°E)区域海冰异常对大气的影响,模拟结果显示海冰对乌拉尔高压异常有正的贡献,线性模式诊断表明天气尺度瞬变波是海冰影响乌拉尔高压异常的一种重要机制。

Impact of Arctic Sea Ice on the High Pressure over the Ural Mountains during January 2008

The most severe snowstorm and freezing rain event struck southern China in January 2008. One of the main reasons for the disaster was the occurrence of atmospheric circulation anomalies over middle and high latitudes, in particular, a persistent high pressure anomaly over the Ural Mountains. As the boundary layer, the Arctic sea ice near northern Europe decreased during the winter of 2007/2008. Composite analyses indicate that the positive height anomaly over the Ural Mountains is closely related to the decreased Arctic sea ice near northern Europe in January. The role of the sea ice anomaly (90°W-60°E) was investigated using atmospheric model experiments; the sea ice anomaly was found to favor high pressure over the Ural Mountains, and transient eddy forcing was one important mechanism by which the sea ice concentration anomalies influenced the atmospheric circulation anomalies.