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.