Relationship between stratospheric circulation anomalies and extended snow storm

In order to investigate the relationship between the stratospheric circulation anomaly and the exceptionally serious snow storms which occurred in the southern part of China in 2008, the variation of the atmospheric circulation in the stratosphere from October, 2007 to February, 2008 was analyzed using NCEP data. The results show that before the occurrence of the snow storms the stratospheric north polar vortex abnormally strengthened and deformed, and the stratospheric circulation in the middle-lower latitudes changed significantly. These anomalies propagated downward and affected the troposphere. This means that the snow storms were connected not only with the changes of the tropospheric circulation, but also with the changes of the stratospheric circulation. Meaningfully, the changes of the stratospheric circulation were more than a month ahead of the snow storms. Therefore information of the stratospheric circulation is very conducive to improving the middle and long term weather forecast, especially the forecast of serious meteorological calamities.