2005年北半球大气环流特征及其对中国气候异常的影响

General Circulation over the Northern Hemisphere in 2005 and Its Impact on the Climate in China

2005年北半球主要环流特征为,500hPa西太平洋副热带高压较常年明显偏强,位置总体偏西偏北,春季副高位置异常偏西;东亚地区夏季500hPa位势高度距平场上大部地区为正距平分布,贝加尔湖南部为正距平中心。亚洲中纬度经、纬向环流交替出现,冬季经向环流异常发展,造成我国东部地区气温异常偏低;夏季纬向环流发展,同时东亚夏季风偏强,汛期主要雨带位置位于淮河流域。冬、春季热带对流活动减弱,入夏以后迅速加强,台风活动活跃。热带海洋为暖水位相。在海洋和大气环流的共同影响下我国天气气候发生了明显异常。

General circulation features over the Northern Hemisphere in 2005 are analyzed. It is shown that the 500hPa subtropical high over the West Pacific is stronger than normal. Its position is westerly and northerly as a whole. Its ridge point is abnormal to the west in spring. At 500hPa, zonal and meridional circulations take place by turn, cold air is stronger than normal during the winter. Monsoon is stronger during the summer, convection activity is weaker during the winter and the spring, and into the summer is stronger in tropics. A warm water process is persisting in the tropical Pacific region in 2005. The anomaly of both the tropical Pacific and atmospheric circulation exerted a significant impact on the weather and climate in China.