2001年北半球大气环流特征及其对中国气候异常的影响

2001年受前期赤道东太平洋海温长期冷水位相的影响,北半球大气环流的主要特征表现为：500hPa西太平洋副热带高压冬春季偏强,夏季秋偏弱;欧亚地区夏季500hPa位势高度距平场上中高纬从西到东呈现为“－＋－”分布形式,贝加尔湖地区为正距平中心;东亚冬、夏季风偏弱;7月赤道辐合带异常偏强、偏北等。在上述大气环流的影响下,我国的天气气候发生了异常。

General Circulation over the Northern Hemisphere in 2001 and Its Impact on the Climate in China

General circulation features over the Northern Hemisphere in 2001 are analyzed. It's shown that the subtropical high at 500hPa over the western Pacific in the winter of 2000/2001 and the spring of 2001 was stronger than normal, and was weaker in the summer and the autumn. In the summer of 2001, the 500hPa geopotential height anomaly was positive in the Eurasia, and the positive center was over Lake Baikal. Both in the winter and the summer, the East Asian monsoon was weaker than normal. In the July of 2001, the equatorial convergence zone was more active than normal, and its position was more north than normal. The SSTa in the eastern tropical Pacific was negative in 2001. The results show that the anomalies of both the sea temperature the tropical Pacific and atmosphere circulation would exert a significant impact on the weather and climate in China.