应用自然正交函数表示极区高度场特征的尝试

应用自然正交函数，根据12个月多年平均的极区高度场资料求得了一组有明显天气学意义的特征向量。每一个特征向量代表一种高度场的典型分布。将具体某年某月的实际高度场在这组特征向量上的投影定义为极涡系数。每一个极涡系数就表示实际高度场与相应典型场的相似程度。极涡系数与我国长期天气变化有着密切的关系。

An Attempt of Representing the Features of Height Field in Polar Area by Using Experimental Orthogonal Function

By using monthly mean values of geopotential height field in 12 months in the polar region and the empirical orthogonal function we obtained a set of eigenvectors having a clear synoptic significance, every eigenvector represents a typical distribution of height field. We define the projections of monthly mean height fields for individual years on these eigenvectors as polar vortex coefficients. The polar vortex coefficients represent the degree of resemblance of real height fields to the corresponding tropical fields. It is found that the polar vortex coefficients have a close relation to the weather of out country.