东亚500hpa月平均高度场的切比雪夫系数与南方涛动的耦合振荡关系

ON THE COUPLINGS BETWEEN CHEBYSHEV COEFFICIENTS AS DERIVED FROM THE MONTHLY MEAN GEOPOTENTIAL FIELDS AT 500hPa OVER EAST ASIA AND THE SOUTHERN OSCILLATION

一、引言 气象要素场通常可以通过多种方法,如经验正交函数,切比雪夫正交多项式等,分解成若干典型气象要素场。后者已由规则格点推广到不规则格点。张家诚、陈玉琼等先后探讨了长江中下游降水和温度与东亚500hPa月平均高度场的切比雪夫正交多项式系数(以下简称为切比雪夫系数)的关系,作者也分析了我国西北地区夏季干、湿状况与东亚经向环流指数(A_10)之间的联系。但是,就东亚500hPa月平均高度场切比雪夫系数本身气候振荡的研究仍涉及不多。而这一方面的研究对于加深了解我国大范围的气候异常是有益的。

The first six Chebyshev polynomial coefficients (i. e. , A00, A01, A10, A11, A02, A20) were derived from monthly mean geopotential height over East Asia for the period 1951 - 1983. Spectral analysis of these coefficients revealed relative maxima of power in the frequncy bands of 200 months (-16. 7 years), 25 months (the quasi-biennial oscillation), 5-6 months, and 2 -3 months. Cross- spectal characteristics between chebyshev coefficients and the Southern Oscillation Index (SOI) were also explored. Coherency spectrum for the zonal (A01) and meridional (A10) circulation index with the SOI was significant near 4 years, the QBO, and 2-3 months. Some physical reasons were offered for the spatial linkages (i. e. , teleconnections) between the SO and atmospheric circulation anomalies over East Asia.