冬季亚澳季风环流的低频耦合过程

利用1982—1983年和1984—1985年两个冬季的欧洲中期预报中心格点资料研究了冬季东亚西风急流与澳大利亚夏季风在低频尺度上的相互作用与可能的传播方式。结果表明,我国北部上空的西风急流(及相应的锋区)与澳大利亚的夏季风的低频变化有很好的一致性。它们的联系和相互作用表现为:东亚西风急流通过改变西北太平洋地区的越赤道气流影响澳大利亚夏季风的低频变化,而澳大利亚夏季风则通过增强或减弱的高空辐散向北气流影响东亚西风急流。将这种相互作用称为亚澳季风环流的“低频耦合过程”。

LOW-FREQUENCY COUPLING PROCESSES BETWEEN ASIAN AND AUSTRALIAN MONSOON CIRCULATIONS IN THE NORTHERN WINTER

Based on the 1982-1983 and 1984-1985 winter grid data of the ECMWF, low-frequency interactions between the westerly jet of East Asia and Australian summer monsoon and their possible propagation modes are investigated in this paper. The results show that there is a good consistency between the low-frequency variations of the westerly jet (and its relevant front zone) over the Northern China and Australian summer monsoon. The expression of their links, and interactions are shown by the fact that East Asian westerly jet affects the low-frequency variations of Australian summer monsoon through changing the cross-equatorial flows over the Northern West Pacific; Australian summer monsoon influences East Asian westerly jet by strengthening and weakening the upper-level northward divergent flows. We call those interactions as the "low-frequency coupling processes" of Asian and Australian monsoon circulations.