文章基本信息

标题：Active and passive ocean regimes in a low-order climate model
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作者：Lennaert Van Veen ; Theo Opsteegh ; Ferdinand Verhulst 等
期刊名称：Tellus A: Dynamic Meteorology and Oceanography
电子版ISSN：1600-0870
出版年度：2001
卷号：53
期号：5
页码：599-615
DOI：10.3402/tellusa.v53i5.12229
摘要：A low-order climate model is studied which combines the Lorenz-84 model for the atmosphereon a fast time scale and a box model for the ocean on a slow time scale. In this climate model,the ocean is forced strongly by the atmosphere. The feedback to the atmosphere is weak. Thebehaviour of the model is studied as a function of the feedback parameters. We find regions inparameter space with dominant atmospheric dynamics, i.e., a passive ocean, as well as regionswith an active ocean, where the oceanic feedback is essential for the qualitative dynamics. Theocean is passive if the coupled system is fully chaotic. This is illustrated by comparing theKaplan–Yorke dimension and the correlation dimension of the chaotic attractor to the valuesfound in the uncoupled Lorenz-84 model. The active ocean behaviour occurs at parametervalues between fully chaotic and stable periodic motion. Here, intermittency is observed. Bymeans of bifurcation analysis of periodic orbits, the intermittent behaviour, and the roˆ le playedby the ocean model, is clarified. A comparison of power spectra in the active ocean regime andthe passive ocean regime clearly shows an increase of energy in the low frequency modes of theatmospheric variables. The results are discussed in terms of itinerancy and quasi-stationarystates observed in realistic atmosphere and climate models.