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contributor authorLatif, M.
contributor authorSterl, A.
contributor authorMaier-Reimer, E.
contributor authorJunge, M. M.
date accessioned2017-06-09T15:17:27Z
date available2017-06-09T15:17:27Z
date copyright1993/01/01
date issued1993
identifier issn0894-8755
identifier otherams-3957.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4177922
description abstractA 26-year integration has been performed with a coupled ocean-atmosphere general circulation model (CGCM). The oceanic part resolves all three oceans in the latitude band 70°N?70°S but is dynamically active only between 30°N and 30°S. The atmosphere is represented by a global low-order spectral model. The coupled model was forced by seasonally varying insolation. Although the simulated time-averaged mean conditions in both atmosphere and ocean show significant deviations from the observed climatology, the CGCM realistically simulates the interannual variability in the tropical Pacific. In particular, the CGCM simulates an irregular ENSO with a preferred time scale of about 3 years. The mechanism for the simulated interannual variability in the tropical Pacific is related to both the ?delayed action oscillator? and the ?slow SST mode.? It therefore appears likely that either both modes can coexist or they degenerate to one mode within certain locations of the parameter space. This hypothesis is also supported by calculations performed with simplified coupled models, in which the atmospheric GCM was replaced by linear steady-state atmosphere models. Further, evidence is found for an eastward migration of zonal wind anomalies over the western Pacific prior to the extremes of the simulated ENSO, indicating a link to circulation systems over Asia. Because an earlier version of the CGCM did not simulate interannual variability in the tropical Pacific, additional experiments with a simplified coupled model have been conducted to study the sensitivity of coupled systems to varying mean oceanic background conditions. It is shown that even modest changes in the background conditions can push the coupled system from one flow regime into another.
publisherAmerican Meteorological Society
titleClimate Variability in a Coupled GCM. Part I: The Tropical Pacific
typeJournal Paper
journal volume6
journal issue1
journal titleJournal of Climate
identifier doi10.1175/1520-0442(1993)006<0005:CVIACG>2.0.CO;2
journal fristpage5
journal lastpage21
treeJournal of Climate:;1993:;volume( 006 ):;issue: 001
contenttypeFulltext


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