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contributor authorSaravanan, R.
contributor authorMcWilliams, James C.
date accessioned2017-06-09T15:37:54Z
date available2017-06-09T15:37:54Z
date copyright1998/02/01
date issued1998
identifier issn0894-8755
identifier otherams-4916.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4188578
description abstractAtmospheric variability on timescales of a month or longer is dominated by a small number of large-scale spatial patterns (?teleconnections?), whose time evolution has a significant stochastic component because of weather excitation. One may expect these patterns to play an important role in ocean?atmosphere interaction. On interannual and longer timescales, horizontal advection in the ocean can also play an important role in such interaction. The authors develop a simple one-dimensional stochastic model of the interaction between spatially coherent atmospheric forcing patterns and an advective ocean. The model may be considered a generalization of the zero-dimensional stochastic climate model proposed by Hasselmann. The model equations are simple enough that they can be solved analytically, allowing one to fully explore the parameter space. The authors find that the solutions fall into two regimes: (i) a slow?shallow regime where local damping effects dominate and (ii) a fast?deep regime where nonlocal advective effects dominate. An interesting feature of the fast?deep regime is that the ocean?atmosphere system shows preferred timescales, although there is no underlying oscillatory mechanism in the uncoupled ocean or in the uncoupled atmosphere. Furthermore, the existence of the preferred timescale in the ocean does not depend upon a strong atmospheric response to SST anomalies. The timescale is determined by the advective velocity scale associated with the upper ocean and the length scale associated with low-frequency atmospheric variability. For the extratropical North Atlantic basin, this timescale would be of the order of a decade, indicating that advective ocean?atmosphere interaction could play an important role in decadal climate variability. The solutions also highlight the differences between local thermodynamic feedbacks associated with changes in the air?sea temperature difference and nonlocal dynamic feedbacks associated with horizontal ocean advection.
publisherAmerican Meteorological Society
titleAdvective Ocean–Atmosphere Interaction: An Analytical Stochastic Model with Implications for Decadal Variability
typeJournal Paper
journal volume11
journal issue2
journal titleJournal of Climate
identifier doi10.1175/1520-0442(1998)011<0165:AOAIAA>2.0.CO;2
journal fristpage165
journal lastpage188
treeJournal of Climate:;1998:;volume( 011 ):;issue: 002
contenttypeFulltext


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