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The effect of ocean dynamics and orography on atmospheric storm tracks

Wilson, Christopher; Sinha, Bablu; Williams, Richard, D.. 2009 The effect of ocean dynamics and orography on atmospheric storm tracks. Journal of Climate, 22 (13). 3689-3702. 10.1175/2009JCLI2651.1

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Abstract/Summary

The control of atmospheric storm tracks by ocean dynamics, orography, and their interaction is investigated using idealized experiments with a simplified coupled atmosphere-ocean climate model. The study focuses on the quasi-steady state for the storm tracks in the Northern Hemisphere winter mean. The experiments start with a background state without mountains and ocean dynamics, and in separate stages include orography and a dynamic ocean to obtain a more realistic control simulation. The separate effects of ocean dynamics, orography, and their nonlinear interaction are identified for the storm tracks and the surface thermodynamic forcing over the ocean. The model study suggests that atmospheric storm tracks are a robust feature of the climate system, occurring at midlatitudes even if there is no orographic forcing or ocean heat transport. Ocean dynamics generally lead to a poleward shift in both the storm track and the maximum in atmospheric northward heat transport and induce a northeastward tilt over the Atlantic. This poleward shift is linked to the extra heat transport by the ocean and the tightening of sea surface temperature gradients on the western side of ocean basins. Orographic forcing causes along-track variability with a weakening of the storm track over the continents and induces a northeastward tilt over the western Pacific, which is associated with a stationary planetary wave train generated by the Tibetan Plateau. The interaction between ocean dynamics and orographic forcing plays a localized role, enhancing the contrast between the Atlantic and Pacific. Much of the response to the forcing is eddy mediated and transient eddies help to spread the influence of orographic and ocean forcing.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1175/2009JCLI2651.1
Programmes: Oceans 2025 > Climate, ocean circulation and sea level
ISSN: 0894-8755
Additional Information. Not used in RCUK Gateway to Research.: Copyright (2009) American Meteorological Society (AMS). Permission to use figures, tables,and BRIEF excerpts from this work in scientific and educational works is hereby granted provided that is determined to be "fair use" under section 107 of the US Copyright Act or that it satisfies the conditions specified in 108 of the US Copyright Act (17 USC Section 108 as revised by P.L. 94-553) does not require the AMS's permission. Or in a searchable database, or other uses of this material, except as exempted in the above statement, requires written permissionor a license from the AMS. Additional details are provided in the AMS copyright policy, available on the AMS website located at http://www.ametsoc.org/ or from the AMS at 617-227-2425 or copyright@ametsoc.org
Additional Keywords: CLIMATE SENSITIVITY; HEAT-TRANSPORT; CIRCULATION; MODEL; FLUX
NORA Subject Terms: Marine Sciences
Date made live: 15 Mar 2010 13:42
URI: http://nora.nerc.ac.uk/id/eprint/9482

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