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A regional response in mean westerly circulation and rainfall to projected climate warming over Tasmania, Australia


Grose, MR and Corney, SP and Katzfey, JJ and Bennett, JC and Holz, GK and White, CJ and Bindoff, NL, A regional response in mean westerly circulation and rainfall to projected climate warming over Tasmania, Australia, Climate Dynamics, 40, (7-8) pp. 2035-2048. ISSN 0930-7575 (2012) [Refereed Article]

Copyright Statement

Copyright Springer-Verlag 2012

DOI: doi:10.1007/s00382-012-1405-1


Coupled ocean–atmosphere general circulation models (GCMs) lack sufficient resolution to model the regional detail of changes to mean circulation and rainfall with projected climate warming. In this paper, changes in mean circulation and rainfall in GCMs are compared to those in a variable resolution regional climate model, the Conformal Cubic Atmospheric Model (CCAM), under a high greenhouse gas emissions scenario. The study site is Tasmania, Australia, which is positioned within the mid-latitude westerlies of the southern hemisphere. CCAM projects a different response in mean sea level pressure and mid-latitude westerly circulation to climate warming to the GCMs used as input, and shows greater regional detail of the boundaries between regions of increasing and decreasing rainfall. Changes in mean circulation dominate the mean rainfall response in western Tasmania, whereas changes to rainfall in the East Coast are less related to mean circulation changes. CCAM projects an amplification of the dominant westerly circulation over Tasmania and this amplifies the seasonal cycle of wet winters and dry summers in the west. There is a larger change in the strength than in the incidence of westerly circulation and rainfall events. We propose the regional climate model displays a more sensitive atmospheric response to the different rates of warming of land and sea than the GCMs as input. The regional variation in these results highlight the need for dynamical downscaling of coupled general circulation models to finely resolve the influence of mean circulation and boundaries between regions of projected increases and decreases in rainfall.

Item Details

Item Type:Refereed Article
Keywords:climate change, mean circulation, regional climate model
Research Division:Earth Sciences
Research Group:Climate change science
Research Field:Climate change processes
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Climate change models
UTAS Author:Grose, MR (Dr Michael Grose)
UTAS Author:Corney, SP (Dr Stuart Corney)
UTAS Author:Holz, GK (Dr Greg Holz)
UTAS Author:White, CJ (Dr Chris White)
UTAS Author:Bindoff, NL (Professor Nathan Bindoff)
ID Code:80531
Year Published:2012
Web of Science® Times Cited:19
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2012-11-02
Last Modified:2017-10-30

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