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The synoptic climatology of cool-season rainfall in the central wheatbelt of Western Australia

Citation

Pook, MJ and Risby, JS and McIntosh, PC, The synoptic climatology of cool-season rainfall in the central wheatbelt of Western Australia, Monthly Weather Review, 140, (1) pp. 28-43. ISSN 0027-0644 (2012) [Refereed Article]


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DOI: doi:10.1175/MWR-D-11-00048.1

Abstract

Synoptic weather systems form an important part of the physical link between remote large-scale climate drivers and regional rainfall. A synoptic climatology of daily rainfall events is developed for the Central Wheatbelt of southwestern Australia over the April–October growing season for the years 1965–2009. The climatology reveals that frontal systems contribute approximately one-half of the rainfall in the growing season while cutoff lows contribute about a third. The ratio of frontal rainfall to cutoff rainfall varies throughout the growing season. Cutoff lows contribute over 40% of rainfall in the austral autumn and spring, but this falls to about 20% in August when frontal rainfall climbs to more than 60%. The number of cutoff lows varies markedly from one growing season to another, but does not exhibit a significant long-term trend. The mean rainfall per cutoff system is also highly variable, but has gradually declined over the analysis period, particularly in the past decade. The decline in rainfall per frontal system is less significant. Cutoff low rainfall has contributed more strongly in percentage terms to the recent decline in rainfall in the Central Wheatbelt than the frontal component and accounts for more than half of the overall trend. Atmospheric blocking is highly correlated with rainfall in the region where cutoff low rainfall makes its highest proportional contribution. Hence, the decline in rain from cutoff low systems is likely to have been associated with changes in blocking and the factors controlling blocking in the region.

Item Details

Item Type:Refereed Article
Keywords:Australia, climate variability, climatology, cutoff lows, fronts
Research Division:Earth Sciences
Research Group:Atmospheric Sciences
Research Field:Meteorology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Environmental Sciences
Author:Pook, MJ (Dr Michael Pook)
Author:McIntosh, PC (Dr Peter McIntosh)
ID Code:119087
Year Published:2012
Web of Science® Times Cited:21
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2017-07-26
Last Modified:2017-08-03
Downloads:23 View Download Statistics

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