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A comparative synoptic climatology of cool-season rainfall in major grain-growing regions of southern Australia

Citation

Pook, MJ and Risbey, JS and McIntosh, PC, A comparative synoptic climatology of cool-season rainfall in major grain-growing regions of southern Australia, Theoretical and Applied Climatology, 117, (3-4) pp. 521-533. ISSN 0177-798X (2014) [Refereed Article]

Copyright Statement

Copyright Springer-Verlag Wien 2013

DOI: doi:10.1007/s00704-013-1021-y

Abstract

Two distinct synoptic weather systems, cut-off lows and fronts, deliver most of the cool-season rainfall to the cropping regions of southern Australia. A comparative synoptic climatology of daily rainfall events over approximately five decades reveals both spatial and temporal variations of the dominant synoptic types. The rainfall characteristics and associated large-scale drivers differ between the two synoptic types. Understanding regional rainfall depends on understanding these differences. Cut-off lows contribute one half of growing season rainfall in southeast Australia, while frontal systems associated with Southern Ocean depressions contribute about a third. The proportions are reversed in the Central Wheat Belt (CWB) of Western Australia where Southern Ocean fronts are the dominant source of growing season rainfall. In the southern island state of Tasmania, topography strongly influences the outcome with cut-off lows contributing about half the rainfall near the east coast and fronts dominating a short distance to the west. Cut-off lows generally contribute their highest proportion of rainfall in the austral autumn and spring while frontal rainfall is at its maximum in late winter. Cut-off low rainfall contributes more strongly in percentage terms to the recent decline in rainfall. The distribution of synoptic types is explained by the dominant long-wave structure in the winter half of the year. The major trough near Western Australia favours frontogenesis to the southwest of the CWB but fronts moving out of the region encounter a persistent meridional ridge in the Tasman Sea where there is a high frequency of blocking events.

Item Details

Item Type:Refereed Article
Keywords:climatology, comparative study, frontogenesis, oceanic front, rainfall, spatial variation, synoptic meteorology, temporal variation, topography, trough
Research Division:Earth Sciences
Research Group:Atmospheric Sciences
Research Field:Climatology (excl. Climate Change Processes)
Objective Division:Environment
Objective Group:Atmosphere and Weather
Objective Field:Atmospheric Processes and Dynamics
Author:McIntosh, PC (Dr Peter McIntosh)
ID Code:119502
Year Published:2014
Web of Science® Times Cited:6
Deposited By:Centre for Ecology and Biodiversity
Deposited On:2017-08-02
Last Modified:2017-10-16
Downloads:0

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