DOI: 10.1007/s00382-011-1016-2
Scopus记录号: 2-s2.0-84855277759
论文题名: Severe heat waves in Southern Australia: Synoptic climatology and large scale connections
作者: Pezza A.B. ; van Rensch P. ; Cai W.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2012
卷: 38, 期: 2017-01-02 起始页码: 209
结束页码: 224
语种: 英语
英文关键词: Anticyclones
; Climate variability
; Cold waves
; Cyclones
; Heat waves
英文摘要: This paper brings a new perspective on the large scale dynamics of severe heat wave (HW) events that commonly affect southern Australia. Through an automatic tracking scheme, the cyclones and anticyclones associated with HWs affecting Melbourne, Adelaide and Perth are tracked at both the surface and upper levels, producing for the first time a synoptic climatology that reveals the broader connections associated with these extreme phenomena. The results show that a couplet (or pressure dipole) formed by transient cyclones and anticyclones can reinforce the HW similarly to what is observed in cold surges (CS), with an obvious opposite polarity. Our results show that there is a large degree of mobility in the synoptic signature associated with the passage of the upper level ridges before they reach Australia and the blocking is established, with HW-associated surface anticyclones often initiating over the west Indian Ocean and decaying in the eastern Pacific. In contrast to this result the 500 hPa anticyclone tracks show a very small degree of mobility, responding to the dominance of the upper level blocking ridge. An important feature of HWs is that most of the cyclones are formed inland in association with heat troughs, while in CS the cyclones are typically maritime (often explosive), associated with a strong cold front. Hence the influence of the cyclone is indirect, contributing to reinforce the blocking ridge through hot and dry advection on the ridge's western flank. Additional insights are drawn for the record Adelaide case of March 2008 with fifteen consecutive days above 35°C breaking the previous record by 7 days. Sea surface temperatures suggest a significant air-sea interaction mechanism, with a broad increase in the meridional temperature gradient over the Indian Ocean amplifying the upstream Rossby waves that can trigger HW events. A robust cooling of the waters close to the Australian coast also contributes to the maintenance of the blocking highs locally, which is a fundamental ingredient to sustain the HWs. © 2011 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/55398
Appears in Collections: 过去全球变化的重建
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作者单位: School of Earth Sciences, The University of Melbourne, Melbourne, VIC 3010, Australia; CSIRO Marine and Atmospheric Research, Aspendale, VIC 3195, Australia
Recommended Citation:
Pezza A.B.,van Rensch P.,Cai W.. Severe heat waves in Southern Australia: Synoptic climatology and large scale connections[J]. Climate Dynamics,2012-01-01,38(2017-01-02)