气候变化领域集成服务门户(CCPortal): Cut-off lows in the Southern Hemisphere and their extension to the surface

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DOI	10.1007/s00382-021-05662-7
	Cut-off lows in the Southern Hemisphere and their extension to the surface
	Barnes M.A.; Ndarana T.; Landman W.A.
发表日期	2021
ISSN	0930-7575
起始页码	1317
结束页码	1334
卷号	56 期号:2021-11-12
英文摘要	Many cut-off low (COL) climatologies have been done throughout the Southern Hemisphere. Few have focused on COL vertical depth and their link to surface cyclones that often accompany these systems. Here we extend these climatologies in order to gain an understanding of the spatial, mobility, temporal, and seasonal variability of COL extensions towards the surface. Deep COLs (dCOLs), with extension all the way to the surface, are most frequent in the autumn months, are longer lasting, are more mobile and found most frequently situated in the high latitudes. They are usually collocated with Rossby wave breaking (RWB) on multiple isentropic surfaces. These RWB events drive high potential vorticity air into the upper troposphere. The depths of these intrusions are also shown to be critical to the development of COL extensions with dCOLs associated with deeper intrusions into the mid-troposphere. Upper-level PV features are collocated with warm surface potential temperature anomalies which can play a critical role in surface cyclogenesis. The warm surface potential temperature features, when out of phase with coupled upper tropospheric processes (surface features lagging behind upper level processes), can inhibit surfaceward extension and result in shallow COL (sCOL) development. Composite analysis shows that dCOLs that drive their own surface low development result in the simultaneous amplification of troughs throughout the troposphere, with the surface cyclone developing within a day of the COL. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
英文关键词	Cut-off low extensions; Potential vorticity; Rossby wave breaking; Stratospheric intrusions; Surface cyclogenesis
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/183255
作者单位	Marine Research Unit, South African Weather Service, Cape Town, South Africa; Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africa
推荐引用方式 GB/T 7714	Barnes M.A.,Ndarana T.,Landman W.A.. Cut-off lows in the Southern Hemisphere and their extension to the surface[J],2021,56(2021-11-12).
APA	Barnes M.A.,Ndarana T.,&Landman W.A..(2021).Cut-off lows in the Southern Hemisphere and their extension to the surface.Climate Dynamics,56(2021-11-12).
MLA	Barnes M.A.,et al."Cut-off lows in the Southern Hemisphere and their extension to the surface".Climate Dynamics 56.2021-11-12(2021).