DOI: 10.1007/s00382-015-2786-8
Scopus记录号: 2-s2.0-84939241392
论文题名: On the dynamics of persistent states and their secular trends in the waveguides of the Southern Hemisphere troposphere
作者: O’Kane T.J. ; Risbey J.S. ; Monselesan D.P. ; Horenko I. ; Franzke C.L.E.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 46, 期: 2017-11-12 起始页码: 3567
结束页码: 3597
语种: 英语
英文关键词: Atmospheric teleconnections
; Baroclinic instability
; Regimes
; Rossby waves
; Secular trends
; Waveguides
英文摘要: We identify the dynamical drivers of systematic changes in persistent quasi-stationary states (regimes) of the Southern Hemisphere troposphere and their secular trends. We apply a purely data-driven approach, whereby a multiscale approximation to nonstationary dynamical processes is achieved through optimal sequences of locally stationary fast vector autoregressive factor processes, to examine a high resolution atmospheric reanalysis over the period encompassing 1958–2013. This approach identifies regimes and their secular trends in terms of the predictability of the flow and is Granger causal. A comprehensive set of diagnostics on both isentropic and isobaric surfaces is employed to examine teleconnections over the full hemisphere and for a set of regional domains. Composite states for the hemisphere obtained from nonstationary nonparametric cluster analysis reveal patterns consistent with a circumglobal wave 3 (polar)–wave 5 (subtropical) pattern, while regional composites reveal the Pacific South American pattern and blocking modes. The respective roles of potential vorticity sources, stationary Rossby waves and baroclinic instability on the dynamics of these circulation modes are shown to be reflected by the seasonal variations of the waveguides, where Rossby wave sources and baroclinic disturbances are largely contained within the waveguides and with little direct evidence of sustained remote tropical influences on persistent synoptic features. Warm surface temperature anomalies are strongly connected with regions of upper level divergence and anticyclonic Rossby wave sources. The persistent states identified reveal significant variability on interannual to decadal time scales with large secular trends identified in all sectors apart from a region close to South America. © 2015, Springer-Verlag Berlin Heidelberg.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53703
Appears in Collections: 过去全球变化的重建
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作者单位: CSIRO Oceans and Atmosphere, Hobart, Australia; Universita della Svizzera, Italiana, Lugano, Switzerland; Meteorological Institute and Center for Earth System Research and Sustainability, University of Hamburg, Hamburg, Germany
Recommended Citation:
O’Kane T.J.,Risbey J.S.,Monselesan D.P.,et al. On the dynamics of persistent states and their secular trends in the waveguides of the Southern Hemisphere troposphere[J]. Climate Dynamics,2016-01-01,46(2017-11-12)