DOI: 10.1175/JCLI-D-12-00348.1
Scopus记录号: 2-s2.0-84878959657
论文题名: Southern annular mode dynamics in observations and models. Part I: The influence of climatological zonal wind biases in a comprehensive GCM
作者: Simpson I.R. ; Hitchcock P. ; Shepherd T.G. ; Scinocca J.F.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2013
卷: 26, 期: 11 起始页码: 3953
结束页码: 3967
语种: 英语
Scopus关键词: Climatological circulation
; Correcting procedure
; Global climate model
; Middle atmosphere model
; Southern Annular Mode
; Southern Hemisphere
; Stratospheric variability
; Stratospheric vortex
; Climate models
; Troposphere
; Upper atmosphere
; accuracy assessment
; climate modeling
; climatology
; error analysis
; future prospect
; observational method
; prediction
; sampling bias
; Southern Hemisphere
; stratosphere
; summer
; troposphere
; vortex flow
; weather forecasting
; zonal wind
英文摘要: A common bias among global climate models (GCMs) is that they exhibit tropospheric southern annular mode (SAM) variability that is much too persistent in the Southern Hemisphere (SH) summertime. This is of concern for the ability to accurately predict future SH circulation changes, so it is important that it be understood and alleviated. In this two-part study, specifically targeted experiments with the Canadian Middle Atmosphere Model (CMAM) are used to improve understanding of the enhanced summertime SAM persistence. Given the ubiquity of this bias among comprehensive GCMs, it is likelythat the results will be relevant for other climate models. Here, in Part I, the influence of climatological circulation biases on SAM variability is assessed, with a particular focus on two common biases that could enhance summertime SAM persistence: the too-late breakdown of the Antarctic stratospheric vortex and the equatorward bias in the SH troposphericmidlatitude jet. Four simulations are used to investigate the role of each of these biases in CMAM. Nudging and bias correcting procedures are used to systematically remove zonal-mean stratospheric variability and/or remove climatological zonal wind biases. The SAM time-scale bias is not alleviated by improving either the timing of the stratospheric vortex breakdown or the climatological jet structure. Even in the absence of stratospheric variability and with an improved climatological circulation, the model time scales are biased long. This points toward a bias in internal tropospheric dynamics that is not caused by the tropospheric jet structure bias. The underlying cause of this is examined in more detail in Part II of this study. ©2013 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/51846
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Physics, University of Toronto, Toronto, ON, Canada; Department of Physics, University of Toronto, Canada; Department of Meteorology, University of Reading, Reading, United Kingdom; Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, BC, Canada; Department of Ocean and Climate Physics, Lamont Doherty Earth Observatory, Columbia University, Palisades, NY 10964-1000, United States; Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom
Recommended Citation:
Simpson I.R.,Hitchcock P.,Shepherd T.G.,et al. Southern annular mode dynamics in observations and models. Part I: The influence of climatological zonal wind biases in a comprehensive GCM[J]. Journal of Climate,2013-01-01,26(11)