DOI: 10.1175/JCLI-D-14-00761.1
Scopus记录号: 2-s2.0-84945972761
论文题名: Toward the dynamical convergence on the jet stream in aquaplanet AGCMs
作者: Lu J. ; Chen G. ; Leung L.R. ; Burrows D.A. ; Yang Q. ; Sakaguchi K. ; Hagos S.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2015
卷: 28, 期: 17 起始页码: 6763
结束页码: 6782
语种: 英语
Scopus关键词: Advection
; Budget control
; Climate models
; Diffusion
; Liquid waves
; Mixing
; Oceanography
; Peclet number
; Plasma diagnostics
; Troposphere
; Vorticity
; Asymptotic behaviors
; Convergence behaviors
; Eddy-mean flow interaction
; Effective diffusivities
; Eulerian-lagrangian
; Finite amplitude waves
; General circulation model
; Numerical analysis/modeling
; Fighter aircraft
; advection
; atmospheric dynamics
; atmospheric general circulation model
; atmospheric wave
; climate modeling
; jet flow
; jet stream
; mixing
; numerical model
; troposphere
; vorticity
; wave breaking
英文摘要: Systematic sensitivity of the jet position and intensity to horizontal model resolution is identified in several aquaplanet AGCMs, with the coarser resolution producing a more equatorward eddy-driven jet and a stronger upper-tropospheric jet intensity. As the resolution of the models increases to 50 km or finer, the jet position and intensity show signs of convergence within each model group. The mechanism for this convergence behavior is investigated using a hybrid Eulerian-Lagrangian finite-amplitude wave activity budget developed for the upper-tropospheric absolute vorticity. The results suggest that the poleward shift of the eddy-driven jet with higher resolution can be attributed to the smaller effective diffusivity of the model in the midlatitudes that allows more wave activity to survive the dissipation and to reach the subtropical critical latitude for wave breaking. The enhanced subtropical wave breaking and associated irreversible vorticity mixing act to maintain a more poleward peak of the vorticity gradient, and thus a more poleward jet. Being overdissipative, the coarse-resolution AGCMs misrepresent the nuanced nonlinear aspect of the midlatitude eddy-mean flow interaction, giving rise to the equatorward bias of the eddy-driven jet. In accordance with the asymptotic behavior of effective diffusivity of Batchelor turbulence in the large Peclet number limit, the upper-tropospheric effective diffusivity of the aquaplanet AGCMs displays signs of convergence in the midlatitude toward a value of approximately 107 m2 s-1 for the ∇2 diffusion. This provides a dynamical underpinning for the convergence of the jet stream observed in these AGCMs at high resolution. © 2015 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50908
Appears in Collections: 气候变化事实与影响
There are no files associated with this item.
作者单位: Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, United States; Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, United States
Recommended Citation:
Lu J.,Chen G.,Leung L.R.,et al. Toward the dynamical convergence on the jet stream in aquaplanet AGCMs[J]. Journal of Climate,2015-01-01,28(17)