DOI: 10.1073/pnas.1916272117
论文题名: The vortex gas scaling regime of baroclinic turbulence
作者: Gallet B. ; Ferrari R.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2020
卷: 117, 期: 9 起始页码: 4491
结束页码: 4497
语种: 英语
英文关键词: Atmospheric dynamics
; Oceanography
; Turbulence
Scopus关键词: advection
; Article
; atmosphere
; atmospheric transport
; baroclinic turbulence
; eddy diffusivity
; flow kinetics
; mathematical analysis
; ocean current
; priority journal
; sea
; temperature
; vortex gas
; vortex motion
英文摘要: The mean state of the atmosphere and ocean is set through a balance between external forcing (radiation, winds, heat and freshwater fluxes) and the emergent turbulence, which transfers energy to dissipative structures. The forcing gives rise to jets in the atmosphere and currents in the ocean, which spontaneously develop turbulent eddies through the baroclinic instability. A critical step in the development of a theory of climate is to properly include the eddy-induced turbulent transport of properties like heat, moisture, and carbon. In the linear stages, baroclinic instability generates flow structures at the Rossby deformation radius, a length scale of order 1,000 km in the atmosphere and 100 km in the ocean, smaller than the planetary scale and the typical extent of ocean basins, respectively. There is, therefore, a separation of scales between the large-scale gradient of properties like temperature and the smaller eddies that advect it randomly, inducing effective diffusion. Numerical solutions show that such scale separation remains in the strongly nonlinear turbulent regime, provided there is sufficient drag at the bottom of the atmosphere and ocean. We compute the scaling laws governing the eddy-driven transport associated with baroclinic turbulence. First, we provide a theoretical underpinning for empirical scaling laws reported in previous studies, for different formulations of the bottom drag law. Second, these scaling laws are shown to provide an important first step toward an accurate local closure to predict the impact of baroclinic turbulence in setting the large-scale temperature profiles in the atmosphere and ocean. © 2020 National Academy of Sciences. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164302
Appears in Collections: 气候变化与战略
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作者单位: Gallet, B., Service de Physique de l'Etat Condensé, Commissariat à l'Energie Atomique Saclay, CNRS UMR 3680, Université Paris-Saclay, Gif-sur-Yvette, 91191, France; Ferrari, R., Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
Recommended Citation:
Gallet B.,Ferrari R.. The vortex gas scaling regime of baroclinic turbulence[J]. Proceedings of the National Academy of Sciences of the United States of America,2020-01-01,117(9)