World Library  


Add to Book Shelf
Flag as Inappropriate
Email this Book

Mixed Layer Sub-mesoscale Parameterization – Part 1: Derivation and Assessment : Volume 6, Issue 3 (16/07/2010)

By Canuto, V. M.

Click here to view

Book Id: WPLBN0004020471
Format Type: PDF Article :
File Size: Pages 15
Reproduction Date: 2015

Title: Mixed Layer Sub-mesoscale Parameterization – Part 1: Derivation and Assessment : Volume 6, Issue 3 (16/07/2010)  
Author: Canuto, V. M.
Volume: Vol. 6, Issue 3
Language: English
Subject: Science, Ocean, Science
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
2010
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Citation

APA MLA Chicago

Dubovikov, M. S., & Canuto, V. M. (2010). Mixed Layer Sub-mesoscale Parameterization – Part 1: Derivation and Assessment : Volume 6, Issue 3 (16/07/2010). Retrieved from http://netlibrary.net/


Description
Description: NASA, Goddard Institute for Space Studies, New York, NY, 10025, USA. Several studies have shown that sub-mesoscales (SM ~1 km horizontal scale) play an important role in mixed layer dynamics. In particular, high resolution simulations have shown that in the case of strong down-front wind, the re-stratification induced by the SM is of the same order of the de-stratification induced by small scale turbulence, as well as of that induced by the Ekman velocity. These studies have further concluded that it has become necessary to include SM in ocean global circulation models (OGCMs), especially those used in climate studies.

The goal of our work is to derive and assess an analytic parameterization of the vertical tracer flux under baroclinic instabilities and wind of arbitrary directions and strength. To achieve this goal, we have divided the problem into two parts: first, in this work we derive and assess a parameterization of the SM vertical flux of an arbitrary tracer for ocean codes that resolve mesoscales, M, but not sub-mesoscales, SM. In Part 2, presented elsewhere, we have used the results of this work to derive a parameterization of SM fluxes for ocean codes that do not resolve either M or SM.

To carry out the first part of our work, we solve the SM dynamic equations including the non-linear terms for which we employ a closure developed and assessed in previous work. We present a detailed analysis for down-front and up-front winds with the following results:

(a) down-front wind (blowing in the direction of the surface geostrophic velocity) is the most favorable condition for generating vigorous SM eddies; the de-stratifying effect of the mean flow and re-stratifying effect of SM almost cancel each other out,

(b) in the up-front wind case (blowing in the direction opposite to the surface geostrophic velocity), strong winds prevents the SM generation while weak winds hinder the process but the eddies amplify the re-stratifying effect of the mean velocity,

(c) wind orthogonal to the geostrophic velocity. In this case, which was not considered in numerical simulations, we show that when the wind direction coincides with that of the horizontal buoyancy gradient, SM eddies are generated and their re-stratifying effect partly cancels the de-stratifying effect of the mean velocity. The case when wind direction is opposite to that of the horizontal buoyancy gradient, is analogous to the case of up-front winds.

In conclusion, the new multifaceted implications on the mixed layer stratification caused by the interplay of both strength and directions of the wind in relation to the buoyancy gradient disclosed by high resolution simulations have been reproduced by the present model.

The present results can be used in OGCMs that resolve M but not SM.


Summary
Mixed layer sub-mesoscale parameterization – Part 1: Derivation and assessment

Excerpt
Batchelor, G. K.: The theory of homogeneous turbulence, Cambridge Univ. Press, 195 pp., 1970.; Boccaletti, G., Ferrari, R., and Fox-Kemper, B.: Mixed layer instabilities and restratification, J. Phys. Oceanogr., 37, 2228–2250, 2007.; Canuto, V. M. and Dubovikov, M. S.: A new approach to turbulence, Int. J. Mod. Phys., 12(18), 3121–3152, 1997.; Canuto, V. M., Dubovikov, M. S., and Yu, G.: A dynamical model for turbulence, IX. Reynolds stress spectra for shear-driven flows, Phys. Fluids, 11(3), 676–691, 1999.; Canuto, V. M. and Dubovikov, M. S.: Modeling mesoscale eddies, cited as CD5, Ocean Model., 8, 1-30, 2005.; Canuto, V. M. and Dubovikov, M. S.: Dynamical model of mesoscales in z- coordinates, cited as CD6, Ocean Model., 11, 123–166, 2006.; Canuto, V. M. and Dubovikov, M. S.: Derivation and assessment of a mixed layer sub-mesoscale model, cited as CD9, Ocean Sci. Discuss., 6, 2157–2192, doi:10.5194/osd-6-2157-2009, 2009.; Canuto, V. M., Dubovikov, M. S., Luneva, M., Clayson, C. A., and Leboissetier, A.: Mixed layer mesoscales: a parameterization for OGCMs, Ocean Sci. Discuss., 7, 873–917, doi:10.5194/osd-7-873-2010, 2010.; Canuto, V. M. and Dubovikov, M. S.: Mixed layer sub-mesoscale parameterization: Part 2: Results for coarse resolution OGCMs, Ocean Sci. Discuss., 7, 1–14, doi:10.5194/osd-7-1-2010.2010, 2010.; Lapeyere, G., Klein, P., and Hua, B.C.: Oceanic re-stratification forced surface frontogenesis, J. Phys. Oceanogr., 36, 1577–1590, 2006.; Leith, C. E.: Atmospheric predictability and two-dimensional turbulence, J. Atmos. Sci., 28, 145–161, 1971.; Capet, X., McWilliams, J. C., Molemaker, M. J., and Shchepetkin, A. F.: Mesoscale to submesoscale transition in the California current system, Part I: flow structure, eddy flux, and observational tests, J. Phys. Oceanogr., 38, 29–43, 2008.; Chasnov, J. R.: Simulation of Kolmogorov inertial subrange using an improved subgrid model, Phys. Fluids, A3, 188–193, 1971.; de Boyer Montegut, C., Madec, G., Fisher, A. S., Lazar, A., and Iudicone, D.: Mixed layer depth over global ocean: an examination of profile data and a profile-based climatology, J. Geophys. Res., 109, C12003, doi:10.1029/2004JC002378, 2004.; Fox-Kemper, B., Ferrari, R., and Hallberg, R.: Parameterization of mixed layer eddies I: theory and diagnostics, J. Phys. Oceanogr., 38, 1145–1165, 2008.; Fox-Kemper, B. and Ferrari, R.: Parameterization of mixed layer eddies II: prognostics and impact, J. Phys. Oceanogr., 38, 1166–1179, 2008.; Herring, J. R. and Kraichnan, R. H.: Comparison of some approximations for isotropic turbulence, in: Statistical Models and Turbulence, edited by: Rosenblatt, M. and Van Atta, C., Springer-Verlag, New York, 147–194, 1971.; Hosegood, P. J., Gregg, M. C., and Alford, M. H.: Restratification of the Surface Mixed Layer with Submesoscale Lateral Density Gradients: Diagnosing the Importance of the Horizontal Dimension, J. Phys. Oceanogr., 38, 2438–2460, 2008.; Killworth, P. D.: On parameterization of eddy transport, J. Mar. Res., 55, 1171–1197, 1997.; Killworth, P. D.: Parameterization of eddy effect on mixed layer tracer transport: a linearized eddy perspective, J.Phys. Oceanogr., 35, 1717–1725, 2005.; Kraichnan, R. H.: An almost Markovian Galilean invariant turbulence model, J. Fluid Mech., 47, 513–524, 1971.; Kraichnan, R. H.: Statistical dynamics of two-dimensional flow, J. Fluid Mech., 67, 155–171, 1975.; Klein, P., Hua, B. L., Lapeyre, G., Capet, X., Le Gentil, S., and Sasaki, H.: Upper ocean turbulence from high resolution 3D simulation, J.Phys. Oceanogr., 38, 1748–1763, 2008.; Lesieur, M.: Turbulence in Fluids, section 3.3, Kluwer, Dordrecht, 212 pp., 1990.; Levy, M., Klein, P., and Treguier, A. M.: Impacts of sub-mesoscale physics on production and subduction of phytoplankton in an oligotrophic regime, J. Mar. Res., 59, 535–565, 2001.; Levy, M., Klein, P., Treguier, A. M., Iovino, D., Madec, G., Masson, S., an

 

Click To View

Additional Books


  • Towards High Resolution Mapping of 3-d M... (by )
  • Technical Note: a Low Cost Unmanned Aeri... (by )
  • The Circulation of Icelandic Waters – a ... (by )
  • Regional Impacts of Ocean Color on Tropi... (by )
  • Simulation of Tsunami Generation, Propag... (by )
  • Three Decades of Research on the Greater... (by )
  • Adapting to Life: Ocean Biogeochemical M... (by )
  • Comparative Heat and Gas Exchange Measur... (by )
  • A Nested Atlantic-mediterranean Sea Gene... (by )
  • A Parameter Model of Gas Exchange for th... (by )
  • Simulations of Argo Profilers and of Sur... (by )
  • Stability and Forcing of the Iceland-far... (by )
Scroll Left
Scroll Right

 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.