On the validity of single-parcel energetics to assess the importance of internal energy and compressibility effects in stratified fluids

Article English OPEN
Tailleux, Remi (2015)

It is often assumed on the basis of single-parcel energetics that compressible effects and conversions with internal energy are negligible whenever typical displacements of fluid parcels are small relative to the scale height of the fluid (defined as the ratio of the\ud squared speed of sound over gravitational acceleration). This paper shows that the above approach is flawed, however, and that a correct assessment of compressible effects and internal energy conversions requires considering the energetics of at least two parcels, or more generally, of mass conserving parcel re-arrangements. As a consequence, it is shown that it is the adiabatic lapse rate and its derivative with respect to pressure, rather than the scale height, which controls the relative importance of compressible effects and internal energy conversions when considering the global energy budget of a stratied fluid. Only when mass conservation is properly accounted for is it possible to explain why available internal energy can account for up to 40 percent of the total available potential energy in the oceans. This is considerably larger than the prediction of single-parcel energetics, according to which this number should be no more than about 2 percent.
  • References (21)
    21 references, page 1 of 3

    Batchelor, G.K. 1967 An introduction to Fluid Dynamics. Cambridge University Press. 615 pp.

    de Szoeke, R. A. & Samelson, R. M. 2002 The duality between Boussinesq and nonBoussinesq hydrostatic equations of motion. J. Phys. Oceanogr. 30, 2194{2203.

    Eden, C., L. Czeschel & D. Olbers 2014 Toward energetically consistent ocean models. J. Phys. Oceanogr. 44, 3160{3184.

    Gade, H. G. & Gustafsson, K. E. 2004 Application of classical thermodynamic principles to the study of oceanic overturning circulation. Tellus 56A, 371{386.

    Huang, R. X. 2005 Available potential energy in the world's oceans. J. Mar. Res. 63, 141{158.

    IOC, SCOR & IAPSO 2010 The international thermodynamic equation of seawater | 2010: Calculations and use of thermodynamic properties. Intergovernmental Oceanographic Commission, Manuals and Guides No 56, UNESCO (English), 196 pp.

    Kuhlbrodt, T., A. Griesel, M. Montoya, A. Levermann, M. Hofmann, & S. Rahmstorf 2007 On the driving processes of the Atlantic meridional overturning circulation. Rev. Geophys., 45, RG2001 doi:10.1029/2004RG000166.

    McDougall, T. J. 1987 Neutral surfaces. J. Phys. Oceanogr. 17, 1950{1964.

    McDougall, T. J. & P. M. Barker2011 Getting started with TEOS-10 and the Gibbs Seawater (GSW) Oceaongraphic Toolbox. 28 pp. SCOR/IAPSO WG127, ISBN 978-0-646- 55621-5.

    McDougall, T. J. & R. Feistel2003 What causes the adiabatic lapse rate? Deep-Sea Res. I 50, 1523{1535.

  • Metrics
    0
    views in OpenAIRE
    0
    views in local repository
    30
    downloads in local repository

    The information is available from the following content providers:

    From Number Of Views Number Of Downloads
    Central Archive at the University of Reading - IRUS-UK 0 30
Share - Bookmark