Flux Richardson number stability function (Source File: cmue_rf.F90)


    subroutine cmue_rf(nlev)

In the ISPRAMIX ocean model (see Eifler and Schrimpf (1992)), another approach is used for considering stability effects on vertical mixing. The stability functions in this model are of the form:

$\displaystyle c_{\mu}=$const$\displaystyle =0.5,$ (199)

$\displaystyle c'_{\mu}=c_{\mu} f(R_f)=c_{\mu} \frac{1}{P_r^0}(1-R_f)^{1/2}.$ (200)

The neutral Prandtl number used there is $ P_r^0=0.7143$. The function $ f(R_f)$ is assumed to lay between the values 0.18 (corresponding to a supercritically stratified situation) and 2.0 (preventing it from growing too much under unstable conditions).

A formulation for $ (1-R_f)$ can be derived from the definition of the flux Richardson number

$\displaystyle R_f=\frac{c'_{\mu}}{c_{\mu}}R_i$ (201)

and (200), see Beckers (1995):

$\displaystyle (1-R_f)=[(\tilde R_i^2+1)^{1/2}-\tilde R_i]^2$ (202)


$\displaystyle \tilde R_i=\frac{0.5}{P_r^0} R_i$ (203)

where $ R_i$ is the gradient Richardson number.


    use turbulence, only: cm0_fix,Prandtl0_fix,xRF
    use turbulence, only: cmue1,cmue2,an,as
    integer, intent(in)                 :: nlev
    Original author(s):  Manuel Ruiz Villarreal, Hans Burchard
    $Log: cmue_rf.F90,v $
    Revision 1.8  2005-11-15 11:35:02  lars
    documentation finish for print
    Revision 1.7  2005/06/27 13:44:07  kbk
    modified + removed traling blanks
    Revision 1.6  2004/08/18 12:53:07  lars
    updated documentation
    Revision 1.5  2003/03/28 09:20:35  kbk
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    Revision 1.4  2003/03/28 08:37:27  kbk
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    Revision 1.3  2003/03/10 09:02:04  gotm
    Added new Generic Turbulence Model +
    improved documentation and cleaned up code
    Revision 1.2  2002/02/08 08:59:58  gotm
    Revision  2001/02/12 15:55:58  gotm
    initial import into CVS

Karsten Bolding 2012-01-24