Algebraic length-scale from ISPRAMIX (Source File: ispralength.F90)


    subroutine ispralength(nlev,NN,h,depth)

This subroutine calculates the lengthscale used in the ISPRAMIX model, see Eifler and Schrimpf (1992) and Demirov et al. (1998). In both mixing regions (close to the surface and the bottom), $ l$ is obtained from the formula

$\displaystyle l = \frac {\kappa \tilde z} {1+\frac {\kappa \tilde z} {c_2 \cdot h_m}} (1-R_f)^e$ (181)

where $ \tilde z$ is the distance from the interface (surface or bottom). The fraction in (181) predicts an approximation to a linear behavior of $ l$ near boundaries and a value proportional to the thickness of the mixed layer far from the interface, $ l=c_2 h_m$, where $ c_2=0.065$ is estimated from experimental data as discussed in Eifler and Schrimpf (1992). The factor $ (1-R_f)$, with the flux Richardson number $ R_f=-G/P$, accounts for the effect of stratification on the length-scale. The parameter $ e$ is here a tuning parameter (pers. comm. Walter Eifler, JRC, Ispra, Italy) which is usually set to $ e=1$.


    use turbulence, only: L,tke,k_min,eps_min,xRF,kappa,cde
    number of vertical layers
    integer,  intent(in)                :: nlev
    buoyancy frequency (1/s^2)
    REALTYPE, intent(in)                :: NN(0:nlev)
    layer thickness (m)
    REALTYPE, intent(in)                :: h(0:nlev)
    local depth (m)
    REALTYPE, intent(in)                :: depth
    Original author(s):  Manuel Ruiz Villarreal, Hans Burchard
    $Log: ispralength.F90,v $
    Revision 1.7  2005-11-15 11:35:02  lars
    documentation finish for print
    Revision 1.6  2005/06/27 13:44:07  kbk
    modified + removed traling blanks
    Revision 1.5  2003/03/28 09:20:35  kbk
    added new copyright to files
    Revision 1.4  2003/03/28 08:30:15  kbk
    removed tabs
    Revision 1.3  2003/03/10 09:02:05  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