Update the desctruction rate of buoyancy variance

INTERFACE:

    subroutine do_epsb(nlev,dt,u_taus,u_taub,z0s,z0b,h,NN,SS)

DESCRIPTION:

Based on the value of epsb_method, this routine calls the appropriate routines for calculating the molecular destruction rate of $k_b$, defined in (158). Presently, only a simple algebraic expression, described in section 4.7.33, is available in GOTM.

USES:

    IMPLICIT NONE

INPUT PARAMETERS:

    integer,  intent(in)                :: nlev
    REALTYPE, intent(in)                :: dt,u_taus,u_taub,z0s,z0b
    REALTYPE, intent(in)                :: h(0:nlev)
    REALTYPE, intent(in)                :: NN(0:nlev),SS(0:nlev)

REVISION HISTORY:

    Original author(s): Lars Umlauf