Update the buoyancy variance

INTERFACE:

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

DESCRIPTION:

Based on the value of kb_method, this routine calls the appropriate routines for calculating (half) the buoyancy variance $k_b$ defined in (50). The user has the choice between a simple algebraic expression, described in section 4.7.31, and a dynamic equation for $k_b$, described in section 4.7.26.

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