Update diffusivities (Kolmogorov-Prandtl relation)

INTERFACE:

   subroutine kolpran(nlev)

DESCRIPTION:

Eddy viscosity and diffusivity are calculated by means of the relation of Kolmogorov and Prandtl from the updated values of $k$, $l$ and the stability functions according to (44). In addition, the counter-gradient term $\tilde{\Gamma}_B = \epsilon \Gamma$ is updated, see (35) and (75).

Note, that this routine relies on the fact that the lowest and uppermost values of the stability functions and of $k$, $l$, and $\Gamma$ have been computed using the correct boundary conditions. No special treatment of $\nu_t$, $\nu^B_t$, and $\tilde{\Gamma}_B$ at the boundaries is processed.

USES:

   IMPLICIT NONE

INPUT PARAMETERS:

   integer, intent(in)       :: nlev

REVISION HISTORY:

   Original author(s): Karsten Bolding, Hans Burchard,
                       Manuel Ruiz Villarreal, Lars Umlauf