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*** S/P kdifsimp
subroutine kdifsimp(km,ue,z,z0,f,kmin,nk,n) 2
#include "impnone.cdk"
integer nk,n,it,i,j
real km(n,nk),ue(n),z(n,nk),z0(n),f(n)
real a,b,ah,fmin,h,G,lnro,ci,par,ff,df
real kmin,fe
*Author
* Yves Delage (August 1999)
*
*Revisions
* 001 S. Laroche (Nov 2002) - bug fix in lnro
*
*
*Object
* Calculates vertical diffusion coefficient and friction velocity for
* simplified physics using resistance theory (JAS 25, 1015-1020)
*
*Arguments
* - Output -
*KM diffusion coefficients (m2/s)
*UE linearized friction velocity, used to calculate transfer
* coefficient for the surface layer (m/s)
* - Input -
*Z height of levels for KM (m)
*Z0 roughness length (m)
*F Coriolis factor (1/s)
*KMIN minimum value for km (DIFBAK)
*NK number of levels
*N horizontal dimension
*
#include "consphy.cdk"
*
**
* constantes physiques
data a,b /1.0, 5.0 /
save a,b
* parametres formels
data G, ah, fmin /10., 0.05, 5.e-5 /
save G, ah, fmin
* calcul de la vitesse de frottement
do 50 i=1,n
fe=max(abs(f(i)),fmin)
lnro = log(G/(sqrt(fe*1.e-4)*z0(i)))
ci=30.
* do it=1,3
par=sqrt((KARMAN*ci)**2-b**2)
ff=a-lnro+log(ci)+par
df=1/ci+1/par*KARMAN**2*ci
ci=ci-ff/df
par=sqrt((KARMAN*ci)**2-b**2)
ff=a-lnro+log(ci)+par
df=1/ci+1/par*KARMAN**2*ci
ci=ci-ff/df
par=sqrt((KARMAN*ci)**2-b**2)
ff=a-lnro+log(ci)+par
df=1/ci+1/par*KARMAN**2*ci
ci=ci-ff/df
ue(i)=G/ci
50 continue
* calcul du coefficient de diffusion
do 100 j=1,nk
do 100 i=1,n
h=ah*ue(i)/max(abs(f(i)),fmin)
km(i,j)=max(kmin,KARMAN*(z(i,j)+z0(i))*ue(i)*exp(-z(i,j)/h))
100 continue
return
end