/[lmdze]/trunk/libf/phylmd/clcdrag.f90
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Contents of /trunk/libf/phylmd/clcdrag.f90

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Revision 40 - (show annotations)
Tue Feb 22 13:49:36 2011 UTC (13 years, 3 months ago) by guez
File size: 3658 byte(s)
"alpha" useless, always 0, in "exner_hyb".

1 SUBROUTINE clcdrag(klon, knon, nsrf, zxli, u, v, t, q, zgeop, ts, qsurf, &
2 rugos, pcfm, pcfh)
3
4 ! From LMDZ4/libf/phylmd/clcdrag.F90, version 1.1.1.1 2004/05/19 12:53:07
5
6 use indicesol
7 use SUPHEC_M
8 use yoethf_m
9
10 IMPLICIT NONE
11
12 ! Objet : calcul des cdrags pour le moment (pcfm) et les flux de
13 ! chaleur sensible et latente (pcfh).
14
15 ! knon----input-I- nombre de points pour un type de surface
16 ! nsrf----input-I- indice pour le type de surface; voir indicesol.inc
17 ! zxli----input-L- calcul des cdrags selon Laurent Li
18 ! u-------input-R- vent zonal au 1er niveau du modele
19 ! v-------input-R- vent meridien au 1er niveau du modele
20 ! t-------input-R- temperature de l'air au 1er niveau du modele
21 ! q-------input-R- humidite de l'air au 1er niveau du modele
22 ! ts------input-R- temperature de l'air a la surface
23 ! qsurf---input-R- humidite de l'air a la surface
24 ! rugos---input-R- rugosite
25
26 ! pcfm---output-R- cdrag pour le moment
27 ! pcfh---output-R- cdrag pour les flux de chaleur latente et sensible
28
29 INTEGER, intent(in) :: klon
30 ! dimension de la grille physique (= nb_pts_latitude X nb_pts_longitude)
31
32 INTEGER, intent(in) :: knon, nsrf
33 LOGICAL, intent(in) :: zxli
34 REAL, intent(in), dimension(klon) :: u, v, t, q
35 REAL, intent(in):: zgeop(klon) ! géopotentiel au 1er niveau du modèle
36 REAL, intent(in), dimension(klon) :: ts, qsurf
37 REAL, intent(in), dimension(klon) :: rugos
38 REAL, intent(out), dimension(klon) :: pcfm, pcfh
39
40 ! Quelques constantes et options:
41 REAL, PARAMETER :: ckap=0.40, cb=5.0, cc=5.0, cd=5.0, cepdu2=(0.1)**2
42
43 ! Variables locales :
44 INTEGER :: i
45 REAL :: zdu2, ztsolv, ztvd, zscf
46 REAL :: zucf, zcr
47 REAL :: friv, frih
48 REAL, dimension(klon) :: zcfm1, zcfm2
49 REAL, dimension(klon) :: zcfh1, zcfh2
50 REAL, dimension(klon) :: zcdn
51 REAL, dimension(klon) :: zri
52
53 ! Fonctions thermodynamiques et fonctions d'instabilite
54 REAL :: fsta, fins, x
55 fsta(x) = 1.0 / (1.0+10.0*x*(1+8.0*x))
56 fins(x) = SQRT(1.0-18.0*x)
57
58 !--------------------------------------------------------------------
59
60 ! Calculer le frottement au sol (Cdrag)
61
62 DO i = 1, knon
63 zdu2 = max(cepdu2,u(i)**2+v(i)**2)
64 ztsolv = ts(i) * (1.0+RETV*qsurf(i))
65 ztvd = (t(i)+zgeop(i)/RCPD/(1.+RVTMP2*q(i))) &
66 *(1.+RETV*q(i))
67 zri(i) = zgeop(i)*(ztvd-ztsolv)/(zdu2*ztvd)
68 zcdn(i) = (ckap/log(1.+zgeop(i)/(RG*rugos(i))))**2
69
70 IF (zri(i) .gt. 0.) THEN
71 ! situation stable
72 zri(i) = min(20.,zri(i))
73 IF (.NOT.zxli) THEN
74 zscf = SQRT(1.+cd*ABS(zri(i)))
75 FRIV = AMAX1(1. / (1.+2.*CB*zri(i)/ZSCF), 0.1)
76 zcfm1(i) = zcdn(i) * FRIV
77 FRIH = AMAX1(1./ (1.+3.*CB*zri(i)*ZSCF), 0.1 )
78 zcfh1(i) = 0.8 * zcdn(i) * FRIH
79 pcfm(i) = zcfm1(i)
80 pcfh(i) = zcfh1(i)
81 ELSE
82 pcfm(i) = zcdn(i)* fsta(zri(i))
83 pcfh(i) = zcdn(i)* fsta(zri(i))
84 ENDIF
85 ELSE
86 ! situation instable
87 IF (.NOT.zxli) THEN
88 zucf = 1./(1.+3.0*cb*cc*zcdn(i)*SQRT(ABS(zri(i)) &
89 *(1.0+zgeop(i)/(RG*rugos(i)))))
90 zcfm2(i) = zcdn(i)*amax1((1.-2.0*cb*zri(i)*zucf),0.1)
91 zcfh2(i) = 0.8 * zcdn(i)*amax1((1.-3.0*cb*zri(i)*zucf),0.1)
92 pcfm(i) = zcfm2(i)
93 pcfh(i) = zcfh2(i)
94 ELSE
95 pcfm(i) = zcdn(i)* fins(zri(i))
96 pcfh(i) = zcdn(i)* fins(zri(i))
97 ENDIF
98 zcr = (0.0016/(zcdn(i)*SQRT(zdu2)))*ABS(ztvd-ztsolv)**(1./3.)
99 IF(nsrf == is_oce) pcfh(i) = 0.8 * zcdn(i) &
100 * (1. + zcr**1.25)**(1. / 1.25)
101 ENDIF
102 END DO
103
104 END SUBROUTINE clcdrag

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