/[lmdze]/trunk/Sources/phylmd/Interface_surf/fonte_neige.f
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Contents of /trunk/Sources/phylmd/Interface_surf/fonte_neige.f

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Revision 216 - (show annotations)
Tue Mar 28 15:36:53 2017 UTC (7 years, 1 month ago) by guez
File size: 4236 byte(s)
One less multiplication.
1 module fonte_neige_m
2
3 implicit none
4
5 contains
6
7 SUBROUTINE fonte_neige(nisurf, dtime, precip_rain, precip_snow, snow, qsol, &
8 tsurf_new, evap, fqcalving, ffonte, run_off_lic_0)
9
10 ! Routine de traitement de la fonte de la neige dans le cas du traitement
11 ! de sol simplifi\'e
12
13 ! Laurent Fairhead, March, 2001
14
15 USE fcttre, ONLY: foeew, qsatl, qsats
16 USE indicesol, ONLY: epsfra, is_lic, is_sic, is_ter
17 USE interface_surf, ONLY: run_off_lic, tau_calv
18 use nr_util, only: assert_eq
19 USE suphec_m, ONLY: rday, rlmlt, rtt
20
21 integer, intent(IN):: nisurf ! surface \`a traiter
22 real, intent(IN):: dtime ! pas de temps de la physique (en s)
23
24 real, intent(IN):: precip_rain(:) ! (knon)
25 ! precipitation, liquid water mass flux (kg / m2 / s), positive down
26
27 real, intent(IN):: precip_snow(:) ! (knon)
28 ! precipitation, solid water mass flux (kg / m2 / s), positive down
29
30 real, intent(INOUT):: snow(:) ! (knon)
31 ! column-density of mass of snow, in kg m-2
32
33 real, intent(INOUT):: qsol(:) ! (knon)
34 ! column-density of water in soil, in kg m-2
35
36 real, intent(INOUT):: tsurf_new(:) ! (knon) temp\'erature au sol
37 real, intent(IN):: evap(:) ! (knon)
38
39 real, intent(OUT):: fqcalving(:) ! (knon)
40 ! flux d'eau "perdue" par la surface et n\'ecessaire pour limiter la
41 ! hauteur de neige, en kg / m2 / s
42
43 real, intent(OUT):: ffonte(:) ! (knon)
44 ! flux thermique utilis\'é pour fondre la neige
45
46 real, intent(INOUT):: run_off_lic_0(:) ! (knon)
47 ! run off glacier du pas de temps pr\'ecedent
48
49 ! Local:
50
51 integer knon ! nombre de points \`a traiter
52 real, parameter:: snow_max=3000.
53 ! Masse maximum de neige (kg / m2). Au dessus de ce seuil, la neige
54 ! en exces "s'\'ecoule" (calving).
55
56 integer i
57 real fq_fonte
58 REAL bil_eau_s(size(precip_rain)) ! (knon) in kg m-2
59 real snow_evap(size(precip_rain)) ! (knon) in kg m-2 s-1
60 REAL, parameter:: chasno = 3.334E5 / (2.3867E6 * 0.15)
61 REAL, parameter:: chaice = 3.334E5 / (2.3867E6 * 0.15)
62 real, parameter:: max_eau_sol = 150. ! in kg m-2
63 real coeff_rel
64
65 !--------------------------------------------------------------------
66
67 knon = assert_eq((/size(precip_rain), size(precip_snow), size(snow), &
68 size(qsol), size(tsurf_new), size(evap), size(fqcalving), &
69 size(ffonte), size(run_off_lic_0)/), "fonte_neige knon")
70
71 coeff_rel = dtime / (tau_calv * rday)
72 WHERE (precip_snow > 0.) snow = snow + precip_snow * dtime
73
74 WHERE (evap > 0.)
75 snow_evap = MIN(snow / dtime, evap)
76 snow = snow - snow_evap * dtime
77 snow = MAX(0., snow)
78 elsewhere
79 snow_evap = 0.
80 end where
81
82 bil_eau_s = (precip_rain - evap + snow_evap) * dtime
83
84 ! Y a-t-il fonte de neige ?
85
86 do i = 1, knon
87 if ((snow(i) > epsfra .OR. nisurf == is_sic &
88 .OR. nisurf == is_lic) .AND. tsurf_new(i) >= RTT) then
89 fq_fonte = MIN(MAX((tsurf_new(i) - RTT) / chasno, 0.), snow(i))
90 ffonte(i) = fq_fonte * RLMLT / dtime
91 snow(i) = max(0., snow(i) - fq_fonte)
92 bil_eau_s(i) = bil_eau_s(i) + fq_fonte
93 tsurf_new(i) = tsurf_new(i) - fq_fonte * chasno
94
95 !IM cf. JLD/ GKtest fonte aussi pour la glace
96 IF (nisurf == is_sic .OR. nisurf == is_lic) THEN
97 fq_fonte = MAX((tsurf_new(i) - RTT) / chaice, 0.)
98 ffonte(i) = ffonte(i) + fq_fonte * RLMLT / dtime
99 bil_eau_s(i) = bil_eau_s(i) + fq_fonte
100 tsurf_new(i) = RTT
101 ENDIF
102 else
103 ffonte(i) = 0.
104 endif
105
106 ! S'il y a une hauteur trop importante de neige, elle s'\'ecoule
107 fqcalving(i) = max(0., snow(i) - snow_max) / dtime
108 snow(i) = min(snow(i), snow_max)
109
110 IF (nisurf == is_ter) then
111 qsol(i) = qsol(i) + bil_eau_s(i)
112 qsol(i) = MIN(qsol(i), max_eau_sol)
113 else if (nisurf == is_lic) then
114 run_off_lic(i) = (coeff_rel * fqcalving(i)) + &
115 (1. - coeff_rel) * run_off_lic_0(i)
116 run_off_lic_0(i) = run_off_lic(i)
117 run_off_lic(i) = run_off_lic(i) + bil_eau_s(i) / dtime
118 endif
119 enddo
120
121 END SUBROUTINE fonte_neige
122
123 end module fonte_neige_m

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