phylmd/Interface_surf/fonte_neige.f

module fonte_neige_m

  implicit none

contains

  SUBROUTINE fonte_neige(nisurf, dtime, tsurf, p1lay, beta, coef1lay, ps, &
       precip_rain, precip_snow, snow, qsol, t1lay, q1lay, u1lay, v1lay, &
       petAcoef, peqAcoef, petBcoef, peqBcoef, tsurf_new, evap, fqcalving, &
       ffonte, run_off_lic_0)

    ! Routine de traitement de la fonte de la neige dans le cas du traitement
    ! de sol simplifi\'e

    ! LF 03/2001

    USE fcttre, ONLY: foeew, qsatl, qsats, thermcep
    USE indicesol, ONLY: epsfra, is_lic, is_sic, is_ter
    USE interface_surf, ONLY: run_off, run_off_lic, tau_calv
    use nr_util, only: assert_eq
    USE suphec_m, ONLY: rcpd, rday, retv, rlmlt, rlstt, rlvtt, rtt
    USE yoethf_m, ONLY: r2es, r5ies, r5les, rvtmp2

    integer, intent(IN):: nisurf ! surface \`a traiter
    real, intent(IN):: dtime ! pas de temps de la physique (en s)
    real, dimension(:), intent(IN):: tsurf, p1lay, beta, coef1lay ! (knon)
    ! tsurf temperature de surface
    ! p1lay pression 1er niveau (milieu de couche)
    ! beta evap reelle
    ! coef1lay coefficient d'echange
    real, dimension(:), intent(IN):: ps ! (knon)
    ! ps pression au sol

    real, intent(IN):: precip_rain(:) ! (knon)
    ! precipitation, liquid water mass flux (kg/m2/s), positive down

    real, intent(IN):: precip_snow(:) ! (knon)
    ! precipitation, solid water mass flux (kg/m2/s), positive down

    real, intent(INOUT):: snow(:) ! (knon)
    ! column-density of mass of snow, in kg m-2

    real, intent(INOUT):: qsol(:) ! (knon)
    ! column-density of water in soil, in kg m-2

    real, dimension(:), intent(IN):: t1lay ! (knon)
    real, dimension(:), intent(IN):: q1lay ! (knon)
    real, dimension(:), intent(IN):: u1lay, v1lay ! (knon)
    real, dimension(:), intent(IN):: petAcoef, peqAcoef ! (knon)
    ! petAcoef coeff. A de la resolution de la CL pour t
    ! peqAcoef coeff. A de la resolution de la CL pour q
    real, dimension(:), intent(IN):: petBcoef, peqBcoef ! (knon)
    ! petBcoef coeff. B de la resolution de la CL pour t
    ! peqBcoef coeff. B de la resolution de la CL pour q

    real, intent(INOUT):: tsurf_new(:)
    ! tsurf_new temperature au sol

    real, intent(IN):: evap(:) ! (knon)

    ! Flux d'eau "perdue" par la surface et necessaire pour que limiter la
    ! hauteur de neige, en kg/m2/s
    real, intent(OUT):: fqcalving(:) ! (knon)

    ! Flux thermique utiliser pour fondre la neige
    real, intent(OUT):: ffonte(:) ! (knon)

    real, dimension(:), intent(INOUT):: run_off_lic_0 ! (knon)
    ! run_off_lic_0 run off glacier du pas de temps pr\'ecedent

    ! Local:

    integer knon ! nombre de points \`a traiter
    real, parameter:: snow_max=3000.
    ! Masse maximum de neige (kg/m2). Au dessus de ce seuil, la neige
    ! en exces "s'ecoule" (calving)

    integer i
    logical zdelta
    real zcvm5, zx_qs, zcor
    real fq_fonte
    REAL bil_eau_s(size(ps)) ! in kg m-2
    real snow_evap(size(ps)) ! in kg m-2 s-1
    real, parameter:: t_grnd = 271.35, t_coup = 273.15
    REAL, parameter:: chasno = 3.334E5/(2.3867E6*0.15)
    REAL, parameter:: chaice = 3.334E5/(2.3867E6*0.15)
    real, parameter:: max_eau_sol = 150. ! in kg m-2
    real coeff_rel

    !--------------------------------------------------------------------

    knon = assert_eq((/size(tsurf), size(p1lay), size(beta), size(coef1lay), &
         size(ps), size(precip_rain), size(precip_snow), size(snow), &
         size(qsol), size(t1lay), size(q1lay), size(u1lay), size(v1lay), &
         size(petAcoef), size(peqAcoef), size(petBcoef), size(peqBcoef), &
         size(tsurf_new), size(evap), size(fqcalving), size(ffonte), &
         size(run_off_lic_0)/), "fonte_neige knon")

    ! Initialisations
    coeff_rel = dtime/(tau_calv * rday)
    bil_eau_s = 0.
    DO i = 1, knon
       IF (thermcep) THEN
          zdelta= rtt >= tsurf(i)
          zcvm5 = merge(R5IES*RLSTT, R5LES*RLVTT, zdelta)
          zcvm5 = zcvm5 / RCPD / (1. + RVTMP2*q1lay(i))
          zx_qs= r2es * FOEEW(tsurf(i), zdelta)/ps(i)
          zx_qs=MIN(0.5, zx_qs)
          zcor=1./(1.-retv*zx_qs)
          zx_qs=zx_qs*zcor
       ELSE
          IF (tsurf(i) < t_coup) THEN
             zx_qs = qsats(tsurf(i)) / ps(i)
          ELSE
             zx_qs = qsatl(tsurf(i)) / ps(i)
          ENDIF
       ENDIF
    ENDDO

    ! Calcul de la temperature de surface

    WHERE (precip_snow > 0.) snow = snow + precip_snow * dtime

    WHERE (evap > 0.)
       snow_evap = MIN(snow / dtime, evap)
       snow = snow - snow_evap * dtime
       snow = MAX(0., snow)
    elsewhere
       snow_evap = 0.
    end where

    bil_eau_s = precip_rain * dtime - (evap(:knon) - snow_evap(:knon)) * dtime

    ! Y'a-t-il fonte de neige?

    ffonte=0.
    do i = 1, knon
       if ((snow(i) > epsfra .OR. nisurf == is_sic &
            .OR. nisurf == is_lic) .AND. tsurf_new(i) >= RTT) then
          fq_fonte = MIN(MAX((tsurf_new(i)-RTT)/chasno, 0.), snow(i))
          ffonte(i) = fq_fonte * RLMLT/dtime
          snow(i) = max(0., snow(i) - fq_fonte)
          bil_eau_s(i) = bil_eau_s(i) + fq_fonte
          tsurf_new(i) = tsurf_new(i) - fq_fonte * chasno
          !IM cf JLD/ GKtest fonte aussi pour la glace
          IF (nisurf == is_sic .OR. nisurf == is_lic) THEN
             fq_fonte = MAX((tsurf_new(i)-RTT)/chaice, 0.)
             ffonte(i) = ffonte(i) + fq_fonte * RLMLT/dtime
             bil_eau_s(i) = bil_eau_s(i) + fq_fonte
             tsurf_new(i) = RTT
          ENDIF
       endif

       ! S'il y a une hauteur trop importante de neige, elle s'\'ecoule
       fqcalving(i) = max(0., snow(i) - snow_max)/dtime
       snow(i)=min(snow(i), snow_max)

       IF (nisurf == is_ter) then
          qsol(i) = qsol(i) + bil_eau_s(i)
          run_off(i) = run_off(i) + MAX(qsol(i) - max_eau_sol, 0.)
          qsol(i) = MIN(qsol(i), max_eau_sol)
       else if (nisurf == is_lic) then
          run_off_lic(i) = (coeff_rel * fqcalving(i)) + &
               (1. - coeff_rel) * run_off_lic_0(i)
          run_off_lic_0(i) = run_off_lic(i)
          run_off_lic(i) = run_off_lic(i) + bil_eau_s(i)/dtime
       endif
    enddo

  END SUBROUTINE fonte_neige

end module fonte_neige_m
1	module fonte_neige_m
2
3	implicit none
4
5	contains
6
7	SUBROUTINE fonte_neige(nisurf, dtime, tsurf, p1lay, beta, coef1lay, ps, &
8	precip_rain, precip_snow, snow, qsol, t1lay, q1lay, u1lay, v1lay, &
9	petAcoef, peqAcoef, petBcoef, peqBcoef, tsurf_new, evap, fqcalving, &
10	ffonte, run_off_lic_0)
11
12	! Routine de traitement de la fonte de la neige dans le cas du traitement
13	! de sol simplifi\'e
14
15	! LF 03/2001
16
17	USE fcttre, ONLY: foeew, qsatl, qsats, thermcep
18	USE indicesol, ONLY: epsfra, is_lic, is_sic, is_ter
19	USE interface_surf, ONLY: run_off, run_off_lic, tau_calv
20	use nr_util, only: assert_eq
21	USE suphec_m, ONLY: rcpd, rday, retv, rlmlt, rlstt, rlvtt, rtt
22	USE yoethf_m, ONLY: r2es, r5ies, r5les, rvtmp2
23
24	integer, intent(IN):: nisurf ! surface \`a traiter
25	real, intent(IN):: dtime ! pas de temps de la physique (en s)
26	real, dimension(:), intent(IN):: tsurf, p1lay, beta, coef1lay ! (knon)
27	! tsurf temperature de surface
28	! p1lay pression 1er niveau (milieu de couche)
29	! beta evap reelle
30	! coef1lay coefficient d'echange
31	real, dimension(:), intent(IN):: ps ! (knon)
32	! ps pression au sol
33
34	real, intent(IN):: precip_rain(:) ! (knon)
35	! precipitation, liquid water mass flux (kg/m2/s), positive down
36
37	real, intent(IN):: precip_snow(:) ! (knon)
38	! precipitation, solid water mass flux (kg/m2/s), positive down
39
40	real, intent(INOUT):: snow(:) ! (knon)
41	! column-density of mass of snow, in kg m-2
42
43	real, intent(INOUT):: qsol(:) ! (knon)
44	! column-density of water in soil, in kg m-2
45
46	real, dimension(:), intent(IN):: t1lay ! (knon)
47	real, dimension(:), intent(IN):: q1lay ! (knon)
48	real, dimension(:), intent(IN):: u1lay, v1lay ! (knon)
49	real, dimension(:), intent(IN):: petAcoef, peqAcoef ! (knon)
50	! petAcoef coeff. A de la resolution de la CL pour t
51	! peqAcoef coeff. A de la resolution de la CL pour q
52	real, dimension(:), intent(IN):: petBcoef, peqBcoef ! (knon)
53	! petBcoef coeff. B de la resolution de la CL pour t
54	! peqBcoef coeff. B de la resolution de la CL pour q
55
56	real, intent(INOUT):: tsurf_new(:)
57	! tsurf_new temperature au sol
58
59	real, intent(IN):: evap(:) ! (knon)
60
61	! Flux d'eau "perdue" par la surface et necessaire pour que limiter la
62	! hauteur de neige, en kg/m2/s
63	real, intent(OUT):: fqcalving(:) ! (knon)
64
65	! Flux thermique utiliser pour fondre la neige
66	real, intent(OUT):: ffonte(:) ! (knon)
67
68	real, dimension(:), intent(INOUT):: run_off_lic_0 ! (knon)
69	! run_off_lic_0 run off glacier du pas de temps pr\'ecedent
70
71	! Local:
72
73	integer knon ! nombre de points \`a traiter
74	real, parameter:: snow_max=3000.
75	! Masse maximum de neige (kg/m2). Au dessus de ce seuil, la neige
76	! en exces "s'ecoule" (calving)
77
78	integer i
79	logical zdelta
80	real zcvm5, zx_qs, zcor
81	real fq_fonte
82	REAL bil_eau_s(size(ps)) ! in kg m-2
83	real snow_evap(size(ps)) ! in kg m-2 s-1
84	real, parameter:: t_grnd = 271.35, t_coup = 273.15
85	REAL, parameter:: chasno = 3.334E5/(2.3867E6*0.15)
86	REAL, parameter:: chaice = 3.334E5/(2.3867E6*0.15)
87	real, parameter:: max_eau_sol = 150. ! in kg m-2
88	real coeff_rel
89
90	!--------------------------------------------------------------------
91
92	knon = assert_eq((/size(tsurf), size(p1lay), size(beta), size(coef1lay), &
93	size(ps), size(precip_rain), size(precip_snow), size(snow), &
94	size(qsol), size(t1lay), size(q1lay), size(u1lay), size(v1lay), &
95	size(petAcoef), size(peqAcoef), size(petBcoef), size(peqBcoef), &
96	size(tsurf_new), size(evap), size(fqcalving), size(ffonte), &
97	size(run_off_lic_0)/), "fonte_neige knon")
98
99	! Initialisations
100	coeff_rel = dtime/(tau_calv * rday)
101	bil_eau_s = 0.
102	DO i = 1, knon
103	IF (thermcep) THEN
104	zdelta= rtt >= tsurf(i)
105	zcvm5 = merge(R5IESRLSTT, R5LESRLVTT, zdelta)
106	zcvm5 = zcvm5 / RCPD / (1. + RVTMP2*q1lay(i))
107	zx_qs= r2es * FOEEW(tsurf(i), zdelta)/ps(i)
108	zx_qs=MIN(0.5, zx_qs)
109	zcor=1./(1.-retv*zx_qs)
110	zx_qs=zx_qs*zcor
111	ELSE
112	IF (tsurf(i) < t_coup) THEN
113	zx_qs = qsats(tsurf(i)) / ps(i)
114	ELSE
115	zx_qs = qsatl(tsurf(i)) / ps(i)
116	ENDIF
117	ENDIF
118	ENDDO
119
120	! Calcul de la temperature de surface
121
122	WHERE (precip_snow > 0.) snow = snow + precip_snow * dtime
123
124	WHERE (evap > 0.)
125	snow_evap = MIN(snow / dtime, evap)
126	snow = snow - snow_evap * dtime
127	snow = MAX(0., snow)
128	elsewhere
129	snow_evap = 0.
130	end where
131
132	bil_eau_s = precip_rain * dtime - (evap(:knon) - snow_evap(:knon)) * dtime
133
134	! Y'a-t-il fonte de neige?
135
136	ffonte=0.
137	do i = 1, knon
138	if ((snow(i) > epsfra .OR. nisurf == is_sic &
139	.OR. nisurf == is_lic) .AND. tsurf_new(i) >= RTT) then
140	fq_fonte = MIN(MAX((tsurf_new(i)-RTT)/chasno, 0.), snow(i))
141	ffonte(i) = fq_fonte * RLMLT/dtime
142	snow(i) = max(0., snow(i) - fq_fonte)
143	bil_eau_s(i) = bil_eau_s(i) + fq_fonte
144	tsurf_new(i) = tsurf_new(i) - fq_fonte * chasno
145	!IM cf JLD/ GKtest fonte aussi pour la glace
146	IF (nisurf == is_sic .OR. nisurf == is_lic) THEN
147	fq_fonte = MAX((tsurf_new(i)-RTT)/chaice, 0.)
148	ffonte(i) = ffonte(i) + fq_fonte * RLMLT/dtime
149	bil_eau_s(i) = bil_eau_s(i) + fq_fonte
150	tsurf_new(i) = RTT
151	ENDIF
152	endif
153
154	! S'il y a une hauteur trop importante de neige, elle s'\'ecoule
155	fqcalving(i) = max(0., snow(i) - snow_max)/dtime
156	snow(i)=min(snow(i), snow_max)
157
158	IF (nisurf == is_ter) then
159	qsol(i) = qsol(i) + bil_eau_s(i)
160	run_off(i) = run_off(i) + MAX(qsol(i) - max_eau_sol, 0.)
161	qsol(i) = MIN(qsol(i), max_eau_sol)
162	else if (nisurf == is_lic) then
163	run_off_lic(i) = (coeff_rel * fqcalving(i)) + &
164	(1. - coeff_rel) * run_off_lic_0(i)
165	run_off_lic_0(i) = run_off_lic(i)
166	run_off_lic(i) = run_off_lic(i) + bil_eau_s(i)/dtime
167	endif
168	enddo
169
170	END SUBROUTINE fonte_neige
171
172	end module fonte_neige_m