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

    ! Laurent Fairhead, March, 2001

    USE fcttre, ONLY: foeew, qsatl, qsats, thermcep
    USE indicesol, ONLY: epsfra, is_lic, is_sic, is_ter
    USE interface_surf, ONLY: 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, intent(IN):: tsurf(:) ! (knon) temperature de surface
    real, intent(IN):: p1lay(:) ! (knon) pression 1er niveau (milieu de couche)
    real, intent(IN):: beta(:) ! (knon) evap reelle
    real, intent(IN):: coef1lay(:) ! (knon) coefficient d'echange
    real, intent(IN):: ps(:) ! (knon) 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, intent(IN):: t1lay(:) ! (knon)
    real, intent(IN):: q1lay(:) ! (knon)
    real, intent(IN):: u1lay(:), v1lay(:) ! (knon)

    real, intent(IN):: petAcoef(:), peqAcoef(:) ! (knon)
    ! coefficients A de la r\'esolution de la couche limite pour t et q

    real, intent(IN):: petBcoef(:), peqBcoef(:) ! (knon)
    ! coefficients B de la r\'esolution de la couche limite pour t et q

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

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

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

    real, intent(OUT):: ffonte(:) ! (knon)
    ! flux thermique utilis\'é pour fondre la neige

    real, intent(INOUT):: run_off_lic_0(:) ! (knon)
    ! 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_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)
          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	! Laurent Fairhead, March, 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_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, intent(IN):: tsurf(:) ! (knon) temperature de surface
27	real, intent(IN):: p1lay(:) ! (knon) pression 1er niveau (milieu de couche)
28	real, intent(IN):: beta(:) ! (knon) evap reelle
29	real, intent(IN):: coef1lay(:) ! (knon) coefficient d'echange
30	real, intent(IN):: ps(:) ! (knon) pression au sol
31
32	real, intent(IN):: precip_rain(:) ! (knon)
33	! precipitation, liquid water mass flux (kg / m2 / s), positive down
34
35	real, intent(IN):: precip_snow(:) ! (knon)
36	! precipitation, solid water mass flux (kg / m2 / s), positive down
37
38	real, intent(INOUT):: snow(:) ! (knon)
39	! column-density of mass of snow, in kg m-2
40
41	real, intent(INOUT):: qsol(:) ! (knon)
42	! column-density of water in soil, in kg m-2
43
44	real, intent(IN):: t1lay(:) ! (knon)
45	real, intent(IN):: q1lay(:) ! (knon)
46	real, intent(IN):: u1lay(:), v1lay(:) ! (knon)
47
48	real, intent(IN):: petAcoef(:), peqAcoef(:) ! (knon)
49	! coefficients A de la r\'esolution de la couche limite pour t et q
50
51	real, intent(IN):: petBcoef(:), peqBcoef(:) ! (knon)
52	! coefficients B de la r\'esolution de la couche limite pour t et q
53
54	real, intent(INOUT):: tsurf_new(:)
55	! tsurf_new temperature au sol
56
57	real, intent(IN):: evap(:) ! (knon)
58
59	real, intent(OUT):: fqcalving(:) ! (knon)
60	! flux d'eau "perdue" par la surface et n\'ecessaire pour limiter la
61	! hauteur de neige, en kg / m2 / s
62
63	real, intent(OUT):: ffonte(:) ! (knon)
64	! flux thermique utilis\'é pour fondre la neige
65
66	real, intent(INOUT):: run_off_lic_0(:) ! (knon)
67	! run off glacier du pas de temps pr\'ecedent
68
69	! Local:
70
71	integer knon ! nombre de points \`a traiter
72	real, parameter:: snow_max=3000.
73	! Masse maximum de neige (kg / m2). Au dessus de ce seuil, la neige
74	! en exces "s'ecoule" (calving)
75
76	integer i
77	logical zdelta
78	real zcvm5, zx_qs, zcor
79	real fq_fonte
80	REAL bil_eau_s(size(ps)) ! in kg m-2
81	real snow_evap(size(ps)) ! in kg m-2 s-1
82	real, parameter:: t_coup = 273.15
83	REAL, parameter:: chasno = 3.334E5 / (2.3867E6*0.15)
84	REAL, parameter:: chaice = 3.334E5 / (2.3867E6*0.15)
85	real, parameter:: max_eau_sol = 150. ! in kg m-2
86	real coeff_rel
87
88	!--------------------------------------------------------------------
89
90	knon = assert_eq((/size(tsurf), size(p1lay), size(beta), size(coef1lay), &
91	size(ps), size(precip_rain), size(precip_snow), size(snow), &
92	size(qsol), size(t1lay), size(q1lay), size(u1lay), size(v1lay), &
93	size(petAcoef), size(peqAcoef), size(petBcoef), size(peqBcoef), &
94	size(tsurf_new), size(evap), size(fqcalving), size(ffonte), &
95	size(run_off_lic_0)/), "fonte_neige knon")
96
97	! Initialisations
98	coeff_rel = dtime / (tau_calv * rday)
99	bil_eau_s = 0.
100	DO i = 1, knon
101	IF (thermcep) THEN
102	zdelta= rtt >= tsurf(i)
103	zcvm5 = merge(R5IESRLSTT, R5LESRLVTT, zdelta)
104	zcvm5 = zcvm5 / RCPD / (1. + RVTMP2*q1lay(i))
105	zx_qs= r2es * FOEEW(tsurf(i), zdelta) / ps(i)
106	zx_qs=MIN(0.5, zx_qs)
107	zcor=1. / (1.-retv*zx_qs)
108	zx_qs=zx_qs*zcor
109	ELSE
110	IF (tsurf(i) < t_coup) THEN
111	zx_qs = qsats(tsurf(i)) / ps(i)
112	ELSE
113	zx_qs = qsatl(tsurf(i)) / ps(i)
114	ENDIF
115	ENDIF
116	ENDDO
117
118	! Calcul de la temperature de surface
119
120	WHERE (precip_snow > 0.) snow = snow + precip_snow * dtime
121
122	WHERE (evap > 0.)
123	snow_evap = MIN(snow / dtime, evap)
124	snow = snow - snow_evap * dtime
125	snow = MAX(0., snow)
126	elsewhere
127	snow_evap = 0.
128	end where
129
130	bil_eau_s = precip_rain * dtime - (evap(:knon) - snow_evap(:knon)) * dtime
131
132	! Y a-t-il fonte de neige ?
133
134	ffonte=0.
135	do i = 1, knon
136	if ((snow(i) > epsfra .OR. nisurf == is_sic &
137	.OR. nisurf == is_lic) .AND. tsurf_new(i) >= RTT) then
138	fq_fonte = MIN(MAX((tsurf_new(i)-RTT) / chasno, 0.), snow(i))
139	ffonte(i) = fq_fonte * RLMLT / dtime
140	snow(i) = max(0., snow(i) - fq_fonte)
141	bil_eau_s(i) = bil_eau_s(i) + fq_fonte
142	tsurf_new(i) = tsurf_new(i) - fq_fonte * chasno
143	!IM cf JLD/ GKtest fonte aussi pour la glace
144	IF (nisurf == is_sic .OR. nisurf == is_lic) THEN
145	fq_fonte = MAX((tsurf_new(i)-RTT) / chaice, 0.)
146	ffonte(i) = ffonte(i) + fq_fonte * RLMLT / dtime
147	bil_eau_s(i) = bil_eau_s(i) + fq_fonte
148	tsurf_new(i) = RTT
149	ENDIF
150	endif
151
152	! S'il y a une hauteur trop importante de neige, elle s'\'ecoule
153	fqcalving(i) = max(0., snow(i) - snow_max) / dtime
154	snow(i)=min(snow(i), snow_max)
155
156	IF (nisurf == is_ter) then
157	qsol(i) = qsol(i) + bil_eau_s(i)
158	qsol(i) = MIN(qsol(i), max_eau_sol)
159	else if (nisurf == is_lic) then
160	run_off_lic(i) = (coeff_rel * fqcalving(i)) + &
161	(1. - coeff_rel) * run_off_lic_0(i)
162	run_off_lic_0(i) = run_off_lic(i)
163	run_off_lic(i) = run_off_lic(i) + bil_eau_s(i) / dtime
164	endif
165	enddo
166
167	END SUBROUTINE fonte_neige
168
169	end module fonte_neige_m