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module fonte_neige_m |
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|
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implicit none |
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|
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contains |
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SUBROUTINE fonte_neige(klon, knon, nisurf, dtime, tsurf, p1lay, beta, & |
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coef1lay, ps, precip_rain, precip_snow, snow, qsol, t1lay, q1lay, & |
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u1lay, v1lay, petAcoef, peqAcoef, petBcoef, peqBcoef, tsurf_new, evap, & |
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fqcalving, ffonte, run_off_lic_0) |
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|
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! Routine de traitement de la fonte de la neige dans le cas du traitement |
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! de sol simplifié |
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|
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! LF 03/2001 |
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|
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USE fcttre, ONLY: dqsatl, dqsats, foede, foeew, qsatl, qsats, thermcep |
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USE indicesol, ONLY: epsfra, is_lic, is_sic, is_ter |
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USE interface_surf, ONLY: run_off, run_off_lic, tau_calv |
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USE suphec_m, ONLY: rcpd, rd, rday, retv, rkappa, rlmlt, rlstt, rlvtt, rtt |
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USE yoethf_m, ONLY: r2es, r5ies, r5les, rvtmp2 |
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|
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integer, intent(IN):: klon |
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integer, intent(IN):: knon ! nombre de points à traiter |
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integer, intent(IN):: nisurf ! surface à traiter |
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real, intent(IN):: dtime ! pas de temps de la physique (en s) |
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real, dimension(klon), intent(IN):: tsurf, p1lay, beta, coef1lay |
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! tsurf temperature de surface |
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! p1lay pression 1er niveau (milieu de couche) |
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! beta evap reelle |
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! coef1lay coefficient d'echange |
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real, dimension(klon), intent(IN):: ps |
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! ps pression au sol |
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|
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real, intent(IN):: precip_rain(:) ! (knon) |
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! precipitation, liquid water mass flux (kg/m2/s), positive down |
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|
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real, intent(IN):: precip_snow(klon) |
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! precipitation, solid water mass flux (kg/m2/s), positive down |
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|
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real, intent(INOUT):: snow(klon) ! column-density of mass of snow, in kg m-2 |
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|
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real, intent(INOUT):: qsol(:) ! (knon) |
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! column-density of water in soil, in kg m-2 |
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|
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real, dimension(klon), intent(IN):: t1lay |
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real, dimension(klon), intent(IN):: q1lay |
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real, dimension(klon), intent(IN):: u1lay, v1lay |
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real, dimension(klon), intent(IN):: petAcoef, peqAcoef |
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! petAcoef coeff. A de la resolution de la CL pour t |
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! peqAcoef coeff. A de la resolution de la CL pour q |
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real, dimension(klon), intent(IN):: petBcoef, peqBcoef |
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! petBcoef coeff. B de la resolution de la CL pour t |
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! peqBcoef coeff. B de la resolution de la CL pour q |
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|
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real, intent(INOUT):: tsurf_new(klon), evap(klon) |
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! tsurf_new temperature au sol |
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|
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! Flux d'eau "perdue" par la surface et necessaire pour que limiter la |
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! hauteur de neige, en kg/m2/s |
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real, dimension(klon), intent(INOUT):: fqcalving |
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|
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! Flux thermique utiliser pour fondre la neige |
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real, dimension(klon), intent(INOUT):: ffonte |
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|
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real, dimension(klon), intent(INOUT):: run_off_lic_0 |
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! run_off_lic_0 run off glacier du pas de temps précedent |
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|
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! Local: |
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|
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real, parameter:: snow_max=3000. |
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! Masse maximum de neige (kg/m2). Au dessus de ce seuil, la neige |
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! en exces "s'ecoule" (calving) |
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|
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integer i |
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real, dimension(klon):: zx_mh, zx_nh, zx_oh |
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real, dimension(klon):: zx_mq, zx_nq, zx_oq |
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real, dimension(klon):: zx_pkh, zx_dq_s_dt, zx_qsat, zx_coef |
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real, dimension(klon):: zx_sl, zx_k1 |
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real, dimension(klon):: d_ts |
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real zdelta, zcvm5, zx_qs, zcor, zx_dq_s_dh |
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real fq_fonte |
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REAL bil_eau_s(knon) ! in kg m-2 |
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real snow_evap(klon) ! in kg m-2 s-1 |
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real, parameter:: t_grnd = 271.35, t_coup = 273.15 |
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REAL, parameter:: chasno = 3.334E5/(2.3867E6*0.15) |
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REAL, parameter:: chaice = 3.334E5/(2.3867E6*0.15) |
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real, parameter:: max_eau_sol = 150. ! in kg m-2 |
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real coeff_rel |
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|
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!-------------------------------------------------------------------- |
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|
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! Initialisations |
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coeff_rel = dtime/(tau_calv * rday) |
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bil_eau_s = 0. |
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DO i = 1, knon |
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zx_pkh(i) = (ps(i)/ps(i))**RKAPPA |
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IF (thermcep) THEN |
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zdelta=MAX(0., SIGN(1., rtt-tsurf(i))) |
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zcvm5 = R5LES*RLVTT*(1.-zdelta) + R5IES*RLSTT*zdelta |
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zcvm5 = zcvm5 / RCPD / (1. + RVTMP2*q1lay(i)) |
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zx_qs= r2es * FOEEW(tsurf(i), zdelta)/ps(i) |
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zx_qs=MIN(0.5, zx_qs) |
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zcor=1./(1.-retv*zx_qs) |
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zx_qs=zx_qs*zcor |
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zx_dq_s_dh = FOEDE(tsurf(i), zdelta, zcvm5, zx_qs, zcor) /RLVTT & |
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/ zx_pkh(i) |
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ELSE |
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IF (tsurf(i) < t_coup) THEN |
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zx_qs = qsats(tsurf(i)) / ps(i) |
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zx_dq_s_dh = dqsats(tsurf(i), zx_qs)/RLVTT / zx_pkh(i) |
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ELSE |
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zx_qs = qsatl(tsurf(i)) / ps(i) |
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zx_dq_s_dh = dqsatl(tsurf(i), zx_qs)/RLVTT / zx_pkh(i) |
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ENDIF |
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ENDIF |
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zx_dq_s_dt(i) = RCPD * zx_pkh(i) * zx_dq_s_dh |
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zx_qsat(i) = zx_qs |
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zx_coef(i) = coef1lay(i) * (1. + SQRT(u1lay(i)**2 + v1lay(i)**2)) & |
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* p1lay(i) / (RD * t1lay(i)) |
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ENDDO |
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|
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! Calcul de la temperature de surface |
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|
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! zx_sl = chaleur latente d'evaporation ou de sublimation |
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do i = 1, knon |
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zx_sl(i) = RLVTT |
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if (tsurf(i) < RTT) zx_sl(i) = RLSTT |
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zx_k1(i) = zx_coef(i) |
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enddo |
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|
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do i = 1, knon |
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! Q |
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zx_oq(i) = 1. - (beta(i) * zx_k1(i) * peqBcoef(i) * dtime) |
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zx_mq(i) = beta(i) * zx_k1(i) * (peqAcoef(i) - zx_qsat(i) & |
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+ zx_dq_s_dt(i) * tsurf(i)) / zx_oq(i) |
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zx_nq(i) = beta(i) * zx_k1(i) * (-1. * zx_dq_s_dt(i)) / zx_oq(i) |
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|
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! H |
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zx_oh(i) = 1. - (zx_k1(i) * petBcoef(i) * dtime) |
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zx_mh(i) = zx_k1(i) * petAcoef(i) / zx_oh(i) |
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zx_nh(i) = - (zx_k1(i) * RCPD * zx_pkh(i))/ zx_oh(i) |
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enddo |
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WHERE (precip_snow > 0.) snow = snow + precip_snow * dtime |
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|
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WHERE (evap > 0.) |
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snow_evap = MIN (snow / dtime, evap) |
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snow = snow - snow_evap * dtime |
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snow = MAX(0., snow) |
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elsewhere |
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snow_evap = 0. |
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end where |
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|
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bil_eau_s = precip_rain * dtime - (evap(:knon) - snow_evap(:knon)) * dtime |
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|
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! Y'a-t-il fonte de neige? |
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|
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ffonte=0. |
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do i = 1, knon |
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if ((snow(i) > epsfra .OR. nisurf == is_sic & |
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.OR. nisurf == is_lic) .AND. tsurf_new(i) >= RTT) then |
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fq_fonte = MIN(MAX((tsurf_new(i)-RTT)/chasno, 0.), snow(i)) |
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ffonte(i) = fq_fonte * RLMLT/dtime |
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snow(i) = max(0., snow(i) - fq_fonte) |
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bil_eau_s(i) = bil_eau_s(i) + fq_fonte |
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tsurf_new(i) = tsurf_new(i) - fq_fonte * chasno |
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!IM cf JLD/ GKtest fonte aussi pour la glace |
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IF (nisurf == is_sic .OR. nisurf == is_lic) THEN |
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fq_fonte = MAX((tsurf_new(i)-RTT)/chaice, 0.) |
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ffonte(i) = ffonte(i) + fq_fonte * RLMLT/dtime |
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bil_eau_s(i) = bil_eau_s(i) + fq_fonte |
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tsurf_new(i) = RTT |
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ENDIF |
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d_ts(i) = tsurf_new(i) - tsurf(i) |
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endif |
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|
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! S'il y a une hauteur trop importante de neige, elle s'écoule |
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fqcalving(i) = max(0., snow(i) - snow_max)/dtime |
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snow(i)=min(snow(i), snow_max) |
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|
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IF (nisurf == is_ter) then |
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qsol(i) = qsol(i) + bil_eau_s(i) |
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run_off(i) = run_off(i) + MAX(qsol(i) - max_eau_sol, 0.) |
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qsol(i) = MIN(qsol(i), max_eau_sol) |
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else if (nisurf == is_lic) then |
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run_off_lic(i) = (coeff_rel * fqcalving(i)) + & |
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(1. - coeff_rel) * run_off_lic_0(i) |
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run_off_lic_0(i) = run_off_lic(i) |
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run_off_lic(i) = run_off_lic(i) + bil_eau_s(i)/dtime |
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endif |
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enddo |
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|
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END SUBROUTINE fonte_neige |
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|
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end module fonte_neige_m |