| 1 | MODULE icethd_pnd |
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| 2 | !!====================================================================== |
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| 3 | !! *** MODULE icethd_pnd *** |
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| 4 | !! sea-ice: Melt ponds on top of sea ice |
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| 5 | !!====================================================================== |
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| 6 | !! history : ! 2012 (O. Lecomte) Adaptation from Flocco and Turner |
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| 7 | !! ! 2017 (M. Vancoppenolle, O. Lecomte, C. Rousset) Implementation |
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| 8 | !! 4.0 ! 2018 (many people) SI3 [aka Sea Ice cube] |
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| 9 | !!---------------------------------------------------------------------- |
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| 10 | #if defined key_si3 |
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| 11 | !!---------------------------------------------------------------------- |
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| 12 | !! 'key_si3' : SI3 sea-ice model |
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| 13 | !!---------------------------------------------------------------------- |
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| 14 | !! ice_thd_pnd_init : some initialization and namelist read |
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| 15 | !! ice_thd_pnd : main calling routine |
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| 16 | !!---------------------------------------------------------------------- |
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| 17 | USE phycst ! physical constants |
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| 18 | USE dom_oce ! ocean space and time domain |
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| 19 | USE ice ! sea-ice: variables |
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| 20 | USE ice1D ! sea-ice: thermodynamics variables |
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| 21 | USE icetab ! sea-ice: 1D <==> 2D transformation |
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| 22 | ! |
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| 23 | USE in_out_manager ! I/O manager |
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| 24 | USE lib_mpp ! MPP library |
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| 25 | USE lib_fortran ! fortran utilities (glob_sum + no signed zero) |
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| 26 | USE timing ! Timing |
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| 27 | |
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| 28 | IMPLICIT NONE |
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| 29 | PRIVATE |
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| 30 | |
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| 31 | PUBLIC ice_thd_pnd_init ! routine called by icestp.F90 |
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| 32 | PUBLIC ice_thd_pnd ! routine called by icestp.F90 |
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| 33 | |
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| 34 | INTEGER :: nice_pnd ! choice of the type of pond scheme |
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| 35 | ! ! associated indices: |
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| 36 | INTEGER, PARAMETER :: np_pndNO = 0 ! No pond scheme |
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| 37 | INTEGER, PARAMETER :: np_pndCST = 1 ! Constant ice pond scheme |
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| 38 | INTEGER, PARAMETER :: np_pndLEV = 2 ! Level ice pond scheme |
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| 39 | INTEGER, PARAMETER :: np_pndTOPO = 3 ! Level ice pond scheme |
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| 40 | |
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| 41 | !! * Substitutions |
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| 42 | # include "vectopt_loop_substitute.h90" |
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| 43 | !!---------------------------------------------------------------------- |
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| 44 | !! NEMO/ICE 4.0 , NEMO Consortium (2018) |
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| 45 | !! $Id$ |
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| 46 | !! Software governed by the CeCILL license (see ./LICENSE) |
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| 47 | !!---------------------------------------------------------------------- |
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| 48 | CONTAINS |
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| 49 | |
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| 50 | SUBROUTINE ice_thd_pnd |
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| 51 | !!------------------------------------------------------------------- |
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| 52 | !! *** ROUTINE ice_thd_pnd *** |
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| 53 | !! |
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| 54 | !! ** Purpose : change melt pond fraction and thickness |
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| 55 | !! |
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| 56 | !!------------------------------------------------------------------- |
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| 57 | ! |
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| 58 | SELECT CASE ( nice_pnd ) |
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| 59 | ! |
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| 60 | CASE (np_pndCST) ; CALL pnd_CST !== Constant melt ponds ==! |
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| 61 | ! |
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| 62 | CASE (np_pndLEV) ; CALL pnd_LEV !== Level ice melt ponds ==! |
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| 63 | ! |
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| 64 | CASE (np_pndTOPO) ; CALL pnd_TOPO !== Topographic melt ponds ==! |
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| 65 | ! |
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| 66 | END SELECT |
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| 67 | ! |
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| 68 | END SUBROUTINE ice_thd_pnd |
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| 69 | |
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| 70 | |
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| 71 | SUBROUTINE pnd_CST |
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| 72 | !!------------------------------------------------------------------- |
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| 73 | !! *** ROUTINE pnd_CST *** |
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| 74 | !! |
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| 75 | !! ** Purpose : Compute melt pond evolution |
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| 76 | !! |
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| 77 | !! ** Method : Melt pond fraction and thickness are prescribed |
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| 78 | !! to non-zero values when t_su = 0C |
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| 79 | !! |
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| 80 | !! ** Tunable parameters : pond fraction (rn_apnd), pond depth (rn_hpnd) |
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| 81 | !! |
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| 82 | !! ** Note : Coupling with such melt ponds is only radiative |
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| 83 | !! Advection, ridging, rafting... are bypassed |
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| 84 | !! |
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| 85 | !! ** References : Bush, G.W., and Trump, D.J. (2017) |
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| 86 | !!------------------------------------------------------------------- |
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| 87 | INTEGER :: ji ! loop indices |
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| 88 | !!------------------------------------------------------------------- |
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| 89 | DO ji = 1, npti |
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| 90 | ! |
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| 91 | IF( a_i_1d(ji) > 0._wp .AND. t_su_1d(ji) >= rt0 ) THEN |
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| 92 | h_ip_1d(ji) = rn_hpnd |
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| 93 | a_ip_1d(ji) = rn_apnd * a_i_1d(ji) |
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| 94 | h_il_1d(ji) = 0._wp ! no pond lids whatsoever |
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| 95 | ELSE |
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| 96 | h_ip_1d(ji) = 0._wp |
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| 97 | a_ip_1d(ji) = 0._wp |
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| 98 | h_il_1d(ji) = 0._wp |
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| 99 | ENDIF |
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| 100 | ! |
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| 101 | END DO |
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| 102 | ! |
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| 103 | END SUBROUTINE pnd_CST |
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| 104 | |
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| 105 | |
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| 106 | SUBROUTINE pnd_LEV |
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| 107 | !!------------------------------------------------------------------- |
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| 108 | !! *** ROUTINE pnd_LEV *** |
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| 109 | !! |
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| 110 | !! ** Purpose : Compute melt pond evolution |
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| 111 | !! |
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| 112 | !! ** Method : A fraction of meltwater is accumulated in ponds and sent to ocean when surface is freezing |
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| 113 | !! We work with volumes and then redistribute changes into thickness and concentration |
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| 114 | !! assuming linear relationship between the two. |
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| 115 | !! |
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| 116 | !! ** Action : - pond growth: Vp = Vp + dVmelt --- from Holland et al 2012 --- |
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| 117 | !! dVmelt = (1-r)/rhow * ( rhoi*dh_i + rhos*dh_s ) * a_i |
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| 118 | !! dh_i = meltwater from ice surface melt |
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| 119 | !! dh_s = meltwater from snow melt |
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| 120 | !! (1-r) = fraction of melt water that is not flushed |
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| 121 | !! |
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| 122 | !! - limtations: a_ip must not exceed (1-r)*a_i |
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| 123 | !! h_ip must not exceed 0.5*h_i |
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| 124 | !! |
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| 125 | !! - pond shrinking: |
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| 126 | !! if lids: Vp = Vp -dH * a_ip |
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| 127 | !! dH = lid thickness change. Retrieved from this eq.: --- from Flocco et al 2010 --- |
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| 128 | !! |
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| 129 | !! rhoi * Lf * dH/dt = ki * MAX(Tp-Tsu,0) / H |
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| 130 | !! H = lid thickness |
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| 131 | !! Lf = latent heat of fusion |
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| 132 | !! Tp = -2C |
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| 133 | !! |
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| 134 | !! And solved implicitely as: |
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| 135 | !! H(t+dt)**2 -H(t) * H(t+dt) -ki * (Tp-Tsu) * dt / (rhoi*Lf) = 0 |
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| 136 | !! |
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| 137 | !! if no lids: Vp = Vp * exp(0.01*MAX(Tp-Tsu,0)/Tp) --- from Holland et al 2012 --- |
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| 138 | !! |
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| 139 | !! - Flushing: w = -perm/visc * rho_oce * grav * Hp / Hi --- from Flocco et al 2007 --- |
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| 140 | !! perm = permability of sea-ice |
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| 141 | !! visc = water viscosity |
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| 142 | !! Hp = height of top of the pond above sea-level |
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| 143 | !! Hi = ice thickness thru which there is flushing |
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| 144 | !! |
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| 145 | !! - Corrections: remove melt ponds when lid thickness is 10 times the pond thickness |
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| 146 | !! |
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| 147 | !! - pond thickness and area is retrieved from pond volume assuming a linear relationship between h_ip and a_ip: |
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| 148 | !! a_ip/a_i = a_ip_frac = h_ip / zaspect |
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| 149 | !! |
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| 150 | !! ** Tunable parameters : ln_pnd_lids, rn_apnd_max, rn_apnd_min |
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| 151 | !! |
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| 152 | !! ** Note : mostly stolen from CICE |
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| 153 | !! |
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| 154 | !! ** References : Flocco and Feltham (JGR, 2007) |
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| 155 | !! Flocco et al (JGR, 2010) |
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| 156 | !! Holland et al (J. Clim, 2012) |
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| 157 | !!------------------------------------------------------------------- |
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| 158 | |
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| 159 | REAL(wp), DIMENSION(nlay_i) :: ztmp ! temporary array |
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| 160 | !! |
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| 161 | REAL(wp), PARAMETER :: zaspect = 0.8_wp ! pond aspect ratio |
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| 162 | REAL(wp), PARAMETER :: zTp = -2._wp ! reference temperature |
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| 163 | REAL(wp), PARAMETER :: zvisc = 1.79e-3_wp ! water viscosity |
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| 164 | !! |
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| 165 | REAL(wp) :: zfr_mlt, zdv_mlt ! fraction and volume of available meltwater retained for melt ponding |
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| 166 | REAL(wp) :: zdv_frz, zdv_flush ! Amount of melt pond that freezes, flushes |
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| 167 | REAL(wp) :: zhp ! heigh of top of pond lid wrt ssh |
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| 168 | REAL(wp) :: zv_ip_max ! max pond volume allowed |
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| 169 | REAL(wp) :: zdT ! zTp-t_su |
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| 170 | REAL(wp) :: zsbr ! Brine salinity |
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| 171 | REAL(wp) :: zperm ! permeability of sea ice |
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| 172 | REAL(wp) :: zfac, zdum ! temporary arrays |
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| 173 | REAL(wp) :: z1_rhow, z1_aspect, z1_Tp ! inverse |
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| 174 | !! |
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| 175 | INTEGER :: ji, jk ! loop indices |
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| 176 | |
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| 177 | !!------------------------------------------------------------------- |
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| 178 | |
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| 179 | z1_rhow = 1._wp / rhow |
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| 180 | z1_aspect = 1._wp / zaspect |
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| 181 | z1_Tp = 1._wp / zTp |
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| 182 | |
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| 183 | DO ji = 1, npti |
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| 184 | ! !----------------------------------------------------! |
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| 185 | IF( h_i_1d(ji) < rn_himin .OR. a_i_1d(ji) < epsi10 ) THEN ! Case ice thickness < rn_himin or tiny ice fraction ! |
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| 186 | ! !----------------------------------------------------! |
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| 187 | !--- Remove ponds on thin ice or tiny ice fractions |
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| 188 | a_ip_1d(ji) = 0._wp |
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| 189 | h_ip_1d(ji) = 0._wp |
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| 190 | h_il_1d(ji) = 0._wp |
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| 191 | ! !--------------------------------! |
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| 192 | ELSE ! Case ice thickness >= rn_himin ! |
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| 193 | ! !--------------------------------! |
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| 194 | v_ip_1d(ji) = h_ip_1d(ji) * a_ip_1d(ji) ! retrieve volume from thickness |
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| 195 | v_il_1d(ji) = h_il_1d(ji) * a_ip_1d(ji) |
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| 196 | ! |
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| 197 | !------------------! |
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| 198 | ! case ice melting ! |
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| 199 | !------------------! |
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| 200 | ! |
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| 201 | !--- available meltwater for melt ponding ---! |
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| 202 | zdum = -( dh_i_sum(ji)*rhoi + dh_s_mlt(ji)*rhos ) * z1_rhow * a_i_1d(ji) |
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| 203 | zfr_mlt = rn_apnd_min + ( rn_apnd_max - rn_apnd_min ) * at_i_1d(ji) ! = ( 1 - r ) = fraction of melt water that is not flushed |
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| 204 | zdv_mlt = MAX( 0._wp, zfr_mlt * zdum ) ! >0, max for roundoff errors? |
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| 205 | ! |
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| 206 | !--- overflow ---! |
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| 207 | ! If pond area exceeds zfr_mlt * a_i_1d(ji) then reduce the pond volume |
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| 208 | ! a_ip_max = zfr_mlt * a_i |
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| 209 | ! => from zaspect = h_ip / (a_ip / a_i), set v_ip_max as: |
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| 210 | zv_ip_max = zfr_mlt**2 * a_i_1d(ji) * zaspect |
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| 211 | zdv_mlt = MAX( 0._wp, MIN( zdv_mlt, zv_ip_max - v_ip_1d(ji) ) ) |
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| 212 | |
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| 213 | ! If pond depth exceeds half the ice thickness then reduce the pond volume |
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| 214 | ! h_ip_max = 0.5 * h_i |
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| 215 | ! => from zaspect = h_ip / (a_ip / a_i), set v_ip_max as: |
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| 216 | zv_ip_max = z1_aspect * a_i_1d(ji) * 0.25 * h_i_1d(ji) * h_i_1d(ji) ! MV dimensions are wrong here or comment is unclear |
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| 217 | zdv_mlt = MAX( 0._wp, MIN( zdv_mlt, zv_ip_max - v_ip_1d(ji) ) ) |
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| 218 | |
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| 219 | !--- Pond growing ---! |
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| 220 | v_ip_1d(ji) = v_ip_1d(ji) + zdv_mlt |
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| 221 | ! |
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| 222 | !--- Lid melting ---! |
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| 223 | IF( ln_pnd_lids ) v_il_1d(ji) = MAX( 0._wp, v_il_1d(ji) - zdv_mlt ) ! must be bounded by 0 |
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| 224 | |
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| 225 | ! |
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| 226 | !--- mass flux ---! |
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| 227 | IF( zdv_mlt > 0._wp ) THEN |
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| 228 | ! MV add comment on what that mass flux means |
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| 229 | ! water removed from fw flux due to melt pond growth |
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| 230 | zfac = zdv_mlt * rhow * r1_rdtice ! melt pond mass flux < 0 [kg.m-2.s-1] |
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| 231 | wfx_pnd_1d(ji) = wfx_pnd_1d(ji) - zfac |
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| 232 | ! |
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| 233 | ! MV |
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| 234 | ! why surface melt and snow fluxes must be adjusted is not clear |
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| 235 | ! sounds like things are counted twice |
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| 236 | ! |
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| 237 | zdum = zfac / ( wfx_snw_sum_1d(ji) + wfx_sum_1d(ji) ) ! adjust ice/snow melting flux > 0 to balance melt pond flux |
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| 238 | wfx_snw_sum_1d(ji) = wfx_snw_sum_1d(ji) * (1._wp + zdum) |
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| 239 | wfx_sum_1d(ji) = wfx_sum_1d(ji) * (1._wp + zdum) |
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| 240 | ENDIF |
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| 241 | |
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| 242 | !-------------------! |
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| 243 | ! case ice freezing ! i.e. t_su_1d(ji) < (zTp+rt0) |
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| 244 | !-------------------! |
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| 245 | ! |
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| 246 | zdT = MAX( zTp+rt0 - t_su_1d(ji), 0._wp ) |
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| 247 | ! |
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| 248 | !--- Pond contraction (due to refreezing) ---! |
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| 249 | IF( ln_pnd_lids ) THEN |
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| 250 | ! |
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| 251 | !--- Lid growing and subsequent pond shrinking ---! |
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| 252 | zdv_frz = 0.5_wp * MAX( 0._wp, -v_il_1d(ji) + & ! Flocco 2010 (eq. 5) solved implicitly as aH**2 + bH + c = 0 |
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| 253 | & SQRT( v_il_1d(ji)**2 + a_ip_1d(ji)**2 * 4._wp * rcnd_i * zdT * rdt_ice / (rLfus * rhow) ) ) ! max for roundoff errors |
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| 254 | |
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| 255 | ! Lid growing |
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| 256 | v_il_1d(ji) = MAX( 0._wp, v_il_1d(ji) + zdv_frz ) |
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| 257 | |
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| 258 | ! Pond shrinking |
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| 259 | v_ip_1d(ji) = MAX( 0._wp, v_ip_1d(ji) - zdv_frz ) |
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| 260 | |
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| 261 | ELSE |
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| 262 | ! Pond shrinking |
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| 263 | v_ip_1d(ji) = v_ip_1d(ji) * EXP( 0.01_wp * zdT * z1_Tp ) ! Holland 2012 (eq. 6) |
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| 264 | ENDIF |
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| 265 | ! |
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| 266 | !--- Set new pond area and depth ---! assuming linear relation between h_ip and a_ip_frac |
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| 267 | ! v_ip = h_ip * a_ip |
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| 268 | ! a_ip/a_i = a_ip_frac = h_ip / zaspect (cf Holland 2012, fitting SHEBA so that knowing v_ip we can distribute it to a_ip and h_ip) |
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| 269 | a_ip_1d(ji) = MIN( a_i_1d(ji), SQRT( v_ip_1d(ji) * z1_aspect * a_i_1d(ji) ) ) ! make sure a_ip < a_i |
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| 270 | h_ip_1d(ji) = zaspect * a_ip_1d(ji) / a_i_1d(ji) |
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| 271 | |
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| 272 | !---------------! |
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| 273 | ! Pond flushing ! |
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| 274 | !---------------! |
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| 275 | ! height of top of the pond above sea-level |
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| 276 | zhp = ( h_i_1d(ji) * ( rau0 - rhoi ) + h_ip_1d(ji) * ( rau0 - rhow * a_ip_1d(ji) / a_i_1d(ji) ) ) * r1_rau0 |
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| 277 | |
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| 278 | ! Calculate the permeability of the ice (Assur 1958, see Flocco 2010) |
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| 279 | ! zsbr = - ( t_i_1d(ji,jk) - rt0 ) / rTmlt |
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| 280 | DO jk = 1, nlay_i |
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| 281 | zsbr = - 1.2_wp & |
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| 282 | & - 21.8_wp * ( t_i_1d(ji,jk) - rt0 ) & |
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| 283 | & - 0.919_wp * ( t_i_1d(ji,jk) - rt0 )**2 & |
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| 284 | & - 0.0178_wp * ( t_i_1d(ji,jk) - rt0 )**3 |
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| 285 | ! zsbr = - ( t_i_1d(ji,jk) - rt0 ) / rTmlt |
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| 286 | ztmp(jk) = sz_i_1d(ji,jk) / zsbr |
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| 287 | END DO |
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| 288 | |
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| 289 | zperm = MAX( 0._wp, 3.e-08_wp * MINVAL(ztmp)**3 ) |
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| 290 | |
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| 291 | ! Do the drainage using Darcy's law |
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| 292 | zdv_flush = -zperm * rau0 * grav * zhp * rdt_ice / (zvisc * h_i_1d(ji)) * a_ip_1d(ji) |
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| 293 | zdv_flush = MAX( zdv_flush, -v_ip_1d(ji) ) |
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| 294 | v_ip_1d(ji) = v_ip_1d(ji) + zdv_flush |
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| 295 | |
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| 296 | !--- Set new pond area and depth ---! assuming linear relation between h_ip and a_ip_frac |
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| 297 | a_ip_1d(ji) = MIN( a_i_1d(ji), SQRT( v_ip_1d(ji) * z1_aspect * a_i_1d(ji) ) ) ! make sure a_ip < a_i |
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| 298 | h_ip_1d(ji) = zaspect * a_ip_1d(ji) / a_i_1d(ji) |
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| 299 | |
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| 300 | !--- Corrections and lid thickness ---! |
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| 301 | IF( ln_pnd_lids ) THEN |
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| 302 | !--- retrieve lid thickness from volume ---! |
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| 303 | IF( a_ip_1d(ji) > epsi10 ) THEN ; h_il_1d(ji) = v_il_1d(ji) / a_ip_1d(ji) |
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| 304 | ELSE ; h_il_1d(ji) = 0._wp |
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| 305 | ENDIF |
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| 306 | !--- remove ponds if lids are much larger than ponds ---! |
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| 307 | IF ( h_il_1d(ji) > h_ip_1d(ji) * 10._wp ) THEN |
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| 308 | a_ip_1d(ji) = 0._wp |
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| 309 | h_ip_1d(ji) = 0._wp |
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| 310 | h_il_1d(ji) = 0._wp |
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| 311 | ENDIF |
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| 312 | ENDIF |
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| 313 | ! |
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| 314 | ENDIF |
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| 315 | |
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| 316 | END DO |
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| 317 | ! |
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| 318 | END SUBROUTINE pnd_LEV |
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| 319 | |
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| 320 | SUBROUTINE pnd_TOPO (aice, aicen, & |
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| 321 | vice, vicen, & |
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| 322 | vsnon, & |
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| 323 | ticen, salin, & |
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| 324 | a_ip_frac, h_ip, & |
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| 325 | Tsfc ) |
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| 326 | |
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| 327 | !!------------------------------------------------------------------- |
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| 328 | !! *** ROUTINE pnd_TOPO *** |
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| 329 | !! |
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| 330 | !! ** Purpose : Compute melt pond evolution |
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| 331 | !! |
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| 332 | !! ** Purpose : Compute melt pond evolution based on the ice |
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| 333 | !! topography as inferred from the ice thickness |
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| 334 | !! distribution. |
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| 335 | !! |
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| 336 | !! ** Method : This code is initially based on Flocco and Feltham |
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| 337 | !! (2007) and Flocco et al. (2010). More to come... |
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| 338 | !! |
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| 339 | !! ** Tunable parameters : |
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| 340 | !! |
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| 341 | !! ** Note : |
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| 342 | !! |
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| 343 | !! ** References |
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| 344 | !! Flocco, D. and D. L. Feltham, 2007. A continuum model of melt pond |
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| 345 | !! evolution on Arctic sea ice. J. Geophys. Res. 112, C08016, doi: |
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| 346 | !! 10.1029/2006JC003836. |
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| 347 | !! Flocco, D., D. L. Feltham and A. K. Turner, 2010. Incorporation of |
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| 348 | !! a physically based melt pond scheme into the sea ice component of a |
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| 349 | !! climate model. J. Geophys. Res. 115, C08012, |
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| 350 | !! doi: 10.1029/2009JC005568. |
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| 351 | !! |
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| 352 | !!------------------------------------------------------------------- |
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| 353 | |
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| 354 | !js 190423: the lid on melt ponds appears only in the analog subroutine of CICE 5.1.2 |
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| 355 | |
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| 356 | REAL (wp), DIMENSION (jpi,jpj), & |
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| 357 | INTENT(IN) :: & |
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| 358 | aice, & ! total ice area fraction |
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| 359 | vice ! total ice volume (m) |
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| 360 | |
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| 361 | REAL (wp), DIMENSION (jpi,jpj,jpl), & |
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| 362 | INTENT(IN) :: & |
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| 363 | aicen, & ! ice area fraction, per category |
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| 364 | vsnon, & ! snow volume, per category (m) |
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| 365 | vicen ! ice volume, per category (m) |
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| 366 | |
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| 367 | REAL (wp), DIMENSION (jpi,jpj,nlay_i,jpl), & |
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| 368 | INTENT(IN) :: & |
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| 369 | ticen, & ! ice temperature per category (K) |
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| 370 | salin |
|---|
| 371 | |
|---|
| 372 | REAL (wp), DIMENSION (jpi,jpj,jpl), & |
|---|
| 373 | INTENT(INOUT) :: & |
|---|
| 374 | a_ip_frac , & ! pond area fraction of ice, per ice category |
|---|
| 375 | h_ip ! pond depth, per ice category (m) |
|---|
| 376 | |
|---|
| 377 | REAL (wp), DIMENSION (jpi,jpj,jpl), & |
|---|
| 378 | INTENT(IN) :: & |
|---|
| 379 | Tsfc ! snow/sea ice surface temperature |
|---|
| 380 | |
|---|
| 381 | ! local variables |
|---|
| 382 | REAL (wp), DIMENSION (jpi,jpj,jpl) :: & |
|---|
| 383 | zTsfcn, & ! ice/snow surface temperature (C) |
|---|
| 384 | zvolpn ! pond volume per unit area, per category (m) |
|---|
| 385 | |
|---|
| 386 | REAL (wp), DIMENSION (jpi,jpj,jpl) :: & |
|---|
| 387 | zrfrac, & ! fraction of available meltwater retained for melt ponding |
|---|
| 388 | zapondn,& ! pond area fraction, per category |
|---|
| 389 | zhpondn ! pond depth, per category (m) |
|---|
| 390 | |
|---|
| 391 | REAL (wp), DIMENSION (jpi,jpj) :: & |
|---|
| 392 | zvolp, & ! total volume of pond, per unit area of pond (m) |
|---|
| 393 | zwfx_tmp ! temporary array for melt water |
|---|
| 394 | |
|---|
| 395 | REAL (wp) :: & |
|---|
| 396 | zhi, & ! ice thickness (m) |
|---|
| 397 | zTavg, & ! mean surface temperature across categories (C) |
|---|
| 398 | z1_rhow, & ! inverse freshwater density |
|---|
| 399 | zdTs, & ! temperature difference for freeze-up (C) |
|---|
| 400 | zvpold, & ! dummy pond volume |
|---|
| 401 | zdvn ! change in melt pond volume for fresh water budget |
|---|
| 402 | |
|---|
| 403 | INTEGER, DIMENSION (jpi*jpj) :: & |
|---|
| 404 | indxi, indxj ! compressed indices for cells with ice melting |
|---|
| 405 | |
|---|
| 406 | INTEGER :: ij,icells,ji,jj,jl ! loop indices |
|---|
| 407 | |
|---|
| 408 | REAL (wp), PARAMETER :: & |
|---|
| 409 | zr1_rlfus = 1._wp / 0.334e+6 / 917._wp , & ! (J/m^3) |
|---|
| 410 | zTp = -0.15_wp, & ! pond freezing temperature (C) |
|---|
| 411 | zmin_volp = 1.e-4_wp, & ! minimum pond volume (m) |
|---|
| 412 | zrexp = 0.01_wp, & ! constant melt pond freeze-up rate |
|---|
| 413 | z01 = 0.01_wp, & |
|---|
| 414 | z25 = 0.25_wp, & |
|---|
| 415 | z5 = 0.5_wp |
|---|
| 416 | |
|---|
| 417 | z1_rhow = 1. / rhow |
|---|
| 418 | |
|---|
| 419 | !--------------------------------------------------------------- |
|---|
| 420 | ! Initialization |
|---|
| 421 | !--------------------------------------------------------------- |
|---|
| 422 | zhpondn (:,:,:) = 0._wp |
|---|
| 423 | zapondn (:,:,:) = 0._wp |
|---|
| 424 | zvolpn (:,:,:) = 0._wp |
|---|
| 425 | |
|---|
| 426 | zTsfcn(:,:,:) = Tsfc(:,:,:) - rt0 ! Convert in Celsius |
|---|
| 427 | |
|---|
| 428 | IF ( ln_pnd_fw ) THEN |
|---|
| 429 | v_ip_b(:,:,:) = v_ip(:,:,:) |
|---|
| 430 | ELSE |
|---|
| 431 | v_ip_b(:,:,:) = 0._wp |
|---|
| 432 | ENDIF |
|---|
| 433 | |
|---|
| 434 | !------------------------------------------------------------------ |
|---|
| 435 | ! Available melt water for melt ponding and corresponding fraction |
|---|
| 436 | !------------------------------------------------------------------ |
|---|
| 437 | !js 03/05/19 unset restriction on sign of wfx_pnd_in; mask values close to zero for future division |
|---|
| 438 | !wfx_pnd_in(:,:) = MAX( wfx_sum(:,:) + wfx_snw_sum(:,:), 0._wp ) ! available meltwater for melt ponding |
|---|
| 439 | !wfx_pnd_in(:,:) = MAX( wfx_sum(:,:) + wfx_snw_sum(:,:) , epsi10 ) * MAX( 0._wp, SIGN( 1._wp, wfx_sum(:,:) + wfx_snw_sum(:,:) - epsi10 ) ) |
|---|
| 440 | !wfx_pnd_in(:,:) = (wfx_sum(:,:) + wfx_snw_sum(:,:)) * MAX( 0._wp, SIGN( 1._wp, ABS(wfx_sum(:,:) + wfx_snw_sum(:,:)) - epsi10 ) ) |
|---|
| 441 | |
|---|
| 442 | ! MV |
|---|
| 443 | ! NB: wfx_pnd_in can be slightly negative for very small values (why?) |
|---|
| 444 | ! This can in some occasions give negative |
|---|
| 445 | ! v_ip in the first category, which then gives crazy pond |
|---|
| 446 | ! fractions and crashes the code as soon as the melt-pond |
|---|
| 447 | ! radiative coupling is activated |
|---|
| 448 | ! if we understand and remove why wfx_sum or wfx_snw could be |
|---|
| 449 | ! negative, then, we can remove the MAX |
|---|
| 450 | ! NB: I now changed to wfx_snw_sum, this may fix the problem. |
|---|
| 451 | ! We should check |
|---|
| 452 | |
|---|
| 453 | |
|---|
| 454 | ! OLI 07/2017: when we (MV & OL) first started the inclusion of melt |
|---|
| 455 | ! ponds in the model, we removed the Holland et al. (2012, see |
|---|
| 456 | ! CESM scheme above) parameterization. I put it back here, |
|---|
| 457 | ! because I think it is needed. In summary, the sinks of FW for |
|---|
| 458 | ! ponds are: 1/ Runoff through cracks/leads => depends on the |
|---|
| 459 | ! total ice area only |
|---|
| 460 | ! 2/ overflow, including Lüthje et al. (2006) limitation |
|---|
| 461 | ! (max a_ip fraction function of h_i). This is in |
|---|
| 462 | ! fact an other form of runoff that depends on the |
|---|
| 463 | ! ITD |
|---|
| 464 | ! 3/ Flushing - losses by permeability |
|---|
| 465 | ! 4/ Refreezing |
|---|
| 466 | ! 5/ Removal of ponds on thin ice |
|---|
| 467 | ! I think 1 is needed because it is different from 2. However, |
|---|
| 468 | ! test runs should/could be done, to check the sensitivity and |
|---|
| 469 | ! the real usefulness of that stuff. |
|---|
| 470 | ! Note : the Holland et al. param was wrongly wired in NEMO3.1 (using |
|---|
| 471 | ! a_i instead of at_i), which might well explain why I had a too |
|---|
| 472 | ! weak melt pond cover in my simulations (compared to MODIS, in |
|---|
| 473 | ! situ obs. and CICE simulations. |
|---|
| 474 | |
|---|
| 475 | !js 23/04/19: rewired back to a fraction with a_i |
|---|
| 476 | zrfrac(:,:,:) = rn_pnd_fracmin + ( rn_pnd_fracmax - rn_pnd_fracmin ) * aicen(:,:,:) |
|---|
| 477 | zwfx_tmp(:,:) = 0._wp |
|---|
| 478 | |
|---|
| 479 | ! MV ---> use expression from level-ice ponds, clarify what is needed |
|---|
| 480 | |
|---|
| 481 | !--- Add retained melt water to melt ponds |
|---|
| 482 | ! v_ip should never be negative, otherwise code crashes |
|---|
| 483 | ! Rq MV: as far as I saw, UM5 can create very small negative v_ip values |
|---|
| 484 | ! hence I added the max, which was not required with Prather (1 yr run) |
|---|
| 485 | ! OLI: Here I use vt_ip, so I don't know if the max is |
|---|
| 486 | ! required... |
|---|
| 487 | !zvolp(:,:) = MAX(vt_ip(:,:),0._wp) + zrfrac(:,:) * wfx_pnd_in(:,:) * z1_rhow * rdt_ice ! Total available melt water, to be distributed as melt ponds |
|---|
| 488 | ! OLI: 07/2017 Bugfix above, removed " * aice(:,:)" |
|---|
| 489 | !js 19/04/18: change zrfrac to use aicen |
|---|
| 490 | |
|---|
| 491 | zvolp(:,:) = vt_ip(:,:) |
|---|
| 492 | |
|---|
| 493 | DO jl = 1, jpl |
|---|
| 494 | ! Melt water, to be distributed as melt ponds |
|---|
| 495 | zvolp(:,:) = zvolp(:,:) - zrfrac(:,:,jl) & |
|---|
| 496 | * ( dh_i_pnd(:,:,jl)*rhoic + dh_s_pnd(:,:,jl)*rhosn ) & |
|---|
| 497 | * z1_rhow * a_i(:,:,jl) |
|---|
| 498 | END DO |
|---|
| 499 | |
|---|
| 500 | ! MV ---> use expression from level ice melt ponds (dv_mlt) |
|---|
| 501 | |
|---|
| 502 | !js 03/05/19: we truncate negative values after calculating zvolp, in a |
|---|
| 503 | ! similar manner to the subroutine ice_thd_pnd_cesm. Variation dh_i_pnd and |
|---|
| 504 | ! dh_s_pnd are negative, indicating a loss of ice or snow. But we can expect them |
|---|
| 505 | ! to be negative for some reasons. We keep this behaviour as it is, for |
|---|
| 506 | ! fluxes conservation reasons. If some dh are positive, then we remove water |
|---|
| 507 | ! indirectly from the ponds. |
|---|
| 508 | zvolp(:,:) = MAX( zvolp(:,:) , 0._wp ) |
|---|
| 509 | |
|---|
| 510 | |
|---|
| 511 | ! Fresh water flux going into the ponds |
|---|
| 512 | wfx_pnd_in(:,:) = wfx_pnd_in(:,:) + rhow * ( zvolp(:,:) - vt_ip(:,:) ) * r1_rdtice |
|---|
| 513 | |
|---|
| 514 | !--- Remove retained meltwater from surface fluxes |
|---|
| 515 | IF ( ln_pnd_fw ) THEN |
|---|
| 516 | !wfx_snw_sum(:,:) = wfx_snw_sum(:,:) * ( 1. - zrfrac(:,:) ) |
|---|
| 517 | !wfx_sum(:,:) = wfx_sum(:,:) * ( 1. - zrfrac(:,:) ) |
|---|
| 518 | |
|---|
| 519 | !js 190419: we change the code to use a_i in zrfrac. To be tested, but |
|---|
| 520 | !it should be conservative. zwfx_tmp is the flux accumulated in the |
|---|
| 521 | !ponds. wfx_pnd_in is the total surface melt fluxes. |
|---|
| 522 | zwfx_tmp(:,:) = MAX( wfx_sum(:,:) + wfx_snw_sum(:,:) , epsi10 ) & |
|---|
| 523 | & * MAX( 0._wp, SIGN( 1._wp, ABS(wfx_sum(:,:) + wfx_snw_sum(:,:)) - epsi10 ) ) |
|---|
| 524 | WHERE ( ABS(zwfx_tmp(:,:)) > epsi10 ) |
|---|
| 525 | zwfx_tmp(:,:) = wfx_pnd_in(:,:) / zwfx_tmp(:,:) |
|---|
| 526 | ELSEWHERE |
|---|
| 527 | zwfx_tmp(:,:) = 0._wp |
|---|
| 528 | ENDWHERE |
|---|
| 529 | |
|---|
| 530 | wfx_sum(:,:) = ( 1._wp - zwfx_tmp(:,:) ) * wfx_sum(:,:) |
|---|
| 531 | wfx_snw_sum(:,:) = ( 1._wp - zwfx_tmp(:,:) ) * wfx_snw_sum(:,:) |
|---|
| 532 | ENDIF |
|---|
| 533 | |
|---|
| 534 | !----------------------------------------------------------------- |
|---|
| 535 | ! Identify grid cells with ponds |
|---|
| 536 | !----------------------------------------------------------------- |
|---|
| 537 | |
|---|
| 538 | icells = 0 |
|---|
| 539 | DO jj = 1, jpj |
|---|
| 540 | DO ji = 1, jpi |
|---|
| 541 | IF ( aice(ji,jj) > epsi10 ) THEN |
|---|
| 542 | zhi = vice(ji,jj) / aice(ji,jj) |
|---|
| 543 | ELSE |
|---|
| 544 | zhi = 0._wp |
|---|
| 545 | END IF |
|---|
| 546 | |
|---|
| 547 | IF ( aice(ji,jj) > z01 .and. zhi > rn_himin .and. & |
|---|
| 548 | zvolp(ji,jj) > zmin_volp*aice(ji,jj)) THEN |
|---|
| 549 | icells = icells + 1 |
|---|
| 550 | indxi(icells) = ji |
|---|
| 551 | indxj(icells) = jj |
|---|
| 552 | ELSE ! remove ponds on thin ice, or too small ponds |
|---|
| 553 | zvolpn(ji,jj,:) = 0._wp |
|---|
| 554 | zvolp (ji,jj) = 0._wp |
|---|
| 555 | |
|---|
| 556 | a_ip(ji,jj,:) = 0._wp |
|---|
| 557 | v_ip(ji,jj,:) = 0._wp |
|---|
| 558 | a_ip_frac(ji,jj,:) = 0._wp |
|---|
| 559 | h_ip(ji,jj,:) = 0._wp |
|---|
| 560 | |
|---|
| 561 | vt_ip(ji,jj) = 0._wp |
|---|
| 562 | at_ip(ji,jj) = 0._wp |
|---|
| 563 | |
|---|
| 564 | ! IF ( ln_pnd_fw ) & !--- Give freshwater to the ocean |
|---|
| 565 | ! wfx_pnd_out(ji,jj) = wfx_pnd_out(ji,jj) + zvolp(ji,jj) * rhow * r1_rdtice |
|---|
| 566 | END IF |
|---|
| 567 | END DO ! ji |
|---|
| 568 | END DO ! jj |
|---|
| 569 | |
|---|
| 570 | |
|---|
| 571 | DO ij = 1, icells |
|---|
| 572 | |
|---|
| 573 | ji = indxi(ij) |
|---|
| 574 | jj = indxj(ij) |
|---|
| 575 | |
|---|
| 576 | !-------------------------------------------------------------- |
|---|
| 577 | ! Shrink pond due to refreezing |
|---|
| 578 | !-------------------------------------------------------------- |
|---|
| 579 | ! OLI 07/2017: Done like for empirical melt pond scheme (CESM). |
|---|
| 580 | ! Therefore, I chose to put this part of the code before the main |
|---|
| 581 | ! routines ice_thd_pnd_area/depth (contrary to the original code), |
|---|
| 582 | ! seeing the freeze-up as a global sink of |
|---|
| 583 | ! freshwater for melt ponds in the whole grid cell. If this was done |
|---|
| 584 | ! after, I would need to make an additional assumption on the shape of |
|---|
| 585 | ! melt ponds, which I don't want to do (for the CESM scheme, this |
|---|
| 586 | ! assumption was on the aspect ratio). So I remove some water due to |
|---|
| 587 | ! refreezing first (using zTavg instead of zTsfcn in each category) and |
|---|
| 588 | ! then let the FF07 routines do their job for the fractional areas and |
|---|
| 589 | ! depths of melt ponds. |
|---|
| 590 | ! The whole ice lid related stuff from FF07 was thus removed and replaced |
|---|
| 591 | ! by this. As mentionned below, this should be improved, but is much |
|---|
| 592 | ! easier to conserve heat and freshwater this way. |
|---|
| 593 | |
|---|
| 594 | ! Average surface temperature is needed to compute freeze-up at the cell |
|---|
| 595 | ! scale |
|---|
| 596 | zTavg = 0._wp |
|---|
| 597 | DO jl = 1, jpl |
|---|
| 598 | zTavg = zTavg + zTsfcn(ji,jj,jl)*aicen(ji,jj,jl) |
|---|
| 599 | END DO |
|---|
| 600 | zTavg = zTavg / aice(ji,jj) |
|---|
| 601 | |
|---|
| 602 | ! The freezing temperature for meltponds is assumed slightly below 0C, |
|---|
| 603 | ! as if meltponds had a little salt in them (hence the use of zTp). |
|---|
| 604 | ! The salt budget is not |
|---|
| 605 | ! altered for meltponds, but if it were then an actual pond freezing |
|---|
| 606 | ! temperature could be computed. |
|---|
| 607 | |
|---|
| 608 | zdTs = MAX ( zTp - zTavg, 0. ) |
|---|
| 609 | |
|---|
| 610 | zvpold = zvolp(ji,jj) |
|---|
| 611 | |
|---|
| 612 | zvolp(ji,jj) = zvolp(ji,jj) * EXP( zrexp * zdTs / zTp ) |
|---|
| 613 | |
|---|
| 614 | !--- Dump meltwater due to refreezing ( of course this is wrong |
|---|
| 615 | !--- but this parameterization is too simple ) |
|---|
| 616 | ! IF ( ln_pnd_fw ) & |
|---|
| 617 | ! wfx_pnd_out(ji,jj) = wfx_pnd_out(ji,jj) + rhow * ( zvpold - zvolp(ji,jj) ) * r1_rdtice |
|---|
| 618 | ! ! OLI 07/2017 : Bugfix above, zvpold - zvolp instead of the |
|---|
| 619 | ! ! opposite, otherwise negative contribution |
|---|
| 620 | |
|---|
| 621 | !-------------------------------------------------------------- |
|---|
| 622 | ! calculate pond area and depth |
|---|
| 623 | !-------------------------------------------------------------- |
|---|
| 624 | zdvn = 0._wp |
|---|
| 625 | CALL ice_thd_pnd_area(aice(ji,jj),vice(ji,jj), & |
|---|
| 626 | aicen(ji,jj,:), vicen(ji,jj,:), vsnon(ji,jj,:), & |
|---|
| 627 | ticen(ji,jj,:,:), salin(ji,jj,:,:), & |
|---|
| 628 | zvolpn(ji,jj,:), zvolp(ji,jj), & |
|---|
| 629 | zapondn(ji,jj,:),zhpondn(ji,jj,:), zdvn) |
|---|
| 630 | ! outputs are |
|---|
| 631 | ! - zdvn |
|---|
| 632 | ! - zvolpn |
|---|
| 633 | ! - zvolp |
|---|
| 634 | ! - zapondn |
|---|
| 635 | ! - zhpondn |
|---|
| 636 | |
|---|
| 637 | ! IF ( ln_pnd_fw ) & |
|---|
| 638 | ! wfx_pnd_out(ji,jj) = wfx_pnd_out(ji,jj) + zdvn * rhow * r1_rdtice ! update flux from ponds to ocean |
|---|
| 639 | |
|---|
| 640 | !--------------------------------------------------------------- |
|---|
| 641 | ! Update pond volume and fraction |
|---|
| 642 | !--------------------------------------------------------------- |
|---|
| 643 | DO jl = 1, jpl |
|---|
| 644 | a_ip(ji,jj,jl) = zapondn(ji,jj,jl) |
|---|
| 645 | v_ip(ji,jj,jl) = zvolpn(ji,jj,jl) |
|---|
| 646 | a_ip_frac(ji,jj,jl) = a_ip(ji,jj,jl) / MAX(aicen(ji,jj,jl), epsi10) & |
|---|
| 647 | * MAX(0._wp, SIGN(1._wp, aicen(ji,jj,jl) - epsi10)) |
|---|
| 648 | h_ip (ji,jj,jl) = zhpondn(ji,jj,jl) |
|---|
| 649 | END DO |
|---|
| 650 | END DO ! ij |
|---|
| 651 | |
|---|
| 652 | IF ( ln_pnd_fw ) THEN |
|---|
| 653 | !js 15/05/19: water going out of the ponds give a positive freshwater |
|---|
| 654 | ! flux. |
|---|
| 655 | wfx_pnd_out(:,:) = SUM(MAX(0._wp, v_ip_b(:,:,:) - v_ip(:,:,:)), DIM=3) * rhow * r1_rdtice |
|---|
| 656 | ELSE |
|---|
| 657 | wfx_pnd_out(:,:) = 0._wp |
|---|
| 658 | ENDIF |
|---|
| 659 | |
|---|
| 660 | END SUBROUTINE pnd_TOPO |
|---|
| 661 | |
|---|
| 662 | SUBROUTINE ice_thd_pnd_area(aice, vice, & |
|---|
| 663 | aicen, vicen, vsnon, ticen, & |
|---|
| 664 | salin, zvolpn, zvolp, & |
|---|
| 665 | zapondn,zhpondn,dvolp) |
|---|
| 666 | |
|---|
| 667 | !!------------------------------------------------------------------- |
|---|
| 668 | !! *** ROUTINE ice_thd_pnd_area *** |
|---|
| 669 | !! |
|---|
| 670 | !! ** Purpose : Given the total volume of meltwater, update |
|---|
| 671 | !! pond fraction (a_ip) and depth (should be volume) |
|---|
| 672 | !! |
|---|
| 673 | !! ** |
|---|
| 674 | !! |
|---|
| 675 | !!------------------------------------------------------------------ |
|---|
| 676 | |
|---|
| 677 | REAL (wp), INTENT(IN) :: & |
|---|
| 678 | aice, vice |
|---|
| 679 | |
|---|
| 680 | REAL (wp), DIMENSION(jpl), INTENT(IN) :: & |
|---|
| 681 | aicen, vicen, vsnon |
|---|
| 682 | |
|---|
| 683 | REAL (wp), DIMENSION(nlay_i,jpl), INTENT(IN) :: & |
|---|
| 684 | ticen, salin |
|---|
| 685 | |
|---|
| 686 | REAL (wp), DIMENSION(jpl), INTENT(INOUT) :: & |
|---|
| 687 | zvolpn |
|---|
| 688 | |
|---|
| 689 | REAL (wp), INTENT(INOUT) :: & |
|---|
| 690 | zvolp, dvolp |
|---|
| 691 | |
|---|
| 692 | REAL (wp), DIMENSION(jpl), INTENT(OUT) :: & |
|---|
| 693 | zapondn, zhpondn |
|---|
| 694 | |
|---|
| 695 | INTEGER :: & |
|---|
| 696 | n, ns, & |
|---|
| 697 | m_index, & |
|---|
| 698 | permflag |
|---|
| 699 | |
|---|
| 700 | REAL (wp), DIMENSION(jpl) :: & |
|---|
| 701 | hicen, & |
|---|
| 702 | hsnon, & |
|---|
| 703 | asnon, & |
|---|
| 704 | rhos, & ! OLI 07/2017 : for now this is useless, but will be useful with new snow scheme |
|---|
| 705 | alfan, & |
|---|
| 706 | betan, & |
|---|
| 707 | cum_max_vol, & |
|---|
| 708 | reduced_aicen |
|---|
| 709 | |
|---|
| 710 | REAL (wp), DIMENSION(0:jpl) :: & |
|---|
| 711 | cum_max_vol_tmp |
|---|
| 712 | |
|---|
| 713 | REAL (wp) :: & |
|---|
| 714 | hpond, & |
|---|
| 715 | drain, & |
|---|
| 716 | floe_weight, & |
|---|
| 717 | pressure_head, & |
|---|
| 718 | hsl_rel, & |
|---|
| 719 | deltah, & |
|---|
| 720 | perm, & |
|---|
| 721 | msno |
|---|
| 722 | |
|---|
| 723 | REAL (wp), parameter :: & |
|---|
| 724 | viscosity = 1.79e-3_wp, & ! kinematic water viscosity in kg/m/s |
|---|
| 725 | z0 = 0.0_wp , & |
|---|
| 726 | c1 = 1.0_wp , & |
|---|
| 727 | p4 = 0.4_wp , & |
|---|
| 728 | p6 = 0.6_wp |
|---|
| 729 | |
|---|
| 730 | !-----------| |
|---|
| 731 | ! | |
|---|
| 732 | ! |-----------| |
|---|
| 733 | !___________|___________|______________________________________sea-level |
|---|
| 734 | ! | | |
|---|
| 735 | ! | |---^--------| |
|---|
| 736 | ! | | | | |
|---|
| 737 | ! | | | |-----------| |------- |
|---|
| 738 | ! | | |alfan(n)| | | |
|---|
| 739 | ! | | | | |--------------| |
|---|
| 740 | ! | | | | | | |
|---|
| 741 | !---------------------------v------------------------------------------- |
|---|
| 742 | ! | | ^ | | | |
|---|
| 743 | ! | | | | |--------------| |
|---|
| 744 | ! | | |betan(n)| | | |
|---|
| 745 | ! | | | |-----------| |------- |
|---|
| 746 | ! | | | | |
|---|
| 747 | ! | |---v------- | |
|---|
| 748 | ! | | |
|---|
| 749 | ! |-----------| |
|---|
| 750 | ! | |
|---|
| 751 | !-----------| |
|---|
| 752 | |
|---|
| 753 | !------------------------------------------------------------------- |
|---|
| 754 | ! initialize |
|---|
| 755 | !------------------------------------------------------------------- |
|---|
| 756 | |
|---|
| 757 | rhos(:) = rhosn ! OLI 07/2017 : same has above |
|---|
| 758 | |
|---|
| 759 | DO n = 1, jpl |
|---|
| 760 | |
|---|
| 761 | zapondn(n) = z0 |
|---|
| 762 | zhpondn(n) = z0 |
|---|
| 763 | |
|---|
| 764 | !---------------------------------------- |
|---|
| 765 | ! X) compute the effective snow fraction |
|---|
| 766 | !---------------------------------------- |
|---|
| 767 | IF (aicen(n) < epsi10) THEN |
|---|
| 768 | hicen(n) = z0 |
|---|
| 769 | hsnon(n) = z0 |
|---|
| 770 | reduced_aicen(n) = z0 |
|---|
| 771 | asnon(n) = z0 !js: in CICE 5.1.2: make sense as the compiler may not initiate the variables |
|---|
| 772 | ELSE |
|---|
| 773 | hicen(n) = vicen(n) / aicen(n) |
|---|
| 774 | hsnon(n) = vsnon(n) / aicen(n) |
|---|
| 775 | reduced_aicen(n) = c1 ! n=jpl |
|---|
| 776 | |
|---|
| 777 | !js: initial code in NEMO_DEV |
|---|
| 778 | !IF (n < jpl) reduced_aicen(n) = aicen(n) & |
|---|
| 779 | ! * (-0.024_wp*hicen(n) + 0.832_wp) |
|---|
| 780 | |
|---|
| 781 | !js: from CICE 5.1.2: this limit reduced_aicen to 0.2 when hicen is too large |
|---|
| 782 | IF (n < jpl) reduced_aicen(n) = aicen(n) & |
|---|
| 783 | * max(0.2_wp,(-0.024_wp*hicen(n) + 0.832_wp)) |
|---|
| 784 | |
|---|
| 785 | asnon(n) = reduced_aicen(n) ! effective snow fraction (empirical) |
|---|
| 786 | ! MV should check whether this makes sense to have the same effective snow fraction in here |
|---|
| 787 | ! OLI: it probably doesn't |
|---|
| 788 | END IF |
|---|
| 789 | |
|---|
| 790 | ! This choice for alfa and beta ignores hydrostatic equilibium of categories. |
|---|
| 791 | ! Hydrostatic equilibium of the entire ITD is accounted for below, assuming |
|---|
| 792 | ! a surface topography implied by alfa=0.6 and beta=0.4, and rigidity across all |
|---|
| 793 | ! categories. alfa and beta partition the ITD - they are areas not thicknesses! |
|---|
| 794 | ! Multiplying by hicen, alfan and betan (below) are thus volumes per unit area. |
|---|
| 795 | ! Here, alfa = 60% of the ice area (and since hice is constant in a category, |
|---|
| 796 | ! alfan = 60% of the ice volume) in each category lies above the reference line, |
|---|
| 797 | ! and 40% below. Note: p6 is an arbitrary choice, but alfa+beta=1 is required. |
|---|
| 798 | |
|---|
| 799 | ! MV: |
|---|
| 800 | ! Note that this choice is not in the original FF07 paper and has been adopted in CICE |
|---|
| 801 | ! No reason why is explained in the doc, but I guess there is a reason. I'll try to investigate, maybe |
|---|
| 802 | |
|---|
| 803 | ! Where does that choice come from ? => OLI : Coz' Chuck Norris said so... |
|---|
| 804 | |
|---|
| 805 | alfan(n) = 0.6 * hicen(n) |
|---|
| 806 | betan(n) = 0.4 * hicen(n) |
|---|
| 807 | |
|---|
| 808 | cum_max_vol(n) = z0 |
|---|
| 809 | cum_max_vol_tmp(n) = z0 |
|---|
| 810 | |
|---|
| 811 | END DO ! jpl |
|---|
| 812 | |
|---|
| 813 | cum_max_vol_tmp(0) = z0 |
|---|
| 814 | drain = z0 |
|---|
| 815 | dvolp = z0 |
|---|
| 816 | |
|---|
| 817 | !---------------------------------------------------------- |
|---|
| 818 | ! x) Drain overflow water, update pond fraction and volume |
|---|
| 819 | !---------------------------------------------------------- |
|---|
| 820 | |
|---|
| 821 | !-------------------------------------------------------------------------- |
|---|
| 822 | ! the maximum amount of water that can be contained up to each ice category |
|---|
| 823 | !-------------------------------------------------------------------------- |
|---|
| 824 | |
|---|
| 825 | ! MV |
|---|
| 826 | ! If melt ponds are too deep to be sustainable given the ITD (OVERFLOW) |
|---|
| 827 | ! Then the excess volume cum_max_vol(jl) drains out of the system |
|---|
| 828 | ! It should be added to wfx_pnd_out |
|---|
| 829 | ! END MV |
|---|
| 830 | !js 18/04/19: XXX do something about this flux thing |
|---|
| 831 | |
|---|
| 832 | DO n = 1, jpl-1 ! last category can not hold any volume |
|---|
| 833 | |
|---|
| 834 | IF (alfan(n+1) >= alfan(n) .and. alfan(n+1) > z0) THEN |
|---|
| 835 | |
|---|
| 836 | ! total volume in level including snow |
|---|
| 837 | cum_max_vol_tmp(n) = cum_max_vol_tmp(n-1) + & |
|---|
| 838 | (alfan(n+1) - alfan(n)) * sum(reduced_aicen(1:n)) |
|---|
| 839 | |
|---|
| 840 | ! subtract snow solid volumes from lower categories in current level |
|---|
| 841 | DO ns = 1, n |
|---|
| 842 | cum_max_vol_tmp(n) = cum_max_vol_tmp(n) & |
|---|
| 843 | - rhos(ns)/rhow * & ! free air fraction that can be filled by water |
|---|
| 844 | asnon(ns) * & ! effective areal fraction of snow in that category |
|---|
| 845 | max(min(hsnon(ns)+alfan(ns)-alfan(n), alfan(n+1)-alfan(n)), z0) |
|---|
| 846 | END DO |
|---|
| 847 | |
|---|
| 848 | ELSE ! assume higher categories unoccupied |
|---|
| 849 | cum_max_vol_tmp(n) = cum_max_vol_tmp(n-1) |
|---|
| 850 | END IF |
|---|
| 851 | !IF (cum_max_vol_tmp(n) < z0) THEN |
|---|
| 852 | ! CALL abort_ice('negative melt pond volume') |
|---|
| 853 | !END IF |
|---|
| 854 | END DO |
|---|
| 855 | cum_max_vol_tmp(jpl) = cum_max_vol_tmp(jpl-1) ! last category holds no volume |
|---|
| 856 | cum_max_vol (1:jpl) = cum_max_vol_tmp(1:jpl) |
|---|
| 857 | |
|---|
| 858 | !---------------------------------------------------------------- |
|---|
| 859 | ! is there more meltwater than can be held in the floe? |
|---|
| 860 | !---------------------------------------------------------------- |
|---|
| 861 | IF (zvolp >= cum_max_vol(jpl)) THEN |
|---|
| 862 | drain = zvolp - cum_max_vol(jpl) + epsi10 |
|---|
| 863 | zvolp = zvolp - drain ! update meltwater volume available |
|---|
| 864 | dvolp = drain ! this is the drained water |
|---|
| 865 | IF (zvolp < epsi10) THEN |
|---|
| 866 | dvolp = dvolp + zvolp |
|---|
| 867 | zvolp = z0 |
|---|
| 868 | END IF |
|---|
| 869 | END IF |
|---|
| 870 | |
|---|
| 871 | ! height and area corresponding to the remaining volume |
|---|
| 872 | |
|---|
| 873 | CALL ice_thd_pnd_depth(reduced_aicen, asnon, hsnon, rhos, alfan, zvolp, cum_max_vol, hpond, m_index) |
|---|
| 874 | |
|---|
| 875 | DO n=1, m_index |
|---|
| 876 | !zhpondn(n) = hpond - alfan(n) + alfan(1) ! here oui choulde update |
|---|
| 877 | ! ! volume instead, no ? |
|---|
| 878 | zhpondn(n) = max((hpond - alfan(n) + alfan(1)), z0) !js: from CICE 5.1.2 |
|---|
| 879 | zapondn(n) = reduced_aicen(n) |
|---|
| 880 | ! in practise, pond fraction depends on the empirical snow fraction |
|---|
| 881 | ! so in turn on ice thickness |
|---|
| 882 | END DO |
|---|
| 883 | !zapond = sum(zapondn(1:m_index)) !js: from CICE 5.1.2; not in Icepack1.1.0-6-gac6195d |
|---|
| 884 | |
|---|
| 885 | !------------------------------------------------------------------------ |
|---|
| 886 | ! Drainage through brine network (permeability) |
|---|
| 887 | !------------------------------------------------------------------------ |
|---|
| 888 | !!! drainage due to ice permeability - Darcy's law |
|---|
| 889 | |
|---|
| 890 | ! sea water level |
|---|
| 891 | msno = z0 |
|---|
| 892 | DO n=1,jpl |
|---|
| 893 | msno = msno + vsnon(n) * rhos(n) |
|---|
| 894 | END DO |
|---|
| 895 | floe_weight = (msno + rhoic*vice + rau0*zvolp) / aice |
|---|
| 896 | hsl_rel = floe_weight / rau0 & |
|---|
| 897 | - ((sum(betan(:)*aicen(:))/aice) + alfan(1)) |
|---|
| 898 | |
|---|
| 899 | deltah = hpond - hsl_rel |
|---|
| 900 | pressure_head = grav * rau0 * max(deltah, z0) |
|---|
| 901 | |
|---|
| 902 | ! drain if ice is permeable |
|---|
| 903 | permflag = 0 |
|---|
| 904 | IF (pressure_head > z0) THEN |
|---|
| 905 | DO n = 1, jpl-1 |
|---|
| 906 | IF (hicen(n) /= z0) THEN |
|---|
| 907 | !IF (hicen(n) > z0) THEN !js: from CICE 5.1.2 |
|---|
| 908 | perm = 0._wp ! MV ugly dummy patch |
|---|
| 909 | CALL ice_thd_pnd_perm(ticen(:,n), salin(:,n), perm) |
|---|
| 910 | IF (perm > z0) permflag = 1 |
|---|
| 911 | |
|---|
| 912 | drain = perm*zapondn(n)*pressure_head*rdt_ice / & |
|---|
| 913 | (viscosity*hicen(n)) |
|---|
| 914 | dvolp = dvolp + min(drain, zvolp) |
|---|
| 915 | zvolp = max(zvolp - drain, z0) |
|---|
| 916 | IF (zvolp < epsi10) THEN |
|---|
| 917 | dvolp = dvolp + zvolp |
|---|
| 918 | zvolp = z0 |
|---|
| 919 | END IF |
|---|
| 920 | END IF |
|---|
| 921 | END DO |
|---|
| 922 | |
|---|
| 923 | ! adjust melt pond dimensions |
|---|
| 924 | IF (permflag > 0) THEN |
|---|
| 925 | ! recompute pond depth |
|---|
| 926 | CALL ice_thd_pnd_depth(reduced_aicen, asnon, hsnon, rhos, alfan, zvolp, cum_max_vol, hpond, m_index) |
|---|
| 927 | DO n=1, m_index |
|---|
| 928 | zhpondn(n) = hpond - alfan(n) + alfan(1) |
|---|
| 929 | zapondn(n) = reduced_aicen(n) |
|---|
| 930 | END DO |
|---|
| 931 | !zapond = sum(zapondn(1:m_index)) !js: from CICE 5.1.2; not in Icepack1.1.0-6-gac6195d |
|---|
| 932 | END IF |
|---|
| 933 | END IF ! pressure_head |
|---|
| 934 | |
|---|
| 935 | !------------------------------- |
|---|
| 936 | ! X) remove water from the snow |
|---|
| 937 | !------------------------------- |
|---|
| 938 | !------------------------------------------------------------------------ |
|---|
| 939 | ! total melt pond volume in category does not include snow volume |
|---|
| 940 | ! snow in melt ponds is not melted |
|---|
| 941 | !------------------------------------------------------------------------ |
|---|
| 942 | |
|---|
| 943 | ! Calculate pond volume for lower categories |
|---|
| 944 | DO n=1,m_index-1 |
|---|
| 945 | zvolpn(n) = zapondn(n) * zhpondn(n) & ! what is not in the snow |
|---|
| 946 | - (rhos(n)/rhow) * asnon(n) * min(hsnon(n), zhpondn(n)) |
|---|
| 947 | END DO |
|---|
| 948 | |
|---|
| 949 | ! Calculate pond volume for highest category = remaining pond volume |
|---|
| 950 | |
|---|
| 951 | ! The following is completely unclear to Martin at least |
|---|
| 952 | ! Could we redefine properly and recode in a more readable way ? |
|---|
| 953 | |
|---|
| 954 | ! m_index = last category with melt pond |
|---|
| 955 | |
|---|
| 956 | IF (m_index == 1) zvolpn(m_index) = zvolp ! volume of mw in 1st category is the total volume of melt water |
|---|
| 957 | |
|---|
| 958 | IF (m_index > 1) THEN |
|---|
| 959 | IF (zvolp > sum(zvolpn(1:m_index-1))) THEN |
|---|
| 960 | zvolpn(m_index) = zvolp - sum(zvolpn(1:m_index-1)) |
|---|
| 961 | ELSE |
|---|
| 962 | zvolpn(m_index) = z0 |
|---|
| 963 | zhpondn(m_index) = z0 |
|---|
| 964 | zapondn(m_index) = z0 |
|---|
| 965 | ! If remaining pond volume is negative reduce pond volume of |
|---|
| 966 | ! lower category |
|---|
| 967 | IF (zvolp+epsi10 < sum(zvolpn(1:m_index-1))) & |
|---|
| 968 | zvolpn(m_index-1) = zvolpn(m_index-1) - sum(zvolpn(1:m_index-1)) + zvolp |
|---|
| 969 | END IF |
|---|
| 970 | END IF |
|---|
| 971 | |
|---|
| 972 | DO n=1,m_index |
|---|
| 973 | IF (zapondn(n) > epsi10) THEN |
|---|
| 974 | zhpondn(n) = zvolpn(n) / zapondn(n) |
|---|
| 975 | ELSE |
|---|
| 976 | dvolp = dvolp + zvolpn(n) |
|---|
| 977 | zhpondn(n) = z0 |
|---|
| 978 | zvolpn(n) = z0 |
|---|
| 979 | zapondn(n) = z0 |
|---|
| 980 | END IF |
|---|
| 981 | END DO |
|---|
| 982 | DO n = m_index+1, jpl |
|---|
| 983 | zhpondn(n) = z0 |
|---|
| 984 | zapondn(n) = z0 |
|---|
| 985 | zvolpn (n) = z0 |
|---|
| 986 | END DO |
|---|
| 987 | |
|---|
| 988 | END SUBROUTINE ice_thd_pnd_area |
|---|
| 989 | |
|---|
| 990 | |
|---|
| 991 | SUBROUTINE ice_thd_pnd_depth(aicen, asnon, hsnon, rhos, alfan, zvolp, cum_max_vol, hpond, m_index) |
|---|
| 992 | !!------------------------------------------------------------------- |
|---|
| 993 | !! *** ROUTINE ice_thd_pnd_depth *** |
|---|
| 994 | !! |
|---|
| 995 | !! ** Purpose : Compute melt pond depth |
|---|
| 996 | !!------------------------------------------------------------------- |
|---|
| 997 | |
|---|
| 998 | REAL (wp), DIMENSION(jpl), INTENT(IN) :: & |
|---|
| 999 | aicen, & |
|---|
| 1000 | asnon, & |
|---|
| 1001 | hsnon, & |
|---|
| 1002 | rhos, & |
|---|
| 1003 | alfan, & |
|---|
| 1004 | cum_max_vol |
|---|
| 1005 | |
|---|
| 1006 | REAL (wp), INTENT(IN) :: & |
|---|
| 1007 | zvolp |
|---|
| 1008 | |
|---|
| 1009 | REAL (wp), INTENT(OUT) :: & |
|---|
| 1010 | hpond |
|---|
| 1011 | |
|---|
| 1012 | INTEGER, INTENT(OUT) :: & |
|---|
| 1013 | m_index |
|---|
| 1014 | |
|---|
| 1015 | INTEGER :: n, ns |
|---|
| 1016 | |
|---|
| 1017 | REAL (wp), DIMENSION(0:jpl+1) :: & |
|---|
| 1018 | hitl, & |
|---|
| 1019 | aicetl |
|---|
| 1020 | |
|---|
| 1021 | REAL (wp) :: & |
|---|
| 1022 | rem_vol, & |
|---|
| 1023 | area, & |
|---|
| 1024 | vol, & |
|---|
| 1025 | tmp, & |
|---|
| 1026 | z0 = 0.0_wp |
|---|
| 1027 | |
|---|
| 1028 | !---------------------------------------------------------------- |
|---|
| 1029 | ! hpond is zero if zvolp is zero - have we fully drained? |
|---|
| 1030 | !---------------------------------------------------------------- |
|---|
| 1031 | |
|---|
| 1032 | IF (zvolp < epsi10) THEN |
|---|
| 1033 | hpond = z0 |
|---|
| 1034 | m_index = 0 |
|---|
| 1035 | ELSE |
|---|
| 1036 | |
|---|
| 1037 | !---------------------------------------------------------------- |
|---|
| 1038 | ! Calculate the category where water fills up to |
|---|
| 1039 | !---------------------------------------------------------------- |
|---|
| 1040 | |
|---|
| 1041 | !----------| |
|---|
| 1042 | ! | |
|---|
| 1043 | ! | |
|---|
| 1044 | ! |----------| -- -- |
|---|
| 1045 | !__________|__________|_________________________________________ ^ |
|---|
| 1046 | ! | | rem_vol ^ | Semi-filled |
|---|
| 1047 | ! | |----------|-- -- -- - ---|-- ---- -- -- --v layer |
|---|
| 1048 | ! | | | | |
|---|
| 1049 | ! | | | |hpond |
|---|
| 1050 | ! | | |----------| | |------- |
|---|
| 1051 | ! | | | | | | |
|---|
| 1052 | ! | | | |---v-----| |
|---|
| 1053 | ! | | m_index | | | |
|---|
| 1054 | !------------------------------------------------------------- |
|---|
| 1055 | |
|---|
| 1056 | m_index = 0 ! 1:m_index categories have water in them |
|---|
| 1057 | DO n = 1, jpl |
|---|
| 1058 | IF (zvolp <= cum_max_vol(n)) THEN |
|---|
| 1059 | m_index = n |
|---|
| 1060 | IF (n == 1) THEN |
|---|
| 1061 | rem_vol = zvolp |
|---|
| 1062 | ELSE |
|---|
| 1063 | rem_vol = zvolp - cum_max_vol(n-1) |
|---|
| 1064 | END IF |
|---|
| 1065 | exit ! to break out of the loop |
|---|
| 1066 | END IF |
|---|
| 1067 | END DO |
|---|
| 1068 | m_index = min(jpl-1, m_index) |
|---|
| 1069 | |
|---|
| 1070 | !---------------------------------------------------------------- |
|---|
| 1071 | ! semi-filled layer may have m_index different snow in it |
|---|
| 1072 | !---------------------------------------------------------------- |
|---|
| 1073 | |
|---|
| 1074 | !----------------------------------------------------------- ^ |
|---|
| 1075 | ! | alfan(m_index+1) |
|---|
| 1076 | ! | |
|---|
| 1077 | !hitl(3)--> |----------| | |
|---|
| 1078 | !hitl(2)--> |------------| * * * * *| | |
|---|
| 1079 | !hitl(1)--> |----------|* * * * * * |* * * * * | | |
|---|
| 1080 | !hitl(0)-->------------------------------------------------- | ^ |
|---|
| 1081 | ! various snow from lower categories | |alfa(m_index) |
|---|
| 1082 | |
|---|
| 1083 | ! hitl - heights of the snow layers from thinner and current categories |
|---|
| 1084 | ! aicetl - area of each snow depth in this layer |
|---|
| 1085 | |
|---|
| 1086 | hitl(:) = z0 |
|---|
| 1087 | aicetl(:) = z0 |
|---|
| 1088 | DO n = 1, m_index |
|---|
| 1089 | hitl(n) = max(min(hsnon(n) + alfan(n) - alfan(m_index), & |
|---|
| 1090 | alfan(m_index+1) - alfan(m_index)), z0) |
|---|
| 1091 | aicetl(n) = asnon(n) |
|---|
| 1092 | |
|---|
| 1093 | aicetl(0) = aicetl(0) + (aicen(n) - asnon(n)) |
|---|
| 1094 | END DO |
|---|
| 1095 | |
|---|
| 1096 | hitl(m_index+1) = alfan(m_index+1) - alfan(m_index) |
|---|
| 1097 | aicetl(m_index+1) = z0 |
|---|
| 1098 | |
|---|
| 1099 | !---------------------------------------------------------------- |
|---|
| 1100 | ! reorder array according to hitl |
|---|
| 1101 | ! snow heights not necessarily in height order |
|---|
| 1102 | !---------------------------------------------------------------- |
|---|
| 1103 | |
|---|
| 1104 | DO ns = 1, m_index+1 |
|---|
| 1105 | DO n = 0, m_index - ns + 1 |
|---|
| 1106 | IF (hitl(n) > hitl(n+1)) THEN ! swap order |
|---|
| 1107 | tmp = hitl(n) |
|---|
| 1108 | hitl(n) = hitl(n+1) |
|---|
| 1109 | hitl(n+1) = tmp |
|---|
| 1110 | tmp = aicetl(n) |
|---|
| 1111 | aicetl(n) = aicetl(n+1) |
|---|
| 1112 | aicetl(n+1) = tmp |
|---|
| 1113 | END IF |
|---|
| 1114 | END DO |
|---|
| 1115 | END DO |
|---|
| 1116 | |
|---|
| 1117 | !---------------------------------------------------------------- |
|---|
| 1118 | ! divide semi-filled layer into set of sublayers each vertically homogenous |
|---|
| 1119 | !---------------------------------------------------------------- |
|---|
| 1120 | |
|---|
| 1121 | !hitl(3)---------------------------------------------------------------- |
|---|
| 1122 | ! | * * * * * * * * |
|---|
| 1123 | ! |* * * * * * * * * |
|---|
| 1124 | !hitl(2)---------------------------------------------------------------- |
|---|
| 1125 | ! | * * * * * * * * | * * * * * * * * |
|---|
| 1126 | ! |* * * * * * * * * |* * * * * * * * * |
|---|
| 1127 | !hitl(1)---------------------------------------------------------------- |
|---|
| 1128 | ! | * * * * * * * * | * * * * * * * * | * * * * * * * * |
|---|
| 1129 | ! |* * * * * * * * * |* * * * * * * * * |* * * * * * * * * |
|---|
| 1130 | !hitl(0)---------------------------------------------------------------- |
|---|
| 1131 | ! aicetl(0) aicetl(1) aicetl(2) aicetl(3) |
|---|
| 1132 | |
|---|
| 1133 | ! move up over layers incrementing volume |
|---|
| 1134 | DO n = 1, m_index+1 |
|---|
| 1135 | |
|---|
| 1136 | area = sum(aicetl(:)) - & ! total area of sub-layer |
|---|
| 1137 | (rhos(n)/rau0) * sum(aicetl(n:jpl+1)) ! area of sub-layer occupied by snow |
|---|
| 1138 | |
|---|
| 1139 | vol = (hitl(n) - hitl(n-1)) * area ! thickness of sub-layer times area |
|---|
| 1140 | |
|---|
| 1141 | IF (vol >= rem_vol) THEN ! have reached the sub-layer with the depth within |
|---|
| 1142 | hpond = rem_vol / area + hitl(n-1) + alfan(m_index) - alfan(1) |
|---|
| 1143 | |
|---|
| 1144 | exit |
|---|
| 1145 | ELSE ! still in sub-layer below the sub-layer with the depth |
|---|
| 1146 | rem_vol = rem_vol - vol |
|---|
| 1147 | END IF |
|---|
| 1148 | |
|---|
| 1149 | END DO |
|---|
| 1150 | |
|---|
| 1151 | END IF |
|---|
| 1152 | |
|---|
| 1153 | END SUBROUTINE ice_thd_pnd_depth |
|---|
| 1154 | |
|---|
| 1155 | |
|---|
| 1156 | SUBROUTINE ice_thd_pnd_perm(ticen, salin, perm) |
|---|
| 1157 | !!------------------------------------------------------------------- |
|---|
| 1158 | !! *** ROUTINE ice_thd_pnd_perm *** |
|---|
| 1159 | !! |
|---|
| 1160 | !! ** Purpose : Determine the liquid fraction of brine in the ice |
|---|
| 1161 | !! and its permeability |
|---|
| 1162 | !!------------------------------------------------------------------- |
|---|
| 1163 | |
|---|
| 1164 | REAL (wp), DIMENSION(nlay_i), INTENT(IN) :: & |
|---|
| 1165 | ticen, & ! internal ice temperature (K) |
|---|
| 1166 | salin ! salinity (ppt) !js: ppt according to cice |
|---|
| 1167 | |
|---|
| 1168 | REAL (wp), INTENT(OUT) :: & |
|---|
| 1169 | perm ! permeability |
|---|
| 1170 | |
|---|
| 1171 | REAL (wp) :: & |
|---|
| 1172 | Sbr ! brine salinity |
|---|
| 1173 | |
|---|
| 1174 | REAL (wp), DIMENSION(nlay_i) :: & |
|---|
| 1175 | Tin, & ! ice temperature |
|---|
| 1176 | phi ! liquid fraction |
|---|
| 1177 | |
|---|
| 1178 | INTEGER :: k |
|---|
| 1179 | |
|---|
| 1180 | !----------------------------------------------------------------- |
|---|
| 1181 | ! Compute ice temperatures from enthalpies using quadratic formula |
|---|
| 1182 | !----------------------------------------------------------------- |
|---|
| 1183 | |
|---|
| 1184 | DO k = 1,nlay_i |
|---|
| 1185 | Tin(k) = ticen(k) - rt0 !js: from K to degC |
|---|
| 1186 | END DO |
|---|
| 1187 | |
|---|
| 1188 | !----------------------------------------------------------------- |
|---|
| 1189 | ! brine salinity and liquid fraction |
|---|
| 1190 | !----------------------------------------------------------------- |
|---|
| 1191 | |
|---|
| 1192 | DO k = 1, nlay_i |
|---|
| 1193 | |
|---|
| 1194 | Sbr = - Tin(k) / rTmlt ! Consistent expression with SI3 (linear liquidus) |
|---|
| 1195 | ! Best expression to date is that one |
|---|
| 1196 | ! Sbr = - 18.7 * Tin(k) − 0.519 * Tin(k)**2 − 0.00535 * Tin(k) ***3 |
|---|
| 1197 | phi(k) = salin(k) / Sbr |
|---|
| 1198 | |
|---|
| 1199 | END DO |
|---|
| 1200 | |
|---|
| 1201 | !----------------------------------------------------------------- |
|---|
| 1202 | ! permeability |
|---|
| 1203 | !----------------------------------------------------------------- |
|---|
| 1204 | |
|---|
| 1205 | perm = 3.0e-08_wp * (minval(phi))**3 ! Golden et al. (2007) |
|---|
| 1206 | |
|---|
| 1207 | END SUBROUTINE ice_thd_pnd_perm |
|---|
| 1208 | |
|---|
| 1209 | |
|---|
| 1210 | !---------------------------------------------------------------------------------------------------------------------- |
|---|
| 1211 | |
|---|
| 1212 | SUBROUTINE ice_thd_pnd_init |
|---|
| 1213 | !!------------------------------------------------------------------- |
|---|
| 1214 | !! *** ROUTINE ice_thd_pnd_init *** |
|---|
| 1215 | !! |
|---|
| 1216 | !! ** Purpose : Physical constants and parameters linked to melt ponds |
|---|
| 1217 | !! over sea ice |
|---|
| 1218 | !! |
|---|
| 1219 | !! ** Method : Read the namthd_pnd namelist and check the melt pond |
|---|
| 1220 | !! parameter values called at the first timestep (nit000) |
|---|
| 1221 | !! |
|---|
| 1222 | !! ** input : Namelist namthd_pnd |
|---|
| 1223 | !!------------------------------------------------------------------- |
|---|
| 1224 | INTEGER :: ios, ioptio ! Local integer |
|---|
| 1225 | !! |
|---|
| 1226 | NAMELIST/namthd_pnd/ ln_pnd, ln_pnd_LEV , rn_apnd_min, rn_apnd_max, & |
|---|
| 1227 | & ln_pnd_CST , rn_apnd, rn_hpnd, & |
|---|
| 1228 | & ln_pnd_TOPO , & |
|---|
| 1229 | & ln_pnd_lids, ln_pnd_alb |
|---|
| 1230 | !!------------------------------------------------------------------- |
|---|
| 1231 | ! |
|---|
| 1232 | REWIND( numnam_ice_ref ) ! Namelist namthd_pnd in reference namelist : Melt Ponds |
|---|
| 1233 | READ ( numnam_ice_ref, namthd_pnd, IOSTAT = ios, ERR = 901) |
|---|
| 1234 | 901 IF( ios /= 0 ) CALL ctl_nam ( ios , 'namthd_pnd in reference namelist' ) |
|---|
| 1235 | REWIND( numnam_ice_cfg ) ! Namelist namthd_pnd in configuration namelist : Melt Ponds |
|---|
| 1236 | READ ( numnam_ice_cfg, namthd_pnd, IOSTAT = ios, ERR = 902 ) |
|---|
| 1237 | 902 IF( ios > 0 ) CALL ctl_nam ( ios , 'namthd_pnd in configuration namelist' ) |
|---|
| 1238 | IF(lwm) WRITE ( numoni, namthd_pnd ) |
|---|
| 1239 | ! |
|---|
| 1240 | IF(lwp) THEN ! control print |
|---|
| 1241 | WRITE(numout,*) |
|---|
| 1242 | WRITE(numout,*) 'ice_thd_pnd_init: ice parameters for melt ponds' |
|---|
| 1243 | WRITE(numout,*) '~~~~~~~~~~~~~~~~' |
|---|
| 1244 | WRITE(numout,*) ' Namelist namicethd_pnd:' |
|---|
| 1245 | WRITE(numout,*) ' Melt ponds activated or not ln_pnd = ', ln_pnd |
|---|
| 1246 | WRITE(numout,*) ' Topographic melt pond scheme ln_pnd_TOPO = ', ln_pnd_TOPO |
|---|
| 1247 | WRITE(numout,*) ' Level ice melt pond scheme ln_pnd_LEV = ', ln_pnd_LEV |
|---|
| 1248 | WRITE(numout,*) ' Minimum ice fraction that contributes to melt ponds rn_apnd_min = ', rn_apnd_min |
|---|
| 1249 | WRITE(numout,*) ' Maximum ice fraction that contributes to melt ponds rn_apnd_max = ', rn_apnd_max |
|---|
| 1250 | WRITE(numout,*) ' Constant ice melt pond scheme ln_pnd_CST = ', ln_pnd_CST |
|---|
| 1251 | WRITE(numout,*) ' Prescribed pond fraction rn_apnd = ', rn_apnd |
|---|
| 1252 | WRITE(numout,*) ' Prescribed pond depth rn_hpnd = ', rn_hpnd |
|---|
| 1253 | WRITE(numout,*) ' Frozen lids on top of melt ponds ln_pnd_lids = ', ln_pnd_lids |
|---|
| 1254 | WRITE(numout,*) ' Melt ponds affect albedo or not ln_pnd_alb = ', ln_pnd_alb |
|---|
| 1255 | ENDIF |
|---|
| 1256 | ! |
|---|
| 1257 | ! !== set the choice of ice pond scheme ==! |
|---|
| 1258 | ioptio = 0 |
|---|
| 1259 | IF( .NOT.ln_pnd ) THEN ; ioptio = ioptio + 1 ; nice_pnd = np_pndNO ; ENDIF |
|---|
| 1260 | IF( ln_pnd_CST ) THEN ; ioptio = ioptio + 1 ; nice_pnd = np_pndCST ; ENDIF |
|---|
| 1261 | IF( ln_pnd_LEV ) THEN ; ioptio = ioptio + 1 ; nice_pnd = np_pndLEV ; ENDIF |
|---|
| 1262 | IF( ioptio /= 1 ) & |
|---|
| 1263 | & CALL ctl_stop( 'ice_thd_pnd_init: choose either none (ln_pnd=F) or only one pond scheme (ln_pnd_LEV or ln_pnd_CST)' ) |
|---|
| 1264 | ! |
|---|
| 1265 | SELECT CASE( nice_pnd ) |
|---|
| 1266 | CASE( np_pndNO ) |
|---|
| 1267 | IF( ln_pnd_alb ) THEN ; ln_pnd_alb = .FALSE. ; CALL ctl_warn( 'ln_pnd_alb=false when no ponds' ) ; ENDIF |
|---|
| 1268 | IF( ln_pnd_lids ) THEN ; ln_pnd_lids = .FALSE. ; CALL ctl_warn( 'ln_pnd_lids=false when no ponds' ) ; ENDIF |
|---|
| 1269 | CASE( np_pndCST ) |
|---|
| 1270 | IF( ln_pnd_lids ) THEN ; ln_pnd_lids = .FALSE. ; CALL ctl_warn( 'ln_pnd_lids=false when constant ponds' ) ; ENDIF |
|---|
| 1271 | END SELECT |
|---|
| 1272 | ! |
|---|
| 1273 | END SUBROUTINE ice_thd_pnd_init |
|---|
| 1274 | |
|---|
| 1275 | #else |
|---|
| 1276 | !!---------------------------------------------------------------------- |
|---|
| 1277 | !! Default option Empty module NO SI3 sea-ice model |
|---|
| 1278 | !!---------------------------------------------------------------------- |
|---|
| 1279 | #endif |
|---|
| 1280 | |
|---|
| 1281 | !!====================================================================== |
|---|
| 1282 | END MODULE icethd_pnd |
|---|
