[152] | 1 | MODULE albedo |
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| 2 | !!====================================================================== |
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| 3 | !! *** MODULE albedo *** |
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| 4 | !! Ocean forcing: bulk thermohaline forcing of the ocean (or ice) |
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| 5 | !!===================================================================== |
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[888] | 6 | !! History : 8.0 ! 01-04 (LIM 1.0) |
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| 7 | !! 8.5 ! 03-07 (C. Ethe, G. Madec) Optimization (old name:shine) |
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| 8 | !! 9.0 ! 04-11 (C. Talandier) add albedo_init |
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| 9 | !! - ! 01-06 (M. Vancoppenolle) LIM 3.0 |
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| 10 | !! - ! 06-08 (G. Madec) cleaning for surface module |
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[152] | 11 | !!---------------------------------------------------------------------- |
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[888] | 12 | !! albedo_ice : albedo for ice (clear and overcast skies) |
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| 13 | !! albedo_oce : albedo for ocean (clear and overcast skies) |
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| 14 | !! albedo_init : initialisation of albedo computation |
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[152] | 15 | !!---------------------------------------------------------------------- |
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| 16 | USE phycst ! physical constants |
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[888] | 17 | USE in_out_manager ! I/O manager |
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[152] | 18 | |
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| 19 | IMPLICIT NONE |
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| 20 | PRIVATE |
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| 21 | |
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[888] | 22 | PUBLIC albedo_ice ! routine called sbcice_lim.F90 |
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| 23 | PUBLIC albedo_oce ! routine called by ??? |
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[165] | 24 | |
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[888] | 25 | INTEGER :: albd_init = 0 !: control flag for initialization |
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| 26 | REAL(wp) :: zzero = 0.e0 ! constant values |
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| 27 | REAL(wp) :: zone = 1.e0 ! " " |
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[152] | 28 | |
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[888] | 29 | REAL(wp) :: c1 = 0.05 ! constants values |
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| 30 | REAL(wp) :: c2 = 0.10 ! " " |
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| 31 | REAL(wp) :: rmue = 0.40 ! cosine of local solar altitude |
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| 32 | |
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| 33 | !!* namelist namalb |
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[152] | 34 | REAL(wp) :: & |
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[892] | 35 | cgren = 0.06 , & ! cloudiness effect on snow or ice albedo (Grenfell & Perovich, 1984) |
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[833] | 36 | #if defined key_lim3 |
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| 37 | albice = 0.53 , & ! albedo of melting ice in the arctic and antarctic (Shine & Hendersson-Sellers) |
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| 38 | #else |
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[719] | 39 | albice = 0.50 , & ! albedo of melting ice in the arctic and antarctic (Shine & Hendersson-Sellers) |
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[833] | 40 | #endif |
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[152] | 41 | alphd = 0.80 , & ! coefficients for linear interpolation used to compute |
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| 42 | alphdi = 0.72 , & ! albedo between two extremes values (Pyane, 1972) |
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[888] | 43 | alphc = 0.65 |
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[152] | 44 | |
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| 45 | !!---------------------------------------------------------------------- |
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[888] | 46 | !! OPA 9.0 , LOCEAN-IPSL (2006) |
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| 47 | !! $Id$ |
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| 48 | !! Software governed by the CeCILL licence (modipsl/doc/NEMO_CeCILL.txt) |
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[152] | 49 | !!---------------------------------------------------------------------- |
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| 50 | |
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| 51 | CONTAINS |
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| 52 | |
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[888] | 53 | SUBROUTINE albedo_ice( pt_ice, ph_ice, ph_snw, pa_ice_cs, pa_ice_os ) |
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[152] | 54 | !!---------------------------------------------------------------------- |
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[888] | 55 | !! *** ROUTINE albedo_ice *** |
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[152] | 56 | !! |
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| 57 | !! ** Purpose : Computation of the albedo of the snow/ice system |
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[888] | 58 | !! as well as the ocean one |
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[152] | 59 | !! |
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| 60 | !! ** Method : - Computation of the albedo of snow or ice (choose the |
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[888] | 61 | !! rignt one by a large number of tests |
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[152] | 62 | !! - Computation of the albedo of the ocean |
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| 63 | !! |
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[888] | 64 | !! References : Shine and Hendersson-Sellers 1985, JGR, 90(D1), 2243-2250. |
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| 65 | !!---------------------------------------------------------------------- |
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| 66 | REAL(wp), INTENT(in ), DIMENSION(:,:,:) :: pt_ice ! ice surface temperature |
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| 67 | REAL(wp), INTENT(in ), DIMENSION(:,:,:) :: ph_ice ! sea-ice thickness |
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| 68 | REAL(wp), INTENT(in ), DIMENSION(:,:,:) :: ph_snw ! snow thickness |
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| 69 | REAL(wp), INTENT( out), DIMENSION(:,:,:) :: pa_ice_cs ! albedo of ice under clear sky |
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| 70 | REAL(wp), INTENT( out), DIMENSION(:,:,:) :: pa_ice_os ! albedo of ice under overcast sky |
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[719] | 71 | !! |
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[888] | 72 | INTEGER :: ji, jj, jl ! dummy loop indices |
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| 73 | INTEGER :: ijpl ! number of ice categories (3rd dim of ice input arrays) |
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| 74 | REAL(wp) :: zalbpsnm ! albedo of ice under clear sky when snow is melting |
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| 75 | REAL(wp) :: zalbpsnf ! albedo of ice under clear sky when snow is freezing |
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| 76 | REAL(wp) :: zalbpsn ! albedo of snow/ice system when ice is coverd by snow |
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| 77 | REAL(wp) :: zalbpic ! albedo of snow/ice system when ice is free of snow |
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| 78 | REAL(wp) :: zithsn ! = 1 for hsn >= 0 ( ice is cov. by snow ) ; = 0 otherwise (ice is free of snow) |
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| 79 | REAL(wp) :: zitmlsn ! = 1 freezinz snow (pt_ice >=rt0_snow) ; = 0 melting snow (pt_ice<rt0_snow) |
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| 80 | REAL(wp) :: zihsc1 ! = 1 hsn <= c1 ; = 0 hsn > c1 |
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| 81 | REAL(wp) :: zihsc2 ! = 1 hsn >= c2 ; = 0 hsn < c2 |
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| 82 | !! |
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| 83 | LOGICAL , DIMENSION(jpi,jpj,SIZE(pt_ice,3)) :: llmask |
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| 84 | REAL(wp), DIMENSION(jpi,jpj,SIZE(pt_ice,3)) :: zalbfz ! = alphdi for freezing ice ; = albice for melting ice |
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| 85 | REAL(wp), DIMENSION(jpi,jpj,SIZE(pt_ice,3)) :: zficeth ! function of ice thickness |
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[152] | 86 | !!--------------------------------------------------------------------- |
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| 87 | |
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[888] | 88 | ijpl = SIZE( pt_ice, 3 ) ! number of ice categories |
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[165] | 89 | |
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[888] | 90 | IF( albd_init == 0 ) CALL albedo_init ! initialization |
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| 91 | |
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| 92 | !--------------------------- |
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[152] | 93 | ! Computation of zficeth |
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[888] | 94 | !--------------------------- |
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| 95 | llmask = ( ph_snw == 0.e0 ) .AND. ( pt_ice >= rt0_ice ) |
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| 96 | ! ice free of snow and melts |
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| 97 | WHERE( llmask ) ; zalbfz = albice |
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| 98 | ELSEWHERE ; zalbfz = alphdi |
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[152] | 99 | END WHERE |
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[888] | 100 | |
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| 101 | DO jl = 1, ijpl |
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[833] | 102 | DO jj = 1, jpj |
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| 103 | DO ji = 1, jpi |
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[888] | 104 | IF( ph_ice(ji,jj,jl) > 1.5 ) THEN |
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[833] | 105 | zficeth(ji,jj,jl) = zalbfz(ji,jj,jl) |
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[888] | 106 | ELSEIF( ph_ice(ji,jj,jl) > 1.0 .AND. ph_ice(ji,jj,jl) <= 1.5 ) THEN |
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| 107 | zficeth(ji,jj,jl) = 0.472 + 2.0 * ( zalbfz(ji,jj,jl) - 0.472 ) * ( ph_ice(ji,jj,jl) - 1.0 ) |
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| 108 | ELSEIF( ph_ice(ji,jj,jl) > 0.05 .AND. ph_ice(ji,jj,jl) <= 1.0 ) THEN |
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| 109 | zficeth(ji,jj,jl) = 0.2467 + 0.7049 * ph_ice(ji,jj,jl) & |
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| 110 | & - 0.8608 * ph_ice(ji,jj,jl) * ph_ice(ji,jj,jl) & |
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| 111 | & + 0.3812 * ph_ice(ji,jj,jl) * ph_ice(ji,jj,jl) * ph_ice (ji,jj,jl) |
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[833] | 112 | ELSE |
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[888] | 113 | zficeth(ji,jj,jl) = 0.1 + 3.6 * ph_ice(ji,jj,jl) |
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[833] | 114 | ENDIF |
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| 115 | END DO |
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| 116 | END DO |
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| 117 | END DO |
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[152] | 118 | |
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| 119 | !----------------------------------------------- |
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| 120 | ! Computation of the snow/ice albedo system |
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| 121 | !-------------------------- --------------------- |
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| 122 | |
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| 123 | ! Albedo of snow-ice for clear sky. |
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| 124 | !----------------------------------------------- |
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[888] | 125 | DO jl = 1, ijpl |
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[833] | 126 | DO jj = 1, jpj |
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| 127 | DO ji = 1, jpi |
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| 128 | ! Case of ice covered by snow. |
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[888] | 129 | ! ! freezing snow |
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| 130 | zihsc1 = 1.0 - MAX( zzero , SIGN( zone , - ( ph_snw(ji,jj,jl) - c1 ) ) ) |
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| 131 | zalbpsnf = ( 1.0 - zihsc1 ) * ( zficeth(ji,jj,jl) & |
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| 132 | & + ph_snw(ji,jj,jl) * ( alphd - zficeth(ji,jj,jl) ) / c1 ) & |
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| 133 | & + zihsc1 * alphd |
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| 134 | ! ! melting snow |
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| 135 | zihsc2 = MAX( zzero , SIGN( zone , ph_snw(ji,jj,jl) - c2 ) ) |
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| 136 | zalbpsnm = ( 1.0 - zihsc2 ) * ( albice + ph_snw(ji,jj,jl) * ( alphc - albice ) / c2 ) & |
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| 137 | & + zihsc2 * alphc |
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| 138 | ! |
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| 139 | zitmlsn = MAX( zzero , SIGN( zone , pt_ice(ji,jj,jl) - rt0_snow ) ) |
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| 140 | zalbpsn = zitmlsn * zalbpsnm + ( 1.0 - zitmlsn ) * zalbpsnf |
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[833] | 141 | |
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| 142 | ! Case of ice free of snow. |
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[888] | 143 | zalbpic = zficeth(ji,jj,jl) |
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[833] | 144 | |
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| 145 | ! albedo of the system |
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[888] | 146 | zithsn = 1.0 - MAX( zzero , SIGN( zone , - ph_snw(ji,jj,jl) ) ) |
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| 147 | pa_ice_cs(ji,jj,jl) = zithsn * zalbpsn + ( 1.0 - zithsn ) * zalbpic |
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[833] | 148 | END DO |
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| 149 | END DO |
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| 150 | END DO |
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| 151 | |
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| 152 | ! Albedo of snow-ice for overcast sky. |
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| 153 | !---------------------------------------------- |
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[888] | 154 | pa_ice_os(:,:,:) = pa_ice_cs(:,:,:) + cgren ! Oberhuber correction |
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| 155 | ! |
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| 156 | END SUBROUTINE albedo_ice |
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[833] | 157 | |
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| 158 | |
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[888] | 159 | SUBROUTINE albedo_oce( pa_oce_os , pa_oce_cs ) |
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[152] | 160 | !!---------------------------------------------------------------------- |
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[888] | 161 | !! *** ROUTINE albedo_oce *** |
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[152] | 162 | !! |
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[888] | 163 | !! ** Purpose : Computation of the albedo of the ocean |
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[152] | 164 | !! |
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[888] | 165 | !! ** Method : .... |
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| 166 | !!---------------------------------------------------------------------- |
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| 167 | REAL(wp), DIMENSION(jpi,jpj), INTENT(out) :: pa_oce_os ! albedo of ocean under overcast sky |
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| 168 | REAL(wp), DIMENSION(jpi,jpj), INTENT(out) :: pa_oce_cs ! albedo of ocean under clear sky |
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[152] | 169 | !! |
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[888] | 170 | REAL(wp) :: zcoef ! temporary scalar |
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[152] | 171 | !!---------------------------------------------------------------------- |
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[888] | 172 | ! |
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| 173 | zcoef = 0.05 / ( 1.1 * rmue**1.4 + 0.15 ) ! Parameterization of Briegled and Ramanathan, 1982 |
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| 174 | pa_oce_cs(:,:) = zcoef |
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| 175 | pa_oce_os(:,:) = 0.06 ! Parameterization of Kondratyev, 1969 and Payne, 1972 |
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| 176 | ! |
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| 177 | END SUBROUTINE albedo_oce |
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[152] | 178 | |
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| 179 | |
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[165] | 180 | SUBROUTINE albedo_init |
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| 181 | !!---------------------------------------------------------------------- |
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| 182 | !! *** ROUTINE albedo_init *** |
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| 183 | !! |
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| 184 | !! ** Purpose : initializations for the albedo parameters |
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| 185 | !! |
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| 186 | !! ** Method : Read the namelist namalb |
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| 187 | !!---------------------------------------------------------------------- |
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[719] | 188 | NAMELIST/namalb/ cgren, albice, alphd, alphdi, alphc |
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| 189 | !!---------------------------------------------------------------------- |
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[165] | 190 | |
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[719] | 191 | ! set the initialization flag to 1 |
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| 192 | albd_init = 1 ! indicate that the initialization has been done |
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| 193 | |
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| 194 | ! Read Namelist namalb : albedo parameters |
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| 195 | REWIND( numnam ) |
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[165] | 196 | READ ( numnam, namalb ) |
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| 197 | |
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[888] | 198 | IF(lwp) THEN ! Control print |
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[165] | 199 | WRITE(numout,*) |
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[888] | 200 | WRITE(numout,*) 'albedo_init : set albedo parameters from namelist namalb' |
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[165] | 201 | WRITE(numout,*) '~~~~~~~~~~~' |
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[888] | 202 | WRITE(numout,*) ' correction for snow and ice albedo cgren = ', cgren |
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| 203 | WRITE(numout,*) ' albedo of melting ice in the arctic and antarctic albice = ', albice |
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| 204 | WRITE(numout,*) ' coefficients for linear alphd = ', alphd |
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| 205 | WRITE(numout,*) ' interpolation used to compute albedo alphdi = ', alphdi |
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| 206 | WRITE(numout,*) ' between two extremes values (Pyane, 1972) alphc = ', alphc |
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[165] | 207 | ENDIF |
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[888] | 208 | ! |
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| 209 | END SUBROUTINE albedo_init |
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[719] | 210 | |
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[152] | 211 | !!====================================================================== |
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| 212 | END MODULE albedo |
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