1 | !> \file bmelt-ismip6-param.f90 |
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2 | !! bmelt computed from the non-local formulation suggested in ismip6 |
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3 | !< |
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4 | |
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5 | !> \namespace bmelt-ismip6-param |
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6 | !! Module for sub-shelf basal melting (grounded or ice shelves) |
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7 | !! \author aquiquet |
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8 | !! \date April 2019 |
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9 | !! @note from ismip6 suggested parametrisation |
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10 | !! Should be chosen in the module_choix |
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11 | !! @note Used modules |
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12 | !! @note - use module3D_phy |
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13 | !! @note - use netcdf |
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14 | !! @note - use io_netcdf_grisli |
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15 | !< |
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16 | |
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17 | module bmelt_ismip6_param_mod |
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18 | |
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19 | use module3D_phy,only: nx,ny,dx,dy,ro,rofresh,row,cl,S,H,sealevel_2d,flot,bmelt,dirnameinp,num_param,num_rep_42 |
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20 | ! note: the geom. (nx,ny,dx,dy) come from module_geoplace |
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21 | ! note: the densities come from param_phy_mod |
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22 | use netcdf |
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23 | use io_netcdf_grisli |
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24 | |
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25 | implicit none |
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26 | |
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27 | integer, parameter :: nzoc = 30 !< number of vertical levels in the ocean |
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28 | real*8,parameter :: cpw = 3974.d0 !Specific heat of sea water (J/kg/K) |
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29 | |
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30 | real*8, dimension (nx,ny,nzoc) :: thermal_forcing !< thermal forcing , input |
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31 | real*8, dimension (nzoc) :: zoc !< depth of oceanic levels , input |
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32 | real*8, dimension (nx,ny) :: basinNumber !< IMBIE2 oc. basin identifier, input |
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33 | real*8, dimension (nx,ny) :: deltaT_basin !< deltaT , input |
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34 | real*8 :: gamma0 !< gamma0 , input |
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35 | |
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36 | real*8, dimension (nx,ny) :: mesh_area !< grid cell area |
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37 | real*8, dimension (nx,ny) :: ice_draft !< ice draft (S-H) |
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38 | |
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39 | real*8 :: cste !< a pre-computed constant |
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40 | integer :: Nbasin !< number of oceanic basin |
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41 | |
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42 | contains |
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43 | |
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44 | |
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45 | |
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46 | subroutine init_bmelt |
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47 | |
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48 | ! this routine is used to initialise the sub-shelf basal melting rate |
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49 | |
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50 | |
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51 | real*8, dimension(:), pointer :: tab1d => null() !< 2d array real pointer, needed for netcdf readings |
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52 | real*8, dimension(:,:), pointer :: tab2d => null() !< 2d array real pointer, needed for netcdf readings |
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53 | real*8, dimension(:,:,:), pointer :: tab3d => null() !< 3d array real pointer, needed for netcdf readings |
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54 | |
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55 | character(len=100) :: file_inputs !< files read |
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56 | character(len=100) :: file_TF !< files read |
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57 | character(len=100) :: file_basinNumbers !< files read |
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58 | character(len=100) :: file_coef !< files read |
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59 | |
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60 | integer i,j !juste pour les verifs |
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61 | |
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62 | namelist/bmelt_ismip6_param/file_TF,file_basinNumbers,file_coef,gamma0 |
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63 | |
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64 | rewind(num_param) ! loop back at the beginning of the param_list.dat file |
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65 | read(num_param,bmelt_ismip6_param) |
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66 | write(num_rep_42,'(A)') '! module bmelt_ismip6_param' |
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67 | write(num_rep_42,bmelt_ismip6_param) |
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68 | write(num_rep_42,'(A)') '! file_TF: 3d thermal forcing' |
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69 | write(num_rep_42,'(A)') '! file_basinNumbers: identifier for the Imbie2 basins' |
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70 | write(num_rep_42,'(A)') '! file_coef: deltaT' |
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71 | write(num_rep_42,'(A)') '! gamma0: value associated with the deltaT file' |
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72 | |
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73 | |
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74 | file_inputs=TRIM(DIRNAMEINP)//trim(file_TF) |
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75 | call Read_Ncdf_var('z',file_inputs,tab1d) |
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76 | zoc(:) = tab1d(:) |
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77 | call Read_Ncdf_var('thermal_forcing',file_inputs,tab3d) |
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78 | thermal_forcing(:,:,:) = tab3d(:,:,:) |
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79 | |
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80 | file_inputs=TRIM(DIRNAMEINP)//trim(file_basinNumbers) |
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81 | call Read_Ncdf_var('basinNumber',file_inputs,tab2d) |
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82 | basinNumber(:,:) = tab2d(:,:) |
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83 | |
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84 | file_inputs=TRIM(DIRNAMEINP)//trim(file_coef) |
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85 | call Read_Ncdf_var('deltaT_basin',file_inputs,tab2d) |
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86 | deltaT_basin(:,:) = tab2d(:,:) |
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87 | |
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88 | if ( ubound(zoc,dim=1).ne.nzoc) then |
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89 | write (*,*) "bmelt-ismip6-param: pb with the number of oceanic layers! abort..." |
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90 | STOP |
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91 | endif |
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92 | |
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93 | mesh_area(:,:) = dx*dy ! this could be corrected to account for projection deformation |
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94 | |
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95 | Nbasin=maxval(basinNumber)+1 ! number of basins |
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96 | |
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97 | cste = (row*cpw/(ro*cl))**2 ! in K^(-2) |
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98 | |
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99 | where (thermal_forcing(:,:,:).lt.0.d0) |
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100 | thermal_forcing(:,:,:) = 3.5 |
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101 | endwhere |
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102 | |
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103 | end subroutine init_bmelt |
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104 | |
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105 | |
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106 | |
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107 | subroutine bmeltshelf |
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108 | |
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109 | ! this routine is used to compute the sub-shelf basal melting rate |
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110 | |
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111 | real*8, dimension(nx,ny) :: TF_draft |
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112 | real*8,allocatable,dimension(:) :: mean_TF, IS_area |
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113 | |
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114 | integer :: i,j,k,kinf,ksup,ngr |
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115 | real*8 :: bmloc |
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116 | |
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117 | allocate( mean_TF(Nbasin), IS_area(Nbasin) ) |
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118 | |
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119 | mean_TF(:) = 0.d0 |
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120 | IS_area(:) = 0.d0 |
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121 | |
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122 | ice_draft(:,:) = S(:,:)-H(:,:)-sealevel_2d(:,:) |
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123 | |
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124 | do j=1,ny |
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125 | do i=1,nx |
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126 | |
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127 | if (flot(i,j)) then |
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128 | |
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129 | if (H(i,j).gt.200.d0) then !limit on the critical thickness of ice to define the ice shelf mask |
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130 | ! we should use Hcalv |
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131 | |
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132 | ! 1 - Linear interpolation of the thermal forcing on the ice draft depth : |
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133 | ksup=nzoc |
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134 | do k=nzoc-1,2,-1 |
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135 | if ( zoc(k) .le. ice_draft(i,j) ) ksup = k |
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136 | enddo |
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137 | kinf = ksup - 1 |
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138 | if ( ice_draft(i,j) .gt. zoc(1) ) then |
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139 | TF_draft(i,j) = thermal_forcing(i,j,1) |
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140 | elseif ( ice_draft(i,j) .lt. zoc(nzoc) ) then |
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141 | TF_draft(i,j) = thermal_forcing(i,j,nzoc) |
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142 | else |
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143 | TF_draft(i,j) = ( (zoc(ksup)-ice_draft(i,j)) * thermal_forcing(i,j,kinf) & |
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144 | & + (ice_draft(i,j)-zoc(kinf)) * thermal_forcing(i,j,ksup) ) / (zoc(ksup)-zoc(kinf)) |
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145 | endif |
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146 | |
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147 | ! 2 - Mean Thermal forcing in individual basins (NB: fortran norm while basins start at zero) : |
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148 | mean_TF( basinNumber(i,j)+1 ) = mean_TF( basinNumber(i,j)+1 ) + mesh_area(i,j) * TF_draft(i,j) |
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149 | IS_area( basinNumber(i,j)+1 ) = IS_area( basinNumber(i,j)+1 ) + mesh_area(i,j) |
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150 | |
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151 | else |
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152 | TF_draft(i,j) = thermal_forcing(i,j,1) |
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153 | endif |
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154 | |
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155 | else |
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156 | |
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157 | TF_draft(i,j) = -9999.9d0 |
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158 | |
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159 | endif |
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160 | |
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161 | enddo |
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162 | enddo |
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163 | |
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164 | where ( IS_area(:).gt.0.d0) ! for all basins that have ice shelves |
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165 | mean_TF(:) = mean_TF(:) / IS_area(:) |
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166 | elsewhere ! we have no floating points over the whole basin |
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167 | mean_TF(:) = -9999.d0 |
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168 | endwhere |
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169 | |
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170 | ! 3 - Calculation of melting rate : |
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171 | |
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172 | ! melt rate in m/yr (meters of pure water per year) : |
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173 | ! [ * rhofw_SI / rhoi_SI to get it in meters of ice per year ] |
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174 | do j=1,ny |
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175 | do i=1,nx |
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176 | if ( TF_draft(i,j) .gt. -5.d0 ) then !floating points |
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177 | if ((mean_TF(basinNumber(i,j)+1).gt.-9999.d0).and.(H(i,j).gt.200.)) then !should use Hcoup |
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178 | bmelt(i,j) = gamma0 * cste * ( TF_draft(i,j) + deltaT_basin(i,j) )* abs( mean_TF(basinNumber(i,j)+1) + deltaT_basin(i,j) ) |
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179 | !if (bmelt(i,j).lt.-0.2) then |
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180 | ! write(*,*) "Strong sub-shelf refreezing: ", bmelt(i,j), i,j,flot(i,j),ice_draft(i,j),TF_draft(i,j), mean_TF(basinNumber(i,j)+1), deltaT_basin(i,j) |
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181 | !endif |
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182 | else ! in case we have no floating points over a whole basin, we take the local expression |
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183 | bmelt(i,j) = gamma0 * cste * max( TF_draft(i,j) + deltaT_basin(i,j) , 0.d0 ) * max( TF_draft(i,j) + deltaT_basin(i,j) , 0.d0 ) |
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184 | endif |
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185 | endif |
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186 | enddo |
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187 | enddo |
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188 | |
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189 | do j=1,ny |
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190 | do i=1,nx |
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191 | if ( TF_draft(i,j) .le. -5.d0 ) then !grounded points |
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192 | ngr=0 |
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193 | bmloc=0.d0 |
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194 | if (flot(i+1,j)) then |
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195 | ngr=ngr+1 |
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196 | bmloc=bmloc+bmelt(i+1,j) |
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197 | endif |
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198 | if (flot(i-1,j)) then |
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199 | ngr=ngr+1 |
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200 | bmloc=bmloc+bmelt(i-1,j) |
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201 | endif |
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202 | if (flot(i,j+1)) then |
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203 | ngr=ngr+1 |
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204 | bmloc=bmloc+bmelt(i,j+1) |
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205 | endif |
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206 | if (flot(i,j-1)) then |
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207 | ngr=ngr+1 |
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208 | bmloc=bmloc+bmelt(i,j-1) |
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209 | endif |
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210 | bmelt(i,j)=(ngr/4.)*bmloc+(1-ngr/4.)*bmelt(i,j) |
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211 | endif |
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212 | enddo |
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213 | enddo |
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214 | |
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215 | |
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216 | end subroutine bmeltshelf |
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217 | |
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218 | |
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219 | |
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220 | end module bmelt_ismip6_param_mod |
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