1 | MODULE zdfmxl |
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2 | !!====================================================================== |
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3 | !! *** MODULE zdfmxl *** |
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4 | !! Ocean physics: mixed layer depth |
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5 | !!====================================================================== |
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6 | !! History : 1.0 ! 2003-08 (G. Madec) original code |
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7 | !! 3.2 ! 2009-07 (S. Masson, G. Madec) IOM + merge of DO-loop |
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8 | !! 3.7 ! 2012-03 (G. Madec) make public the density criteria for trdmxl |
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9 | !! - ! 2014-02 (F. Roquet) mixed layer depth calculated using N2 instead of rhop |
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10 | !!---------------------------------------------------------------------- |
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11 | !! zdf_mxl : Compute the turbocline and mixed layer depths. |
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12 | !!---------------------------------------------------------------------- |
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13 | USE oce ! ocean dynamics and tracers variables |
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14 | USE dom_oce ! ocean space and time domain variables |
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15 | USE zdf_oce ! ocean vertical physics |
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16 | USE in_out_manager ! I/O manager |
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17 | USE prtctl ! Print control |
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18 | USE phycst ! physical constants |
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19 | USE iom ! I/O library |
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20 | USE eosbn2 ! for zdf_mxl_zint |
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21 | USE lib_mpp ! MPP library |
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22 | USE wrk_nemo ! work arrays |
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23 | USE timing ! Timing |
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24 | USE trc_oce, ONLY : lk_offline ! offline flag |
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25 | |
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26 | IMPLICIT NONE |
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27 | PRIVATE |
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28 | |
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29 | PUBLIC zdf_mxl ! called by step.F90 |
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30 | PUBLIC zdf_mxl_alloc ! Used in zdf_tke_init |
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31 | |
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32 | INTEGER , PUBLIC, ALLOCATABLE, SAVE, DIMENSION(:,:) :: nmln !: number of level in the mixed layer (used by TOP) |
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33 | REAL(wp), PUBLIC, ALLOCATABLE, SAVE, DIMENSION(:,:) :: hmld !: mixing layer depth (turbocline) [m] |
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34 | REAL(wp), PUBLIC, ALLOCATABLE, SAVE, DIMENSION(:,:) :: hmlp !: mixed layer depth (rho=rho0+zdcrit) [m] |
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35 | REAL(wp), PUBLIC, ALLOCATABLE, SAVE, DIMENSION(:,:) :: hmlpt !: mixed layer depth at t-points [m] |
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36 | REAL(wp), PUBLIC, ALLOCATABLE, SAVE, DIMENSION(:,:) :: hmld_zint !: vertically-interpolated mixed layer depth [m] |
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37 | LOGICAL, PUBLIC, ALLOCATABLE, SAVE, DIMENSION(:,:) :: ll_found ! Is T_b to be found by interpolation ? |
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38 | LOGICAL, PUBLIC, ALLOCATABLE, SAVE, DIMENSION(:,:,:) :: ll_belowml ! Flag points below mixed layer when ll_found=F |
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39 | |
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40 | REAL(wp), PUBLIC :: rho_c = 0.01_wp !: density criterion for mixed layer depth |
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41 | REAL(wp) :: avt_c = 5.e-4_wp ! Kz criterion for the turbocline depth |
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42 | |
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43 | ! Namelist variables for namzdf_mldzint |
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44 | INTEGER :: nn_mld_type ! mixed layer type |
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45 | REAL(wp) :: rn_zref ! depth of initial T_ref |
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46 | REAL(wp) :: rn_dT_crit ! Critical temp diff |
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47 | REAL(wp) :: rn_iso_frac ! Fraction of rn_dT_crit used |
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48 | |
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49 | !! * Substitutions |
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50 | # include "domzgr_substitute.h90" |
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51 | !!---------------------------------------------------------------------- |
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52 | !! NEMO/OPA 4.0 , NEMO Consortium (2011) |
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53 | !! $Id$ |
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54 | !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) |
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55 | !!---------------------------------------------------------------------- |
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56 | CONTAINS |
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57 | |
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58 | INTEGER FUNCTION zdf_mxl_alloc() |
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59 | !!---------------------------------------------------------------------- |
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60 | !! *** FUNCTION zdf_mxl_alloc *** |
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61 | !!---------------------------------------------------------------------- |
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62 | zdf_mxl_alloc = 0 ! set to zero if no array to be allocated |
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63 | IF( .NOT. ALLOCATED( nmln ) ) THEN |
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64 | ALLOCATE( nmln(jpi,jpj), hmld(jpi,jpj), hmlp(jpi,jpj), hmlpt(jpi,jpj), hmld_zint(jpi,jpj), & |
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65 | & ll_found(jpi,jpj), ll_belowml(jpi,jpj,jpk), STAT= zdf_mxl_alloc ) |
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66 | ! |
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67 | IF( lk_mpp ) CALL mpp_sum ( zdf_mxl_alloc ) |
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68 | IF( zdf_mxl_alloc /= 0 ) CALL ctl_warn('zdf_mxl_alloc: failed to allocate arrays.') |
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69 | ! |
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70 | ENDIF |
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71 | END FUNCTION zdf_mxl_alloc |
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72 | |
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73 | |
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74 | SUBROUTINE zdf_mxl( kt ) |
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75 | !!---------------------------------------------------------------------- |
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76 | !! *** ROUTINE zdfmxl *** |
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77 | !! |
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78 | !! ** Purpose : Compute the turbocline depth and the mixed layer depth |
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79 | !! with density criteria. |
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80 | !! |
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81 | !! ** Method : The mixed layer depth is the shallowest W depth with |
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82 | !! the density of the corresponding T point (just bellow) bellow a |
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83 | !! given value defined locally as rho(10m) + rho_c |
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84 | !! The turbocline depth is the depth at which the vertical |
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85 | !! eddy diffusivity coefficient (resulting from the vertical physics |
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86 | !! alone, not the isopycnal part, see trazdf.F) fall below a given |
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87 | !! value defined locally (avt_c here taken equal to 5 cm/s2 by default) |
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88 | !! |
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89 | !! ** Action : nmln, hmld, hmlp, hmlpt |
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90 | !!---------------------------------------------------------------------- |
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91 | INTEGER, INTENT(in) :: kt ! ocean time-step index |
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92 | ! |
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93 | INTEGER :: ji, jj, jk ! dummy loop indices |
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94 | INTEGER :: iikn, iiki, ikt, imkt ! local integer |
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95 | REAL(wp) :: zN2_c ! local scalar |
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96 | INTEGER, POINTER, DIMENSION(:,:) :: imld ! 2D workspace |
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97 | !!---------------------------------------------------------------------- |
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98 | ! |
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99 | IF( nn_timing == 1 ) CALL timing_start('zdf_mxl') |
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100 | ! |
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101 | CALL wrk_alloc( jpi,jpj, imld ) |
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102 | |
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103 | IF( kt <= nit000 ) THEN |
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104 | IF(lwp) WRITE(numout,*) |
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105 | IF(lwp) WRITE(numout,*) 'zdf_mxl : mixed layer depth' |
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106 | IF(lwp) WRITE(numout,*) '~~~~~~~ ' |
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107 | ! ! allocate zdfmxl arrays |
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108 | IF( zdf_mxl_alloc() /= 0 ) CALL ctl_stop( 'STOP', 'zdf_mxl : unable to allocate arrays' ) |
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109 | ENDIF |
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110 | |
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111 | ! w-level of the mixing and mixed layers |
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112 | nmln(:,:) = nlb10 ! Initialization to the number of w ocean point |
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113 | hmlp(:,:) = 0._wp ! here hmlp used as a dummy variable, integrating vertically N^2 |
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114 | zN2_c = grav * rho_c * r1_rau0 ! convert density criteria into N^2 criteria |
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115 | DO jk = nlb10, jpkm1 |
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116 | DO jj = 1, jpj ! Mixed layer level: w-level |
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117 | DO ji = 1, jpi |
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118 | ikt = mbkt(ji,jj) |
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119 | hmlp(ji,jj) = hmlp(ji,jj) + MAX( rn2b(ji,jj,jk) , 0._wp ) * fse3w(ji,jj,jk) |
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120 | IF( hmlp(ji,jj) < zN2_c ) nmln(ji,jj) = MIN( jk , ikt ) + 1 ! Mixed layer level |
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121 | END DO |
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122 | END DO |
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123 | END DO |
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124 | ! |
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125 | ! w-level of the turbocline |
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126 | imld(:,:) = mbkt(:,:) + 1 ! Initialization to the number of w ocean point |
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127 | DO jk = jpkm1, nlb10, -1 ! from the bottom to nlb10 |
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128 | DO jj = 1, jpj |
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129 | DO ji = 1, jpi |
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130 | imkt = mikt(ji,jj) |
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131 | IF( avt (ji,jj,jk) < avt_c ) imld(ji,jj) = MAX( imkt, jk ) ! Turbocline |
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132 | END DO |
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133 | END DO |
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134 | END DO |
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135 | ! depth of the mixing and mixed layers |
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136 | DO jj = 1, jpj |
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137 | DO ji = 1, jpi |
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138 | iiki = imld(ji,jj) |
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139 | iikn = nmln(ji,jj) |
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140 | imkt = mikt(ji,jj) |
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141 | hmld (ji,jj) = ( fsdepw(ji,jj,iiki ) - fsdepw(ji,jj,imkt ) ) * ssmask(ji,jj) ! Turbocline depth |
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142 | hmlp (ji,jj) = ( fsdepw(ji,jj,iikn ) - fsdepw(ji,jj,imkt ) ) * ssmask(ji,jj) ! Mixed layer depth |
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143 | hmlpt(ji,jj) = ( fsdept(ji,jj,iikn-1) - fsdepw(ji,jj,imkt ) ) * ssmask(ji,jj) ! depth of the last T-point inside the mixed layer |
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144 | END DO |
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145 | END DO |
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146 | IF( .NOT.lk_offline ) THEN ! no need to output in offline mode |
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147 | IF( kt >= nit000 ) THEN ! workaround for calls before SOMETHING reads the XIOS namelist |
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148 | CALL iom_put( "mldr10_1", hmlp ) ! mixed layer depth |
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149 | CALL iom_put( "mldkz5" , hmld ) ! turbocline depth |
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150 | ENDIF |
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151 | ENDIF |
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152 | |
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153 | ! Vertically-interpolated mixed-layer depth diagnostic |
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154 | IF( iom_use( "mldzint" ) ) THEN |
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155 | CALL zdf_mxl_zint( kt ) |
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156 | CALL iom_put( "mldzint" , hmld_zint ) |
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157 | ENDIF |
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158 | |
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159 | IF(ln_ctl) CALL prt_ctl( tab2d_1=REAL(nmln,wp), clinfo1=' nmln : ', tab2d_2=hmlp, clinfo2=' hmlp : ', ovlap=1 ) |
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160 | ! |
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161 | CALL wrk_dealloc( jpi,jpj, imld ) |
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162 | ! |
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163 | IF( nn_timing == 1 ) CALL timing_stop('zdf_mxl') |
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164 | ! |
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165 | END SUBROUTINE zdf_mxl |
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166 | |
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167 | SUBROUTINE zdf_mxl_zint( kt ) |
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168 | !!---------------------------------------------------------------------------------- |
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169 | !! *** ROUTINE zdf_mxl_zint *** |
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170 | ! |
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171 | ! Calculate vertically-interpolated mixed layer depth diagnostic. |
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172 | ! |
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173 | ! This routine can calculate the mixed layer depth diagnostic suggested by |
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174 | ! Kara et al, 2000, JGR, 105, 16803, but is more general and can calculate |
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175 | ! vertically-interpolated mixed-layer depth diagnostics with other parameter |
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176 | ! settings set in the namzdf_mldzint namelist. |
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177 | ! |
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178 | ! If mld_type=1 the mixed layer depth is calculated as the depth at which the |
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179 | ! density has increased by an amount equivalent to a temperature difference of |
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180 | ! 0.8C at the surface. |
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181 | ! |
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182 | ! For other values of mld_type the mixed layer is calculated as the depth at |
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183 | ! which the temperature differs by 0.8C from the surface temperature. |
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184 | ! |
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185 | ! David Acreman, Daley Calvert |
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186 | ! |
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187 | !!----------------------------------------------------------------------------------- |
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188 | |
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189 | INTEGER, INTENT(in) :: kt ! ocean time-step index |
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190 | ! |
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191 | ! Local variables |
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192 | INTEGER, POINTER, DIMENSION(:,:) :: ikmt ! number of active tracer levels |
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193 | INTEGER, POINTER, DIMENSION(:,:) :: ik_ref ! index of reference level |
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194 | INTEGER, POINTER, DIMENSION(:,:) :: ik_iso ! index of last uniform temp level |
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195 | REAL, POINTER, DIMENSION(:,:,:) :: zT ! Temperature or density |
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196 | REAL, POINTER, DIMENSION(:,:) :: ppzdep ! depth for use in calculating d(rho) |
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197 | REAL, POINTER, DIMENSION(:,:) :: zT_ref ! reference temperature |
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198 | REAL :: zT_b ! base temperature |
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199 | REAL, POINTER, DIMENSION(:,:,:) :: zdTdz ! gradient of zT |
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200 | REAL, POINTER, DIMENSION(:,:,:) :: zmoddT ! Absolute temperature difference |
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201 | REAL :: zdz ! depth difference |
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202 | REAL :: zdT ! temperature difference |
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203 | REAL, POINTER, DIMENSION(:,:) :: zdelta_T ! difference critereon |
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204 | REAL, POINTER, DIMENSION(:,:) :: zRHO1, zRHO2 ! Densities |
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205 | INTEGER :: ji, jj, jk ! loop counter |
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206 | INTEGER :: ios |
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207 | |
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208 | NAMELIST/namzdf_mldzint/ nn_mld_type, rn_zref, rn_dT_crit, rn_iso_frac |
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209 | |
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210 | !!------------------------------------------------------------------------------------- |
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211 | ! |
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212 | CALL wrk_alloc( jpi, jpj, ikmt, ik_ref, ik_iso) |
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213 | CALL wrk_alloc( jpi, jpj, ppzdep, zT_ref, zdelta_T, zRHO1, zRHO2 ) |
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214 | CALL wrk_alloc( jpi, jpj, jpk, zT, zdTdz, zmoddT ) |
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215 | |
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216 | IF( kt == nit000 ) THEN |
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217 | REWIND( numnam_ref ) ! Namelist namzdf_mldzint in reference namelist |
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218 | READ ( numnam_ref, namzdf_mldzint, IOSTAT = ios, ERR = 901) |
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219 | 901 IF( ios /= 0 ) CALL ctl_nam ( ios , 'namzdf_mldzint in reference namelist', lwp ) |
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220 | |
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221 | REWIND( numnam_cfg ) ! Namelist namzdf_mldzint in configuration namelist |
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222 | READ ( numnam_cfg, namzdf_mldzint, IOSTAT = ios, ERR = 902 ) |
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223 | 902 IF( ios /= 0 ) CALL ctl_nam ( ios , 'namzdf_mldzint in configuration namelist', lwp ) |
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224 | IF(lwm) WRITE ( numond, namzdf_mldzint ) |
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225 | |
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226 | WRITE(numout,*) '===== Vertically-interpolated mixed layer =====' |
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227 | WRITE(numout,*) 'nn_mld_type = ',nn_mld_type |
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228 | WRITE(numout,*) 'rn_zref = ',rn_zref |
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229 | WRITE(numout,*) 'rn_dT_crit = ',rn_dT_crit |
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230 | WRITE(numout,*) 'rn_iso_frac = ',rn_iso_frac |
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231 | WRITE(numout,*) '===============================================' |
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232 | ENDIF |
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233 | |
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234 | ! Set the mixed layer depth criterion at each grid point |
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235 | IF (nn_mld_type == 1) THEN |
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236 | ppzdep(:,:)=0.0 |
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237 | call eos ( tsn(:,:,1,:), ppzdep(:,:), zRHO1(:,:) ) |
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238 | ! Use zT temporarily as a copy of tsn with rn_dT_crit added to SST |
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239 | ! [assumes number of tracers less than number of vertical levels] |
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240 | zT(:,:,1:jpts)=tsn(:,:,1,1:jpts) |
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241 | zT(:,:,jp_tem)=zT(:,:,1)+rn_dT_crit |
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242 | CALL eos( zT(:,:,1:jpts), ppzdep(:,:), zRHO2(:,:) ) |
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243 | zdelta_T(:,:) = abs( zRHO1(:,:) - zRHO2(:,:) ) * rau0 |
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244 | ! RHO from eos (2d version) doesn't calculate north or east halo: |
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245 | CALL lbc_lnk( zdelta_T, 'T', 1. ) |
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246 | zT(:,:,:) = rhop(:,:,:) |
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247 | ELSE |
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248 | zdelta_T(:,:) = rn_dT_crit |
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249 | zT(:,:,:) = tsn(:,:,:,jp_tem) |
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250 | END IF |
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251 | |
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252 | ! Calculate the gradient of zT and absolute difference for use later |
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253 | DO jk = 1 ,jpk-2 |
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254 | zdTdz(:,:,jk) = ( zT(:,:,jk+1) - zT(:,:,jk) ) / fse3w(:,:,jk+1) |
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255 | zmoddT(:,:,jk) = abs( zT(:,:,jk+1) - zT(:,:,jk) ) |
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256 | END DO |
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257 | |
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258 | ! Find density/temperature at the reference level (Kara et al use 10m). |
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259 | ! ik_ref is the index of the box centre immediately above or at the reference level |
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260 | ! Find rn_zref in the array of model level depths and find the ref |
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261 | ! density/temperature by linear interpolation. |
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262 | DO jk = jpkm1, 2, -1 |
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263 | WHERE ( fsdept(:,:,jk) > rn_zref ) |
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264 | ik_ref(:,:) = jk - 1 |
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265 | zT_ref(:,:) = zT(:,:,jk-1) + zdTdz(:,:,jk-1) * ( rn_zref - fsdept(:,:,jk-1) ) |
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266 | END WHERE |
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267 | END DO |
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268 | |
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269 | ! If the first grid box centre is below the reference level then use the |
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270 | ! top model level to get zT_ref |
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271 | WHERE ( fsdept(:,:,1) > rn_zref ) |
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272 | zT_ref = zT(:,:,1) |
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273 | ik_ref = 1 |
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274 | END WHERE |
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275 | |
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276 | ! The number of active tracer levels is 1 less than the number of active w levels |
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277 | ikmt(:,:) = mbathy(:,:) - 1 |
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278 | |
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279 | ! Search for a uniform density/temperature region where adjacent levels |
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280 | ! differ by less than rn_iso_frac * deltaT. |
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281 | ! ik_iso is the index of the last level in the uniform layer |
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282 | ! ll_found indicates whether the mixed layer depth can be found by interpolation |
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283 | ik_iso(:,:) = ik_ref(:,:) |
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284 | ll_found(:,:) = .false. |
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285 | DO jj = 1, nlcj |
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286 | DO ji = 1, nlci |
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287 | !CDIR NOVECTOR |
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288 | DO jk = ik_ref(ji,jj), ikmt(ji,jj)-1 |
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289 | IF ( zmoddT(ji,jj,jk) > ( rn_iso_frac * zdelta_T(ji,jj) ) ) THEN |
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290 | ik_iso(ji,jj) = jk |
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291 | ll_found(ji,jj) = ( zmoddT(ji,jj,jk) > zdelta_T(ji,jj) ) |
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292 | EXIT |
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293 | END IF |
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294 | END DO |
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295 | END DO |
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296 | END DO |
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297 | |
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298 | ! Use linear interpolation to find depth of mixed layer base where possible |
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299 | hmld_zint(:,:) = rn_zref |
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300 | DO jj = 1, jpj |
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301 | DO ji = 1, jpi |
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302 | IF (ll_found(ji,jj) .and. tmask(ji,jj,1) == 1.0) THEN |
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303 | zdz = abs( zdelta_T(ji,jj) / zdTdz(ji,jj,ik_iso(ji,jj)) ) |
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304 | hmld_zint(ji,jj) = fsdept(ji,jj,ik_iso(ji,jj)) + zdz |
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305 | END IF |
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306 | END DO |
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307 | END DO |
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308 | |
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309 | ! If ll_found = .false. then calculate MLD using difference of zdelta_T |
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310 | ! from the reference density/temperature |
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311 | |
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312 | ! Prevent this section from working on land points |
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313 | WHERE ( tmask(:,:,1) /= 1.0 ) |
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314 | ll_found = .true. |
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315 | END WHERE |
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316 | |
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317 | DO jk=1, jpk |
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318 | ll_belowml(:,:,jk) = abs( zT(:,:,jk) - zT_ref(:,:) ) >= zdelta_T(:,:) |
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319 | END DO |
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320 | |
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321 | ! Set default value where interpolation cannot be used (ll_found=false) |
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322 | DO jj = 1, jpj |
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323 | DO ji = 1, jpi |
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324 | IF ( .not. ll_found(ji,jj) ) hmld_zint(ji,jj) = fsdept(ji,jj,ikmt(ji,jj)) |
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325 | END DO |
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326 | END DO |
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327 | |
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328 | DO jj = 1, jpj |
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329 | DO ji = 1, jpi |
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330 | !CDIR NOVECTOR |
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331 | DO jk = ik_ref(ji,jj)+1, ikmt(ji,jj) |
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332 | IF ( ll_found(ji,jj) ) EXIT |
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333 | IF ( ll_belowml(ji,jj,jk) ) THEN |
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334 | zT_b = zT_ref(ji,jj) + zdelta_T(ji,jj) * SIGN(1.0, zdTdz(ji,jj,jk-1) ) |
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335 | zdT = zT_b - zT(ji,jj,jk-1) |
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336 | zdz = zdT / zdTdz(ji,jj,jk-1) |
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337 | hmld_zint(ji,jj) = fsdept(ji,jj,jk-1) + zdz |
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338 | EXIT |
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339 | END IF |
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340 | END DO |
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341 | END DO |
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342 | END DO |
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343 | |
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344 | hmld_zint(:,:) = hmld_zint(:,:)*tmask(:,:,1) |
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345 | ! |
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346 | CALL wrk_dealloc( jpi, jpj, ikmt, ik_ref, ik_iso) |
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347 | CALL wrk_dealloc( jpi, jpj, ppzdep, zT_ref, zdelta_T, zRHO1, zRHO2 ) |
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348 | CALL wrk_dealloc( jpi,jpj, jpk, zT, zdTdz, zmoddT ) |
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349 | ! |
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350 | END SUBROUTINE zdf_mxl_zint |
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351 | |
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352 | !!====================================================================== |
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353 | END MODULE zdfmxl |
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