1 | MODULE sbcdcy |
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2 | !!====================================================================== |
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3 | !! *** MODULE sbcdcy *** |
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4 | !! Ocean forcing: compute the diurnal cycle |
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5 | !!====================================================================== |
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6 | !! History : 8.2 ! 2005-02 (D. Bernie) Original code |
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7 | !! 9.0 ! 2006-02 (S. Masson, G. Madec) adaptation to OPA9 |
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8 | !! 3.1 ! 2009-07 (J.M. Molines) adaptation to nemo3.1 |
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9 | !!---------------------------------------------------------------------- |
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10 | |
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11 | !!---------------------------------------------------------------------- |
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12 | !! sbc_dcy : compute solar flux at kt from daily mean, taking |
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13 | !! diurnal cycle into account |
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14 | !!---------------------------------------------------------------------- |
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15 | USE oce ! ocean dynamics and tracers |
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16 | USE phycst ! ocean physics |
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17 | USE dom_oce ! ocean space and time domain |
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18 | USE in_out_manager ! I/O manager |
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19 | |
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20 | IMPLICIT NONE |
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21 | PRIVATE |
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22 | INTEGER :: idayqsr ! day when parameters were computed |
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23 | REAL(wp), DIMENSION(jpi,jpj) :: zaaa, zbbb, zccc, zab, ztmd, zdawn, zdusk, zscal ! parameters to compute the diurnal cycle |
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24 | REAL(wp), DIMENSION(jpi,jpj) :: qsr_daily ! to hold daily mean QSR |
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25 | |
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26 | PUBLIC sbc_dcy ! routine called by sbc |
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27 | |
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28 | !!---------------------------------------------------------------------- |
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29 | !! NEMO/OPA 3.3 , LOCEAN-IPSL (2010) |
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30 | !! $Id$ |
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31 | !! Software governed by the CeCILL licence (modipsl/doc/NEMO_CeCILL.txt) |
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32 | !!---------------------------------------------------------------------- |
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33 | |
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34 | CONTAINS |
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35 | |
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36 | SUBROUTINE sbc_dcy( kt, pqsr ) |
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37 | !!---------------------------------------------------------------------- |
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38 | !! *** ROUTINE sbc_dcy *** |
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39 | !! |
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40 | !! ** Purpose : introduce a diurnal cycle of qsr from daily values |
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41 | !! |
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42 | !! ** Method : see Appendix A of |
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43 | !! Bernie, DJ, Guilyardi, E, Madec, G, Slingo, JM and Woolnough, SJ |
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44 | !! Impact of resolving the diurnal cycle in an ocean--atmosphere GCM. Part 1: a diurnally forced OGCM |
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45 | !! Climate Dynamics 29:6, 575-590 (2007) |
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46 | !! |
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47 | !! ** Action : redistribute daily QSR on each time step following the diurnal cycle |
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48 | !!---------------------------------------------------------------------- |
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49 | INTEGER, INTENT( in ) :: kt ! ocean time-step index |
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50 | REAL(wp), DIMENSION(jpi,jpj), INTENT( inout ) :: pqsr ! QSR flux with diurnal cycle |
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51 | !! |
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52 | INTEGER :: ji, jj ! dummy loop indices |
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53 | REAL(wp) :: fintegral, pt1, pt2, paaa, pbbb, pccc ! |
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54 | REAL(wp) :: ztwopi, zinvtwopi, zconvrad |
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55 | REAL(wp) :: zlo, zup, zlousd, zupusd |
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56 | REAL(wp) :: zdsws, zdecrad, ztx |
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57 | REAL(wp) :: ztmp, ztmp1, ztmp2, ztest |
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58 | !!--------------------------------------------------------------------- |
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59 | |
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60 | !---------------------------------------------------------------------- |
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61 | ! statement functions |
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62 | |
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63 | fintegral(pt1, pt2, paaa, pbbb, pccc) = & |
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64 | & paaa * pt2 + zinvtwopi * pbbb * SIN(pccc + ztwopi * pt2) & |
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65 | & - paaa * pt1 - zinvtwopi * pbbb * SIN(pccc + ztwopi * pt1) |
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66 | !---------------------------------------------------------------------- |
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67 | |
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68 | ! Initialization |
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69 | ! -------------- |
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70 | ztwopi = 2. * rpi |
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71 | zinvtwopi = 1. / ztwopi |
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72 | zconvrad = ztwopi / 360. |
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73 | |
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74 | ! When are we during the day (from 0 to 1) |
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75 | zlo = MOD( rdt / rday * REAL( kt-nit000, wp ), 1.) |
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76 | zup = zlo + rdt / rday |
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77 | |
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78 | ! |
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79 | IF (kt == nit000) THEN |
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80 | ! |
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81 | IF(lwp) THEN |
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82 | WRITE(numout,*) |
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83 | WRITE(numout,*) 'sbc_dcy : introduce diurnal cycle from daily mean qsr' |
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84 | WRITE(numout,*) '~~~~~~~' |
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85 | WRITE(numout,*) |
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86 | ENDIF |
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87 | idayqsr = 0 |
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88 | ! Compute C needed to compute the time integral of the diurnal cycle |
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89 | zccc(:,:) = zconvrad * glamt(:,:) - rpi |
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90 | ! time of midday |
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91 | ztmd(:,:) = 0.5 - glamt(:,:) / 360. |
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92 | ztmd(:,:) = MOD((ztmd(:,:) + 1.), 1.) |
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93 | ENDIF |
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94 | |
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95 | ! If this is a new day, we have to update the dawn, dusk and scaling function |
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96 | !---------------------- |
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97 | |
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98 | ! 2.1 dawn and dusk |
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99 | |
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100 | ! nday is the number of days since the beginning of the current month |
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101 | IF( idayqsr /= nday ) THEN |
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102 | ! save the day of the year and the daily mean of qsr |
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103 | idayqsr = nday |
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104 | ! number of days since the previous winter solstice (supposed to be always 21 December) |
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105 | zdsws = 11 + nday_year |
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106 | ! declination of the earths orbit |
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107 | zdecrad = (-23.5 * zconvrad) * COS( zdsws * ztwopi / REAL(nyear_len(1),wp) ) |
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108 | ! save the daily QSR for nest hours of the day |
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109 | qsr_daily(:,:) = pqsr(:,:) |
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110 | ! Compute A and B needed to compute the time integral of the diurnal cycle |
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111 | |
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112 | DO jj = 1, jpj |
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113 | DO ji = 1, jpi |
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114 | ztmp = zconvrad * gphit(ji,jj) |
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115 | zaaa(ji,jj) = SIN(ztmp) * SIN(zdecrad) |
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116 | zbbb(ji,jj) = COS(ztmp) * COS(zdecrad) |
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117 | END DO |
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118 | END DO |
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119 | |
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120 | ! Compute the time of dawn and dusk |
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121 | |
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122 | ! zab to test if the day time is equal to 0, less than 24h of full day |
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123 | zab(:,:) = -zaaa(:,:) / zbbb(:,:) |
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124 | DO jj = 1, jpj |
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125 | DO ji = 1, jpi |
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126 | IF ( ABS(zab(ji,jj)) < 1 ) THEN |
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127 | ! day duration is less than 24h |
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128 | ! When is it night? |
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129 | ztx = zinvtwopi * (ACOS(zab(ji,jj)) - zccc(ji,jj)) |
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130 | ztest = -zbbb(ji,jj) * SIN( zccc(ji,jj) + ztwopi * ztx ) |
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131 | ! is it dawn or dusk? |
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132 | IF ( ztest > 0 ) THEN |
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133 | zdawn(ji,jj) = ztx |
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134 | zdusk(ji,jj) = ztmd(ji,jj) + ( ztmd(ji,jj) - zdawn(ji,jj) ) |
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135 | ELSE |
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136 | zdusk(ji,jj) = ztx |
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137 | zdawn(ji,jj) = ztmd(ji,jj) - ( zdusk(ji,jj) - ztmd(ji,jj) ) |
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138 | ENDIF |
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139 | ELSE |
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140 | zdawn(ji,jj) = ztmd(ji,jj) + 0.5 |
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141 | zdusk(ji,jj) = zdawn(ji,jj) |
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142 | ENDIF |
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143 | END DO |
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144 | END DO |
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145 | zdawn(:,:) = MOD((zdawn(:,:) + 1.), 1.) |
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146 | zdusk(:,:) = MOD((zdusk(:,:) + 1.), 1.) |
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147 | |
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148 | |
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149 | ! 2.2 Compute the scalling function: |
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150 | ! S* = the inverse of the time integral of the diurnal cycle from dawm to dusk |
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151 | |
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152 | DO jj = 1, jpj |
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153 | DO ji = 1, jpi |
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154 | IF ( ABS(zab(ji,jj)) < 1 ) THEN |
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155 | ! day duration is less than 24h |
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156 | IF ( zdawn(ji,jj) < zdusk(ji,jj) ) THEN |
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157 | ! day time in one part |
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158 | zscal(ji,jj) = fintegral(zdawn(ji,jj), zdusk(ji,jj), zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) |
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159 | zscal(ji,jj) = 1. / zscal(ji,jj) |
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160 | ELSE |
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161 | ! day time in two parts |
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162 | zscal(ji,jj) = fintegral(0., zdusk(ji,jj), zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) & |
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163 | & + fintegral(zdawn(ji,jj), 1., zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) |
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164 | zscal(ji,jj) = 1. / zscal(ji,jj) |
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165 | ENDIF |
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166 | ELSE |
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167 | IF ( zaaa(ji,jj) > zbbb(ji,jj) ) THEN |
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168 | ! 24h day |
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169 | zscal(ji,jj) = fintegral(0., 1., zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) |
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170 | zscal(ji,jj) = 1. / zscal(ji,jj) |
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171 | ELSE |
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172 | ! No day |
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173 | zscal(ji,jj) = 0. |
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174 | ENDIF |
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175 | ENDIF |
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176 | END DO |
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177 | END DO |
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178 | ! |
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179 | ztmp = rday / rdt |
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180 | zscal(:,:) = zscal(:,:) * ztmp |
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181 | |
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182 | ENDIF |
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183 | |
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184 | ! 3. compute qsr with the diurnal cycle |
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185 | ! ----------------------- |
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186 | |
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187 | DO jj = 1, jpj |
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188 | DO ji = 1, jpi |
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189 | IF ( ABS(zab(ji,jj)) < 1 ) THEN |
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190 | ! day duration is less than 24h |
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191 | IF ( zdawn(ji,jj) < zdusk(ji,jj) ) THEN |
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192 | ! day time in one part |
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193 | zlousd = MAX(zlo, zdawn(ji,jj)) |
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194 | zlousd = MIN(zlousd, zup) |
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195 | zupusd = MIN(zup, zdusk(ji,jj)) |
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196 | zupusd = MAX(zupusd, zlo) |
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197 | ztmp = fintegral(zlousd, zupusd, zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) |
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198 | pqsr(ji,jj) = qsr_daily(ji,jj) * ztmp * zscal(ji,jj) |
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199 | ELSE |
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200 | ! day time in two parts |
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201 | zlousd = MIN(zlo, zdusk(ji,jj)) |
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202 | zupusd = MIN(zup, zdusk(ji,jj)) |
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203 | ztmp1 = fintegral(zlousd, zupusd, zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) |
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204 | zlousd = MAX(zlo, zdawn(ji,jj)) |
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205 | zupusd = MAX(zup, zdawn(ji,jj)) |
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206 | ztmp2 = fintegral(zlousd, zupusd, zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) |
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207 | ztmp = ztmp1 + ztmp2 |
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208 | pqsr(ji,jj) = qsr_daily(ji,jj) * ztmp * zscal(ji,jj) |
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209 | ENDIF |
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210 | ELSE |
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211 | IF ( zaaa(ji,jj) > zbbb(ji,jj) ) THEN |
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212 | ! 24h day |
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213 | ztmp = fintegral(zlo, zup, zaaa(ji,jj), zbbb(ji,jj), zccc(ji,jj)) |
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214 | pqsr(ji,jj) = qsr_daily(ji,jj) * ztmp * zscal(ji,jj) |
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215 | ELSE |
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216 | ! No day |
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217 | pqsr(ji,jj) = 0. |
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218 | ENDIF |
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219 | ENDIF |
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220 | END DO |
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221 | END DO |
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222 | |
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223 | END SUBROUTINE sbc_dcy |
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224 | |
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225 | !!====================================================================== |
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226 | END MODULE sbcdcy |
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