1 | !! This module define solar |
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2 | !! |
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3 | !! @call sechiba_main |
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4 | !! @Version : $Revision$, $Date$ |
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5 | !! |
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6 | !< $HeadURL$ |
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7 | !< $Date$ |
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8 | !< $Author$ |
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9 | !< $Revision$ |
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10 | !! |
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11 | !! @author Marie-Alice Foujols, Jan Polcher and Martial Mancip |
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12 | !! |
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13 | !! |
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14 | MODULE solar |
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15 | |
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16 | USE defprec |
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17 | USE constantes |
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18 | USE parallel |
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19 | |
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20 | IMPLICIT NONE |
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21 | |
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22 | |
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23 | |
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24 | CONTAINS |
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25 | ! |
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26 | !f90doc CONTAINS |
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27 | ! |
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28 | ! |
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29 | ! |
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30 | !- |
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31 | !===================================================================== |
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32 | SUBROUTINE solarang (julian, julian0, iim, jjm, lon, lat, csang) |
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33 | !--------------------------------------------------------------------- |
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34 | !- This subroutine computes the solar angle according to the method |
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35 | !- used by GSWP and developed by J.C. Morill. |
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36 | !- See for further details : |
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37 | !- http://www.atmo.arizona.edu/~morrill/swrad.html |
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38 | !--------------------------------------------------------------------- |
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39 | ! |
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40 | USE calendar |
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41 | ! |
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42 | IMPLICIT NONE |
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43 | !- |
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44 | INTEGER,INTENT(in) :: iim, jjm |
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45 | REAL,INTENT(in) :: julian |
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46 | REAL,INTENT(in) :: julian0 |
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47 | REAL,DIMENSION(iim,jjm), INTENT(in) :: lon, lat |
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48 | REAL,DIMENSION(iim,jjm), INTENT(out) :: csang |
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49 | !- |
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50 | REAL :: pi, gamma, dec, decd |
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51 | REAL :: et, gmt, le, ls, lcorr, latime, omega, omegad |
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52 | REAL :: llatd, llat |
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53 | INTEGER :: igmt, ilon, ilat |
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54 | INTEGER,SAVE,ALLOCATABLE :: zone(:), lhour(:) |
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55 | ! |
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56 | LOGICAL :: check = .FALSE. |
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57 | !--------------------------------------------------------------------- |
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58 | ! |
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59 | pi = 4.*ATAN(1.) |
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60 | IF (check) WRITE(numout,*) 'We get the right calendar information' |
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61 | !- |
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62 | !- 1) Day angle gamma |
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63 | !- |
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64 | ! gamma = 2.*pi*MOD(julian,one_year)/one_year |
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65 | gamma = 2.*pi*(julian-julian0)/one_year |
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66 | !- |
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67 | !- 2) Solar declination (assumed constant for a 24 hour period) page 7 |
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68 | !- in radians |
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69 | !- |
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70 | IF (check) WRITE(numout,*) 'Solar declination' |
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71 | ! |
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72 | dec = ( 0.006918-0.399912*COS(gamma)+0.070257*SIN(gamma) & |
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73 | & -0.006758*COS(2*gamma)+0.000907*SIN(2*gamma) & |
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74 | & -0.002697*COS(3*gamma)+0.00148*SIN(3*gamma)) |
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75 | decd = dec*(180/pi) |
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76 | !- |
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77 | !- maximum error 0.0006 rad (<3'), leads to error |
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78 | !- of less than 1/2 degree in zenith angle |
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79 | !- |
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80 | IF (check) WRITE(numout,*) 'Equation of time' |
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81 | !- 3) Equation of time page 11 |
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82 | !- |
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83 | et = ( 0.000075+0.001868*COS(gamma)-0.032077*SIN(gamma)& |
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84 | & -0.014615*COS(2*gamma)-0.04089*SIN(2*gamma))*229.18 |
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85 | !- |
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86 | !- Get the time zones for the current time |
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87 | !- |
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88 | gmt = 24.*(julian-INT(julian)) |
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89 | IF (.NOT.ALLOCATED(zone)) ALLOCATE(zone(iim)) |
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90 | IF (.NOT.ALLOCATED(lhour)) ALLOCATE(lhour(iim)) |
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91 | !- |
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92 | igmt = NINT(gmt) |
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93 | IF (check) WRITE(numout,*) 'Get time zone' |
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94 | CALL time_zone(igmt, iim, jjm, lon, zone, lhour) |
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95 | !- |
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96 | !- Start a loop through the grid |
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97 | !- |
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98 | IF (check) WRITE(numout,*) 'Start a loop through the grid' |
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99 | DO ilon=1,iim |
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100 | !--- |
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101 | !--- 4) Local apparent time page 13 |
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102 | !--- |
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103 | !--- ls standard longitude (nearest 15 degree meridian) |
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104 | !--- le local longtitude |
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105 | !--- lhour local standard time |
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106 | !--- latime local apparent time |
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107 | !--- lcorr longitudunal correction (minutes) |
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108 | !--- |
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109 | le = lon(ilon,1) |
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110 | ls = ((zone(ilon)-1)*15)-180. |
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111 | lcorr = 4.*(ls-le)*(-1) |
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112 | latime = lhour(ilon)+lcorr/60.+et/60. |
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113 | IF (latime < 0.) latime = latime+24 |
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114 | IF (latime > 24.) latime = latime-24 |
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115 | !--- |
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116 | !--- 5) Hour angle omega page 15 |
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117 | !--- |
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118 | !--- hour angle is zero at noon, positive in the morning |
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119 | !--- It ranges from 180 to -180 |
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120 | !--- |
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121 | !--- omegad is omega in degrees, omega is in radians |
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122 | !--- |
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123 | omegad = (latime-12.)*(-15.) |
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124 | omega = omegad*pi/180. |
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125 | !--- |
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126 | DO ilat=1,jjm |
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127 | !----- |
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128 | !----- 6) Zenith angle page 15 |
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129 | !----- |
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130 | !----- csang cosine of zenith angle (radians) |
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131 | !----- llatd = local latitude in degrees |
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132 | !----- llat = local latitude in radians |
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133 | !----- |
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134 | llatd = lat(1,ilat) |
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135 | llat = llatd*pi/180. |
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136 | csang(ilon,ilat) = & |
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137 | & MAX(zero,SIN(dec)*SIN(llat)+COS(dec)*COS(llat)*COS(omega)) |
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138 | ENDDO |
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139 | ENDDO |
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140 | !---------------------- |
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141 | END SUBROUTINE solarang |
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142 | !- |
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143 | !===================================================================== |
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144 | SUBROUTINE time_zone (gmt, iim, jjm, lon, zone, lhour) |
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145 | !--------------------------------------------------------------------- |
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146 | ! |
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147 | IMPLICIT NONE |
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148 | ! |
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149 | INTEGER :: gmt, iim, jjm, zone(iim), lhour(iim) |
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150 | REAL :: lon(iim,jjm) |
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151 | !- |
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152 | INTEGER :: deg |
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153 | !!?? REAL :: deg |
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154 | INTEGER :: i, ilon, change |
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155 | !--------------------------------------------------------------------- |
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156 | DO ilon=1,iim |
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157 | !--- |
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158 | !--- Convert longitude index to longtitude in degrees |
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159 | !--- |
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160 | deg = lon(ilon,1) |
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161 | !--- |
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162 | !--- Determine into which time zone (15 degree interval) the |
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163 | !--- longitude falls. |
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164 | !--- |
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165 | DO i=1,25 |
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166 | IF (deg < (-187.5+(15*i))) THEN |
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167 | zone(ilon) = i |
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168 | IF (zone(ilon) == 25) zone(ilon) = 1 |
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169 | EXIT |
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170 | ENDIF |
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171 | ENDDO |
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172 | !--- |
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173 | !--- Calculate change (in number of hours) from GMT time to |
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174 | !--- local hour. Change will be negative for zones < 13 and |
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175 | !--- positive for zones > 13. |
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176 | !--- |
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177 | !--- There is also a correction for lhour < 0 and lhour > 23 |
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178 | !--- to lhour between 0 and 23. |
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179 | !--- |
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180 | IF (zone(ilon) < 13) THEN |
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181 | change = zone(ilon)-13 |
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182 | lhour(ilon) = gmt+change |
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183 | ENDIF |
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184 | !--- |
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185 | IF (zone(ilon) == 13) THEN |
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186 | lhour(ilon) = gmt |
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187 | ENDIF |
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188 | !--- |
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189 | IF (zone(ilon) > 13) THEN |
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190 | change = zone(ilon)-13 |
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191 | lhour(ilon) = gmt+change |
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192 | ENDIF |
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193 | IF (lhour(ilon) < 0) lhour(ilon) = lhour(ilon)+24 |
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194 | IF (lhour(ilon) > 23) lhour(ilon) = lhour(ilon)-24 |
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195 | !--- |
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196 | ENDDO |
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197 | !----------------------- |
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198 | END SUBROUTINE time_zone |
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199 | |
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200 | !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! |
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201 | |
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202 | END MODULE solar |
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