1 | ! |
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2 | ! Copyright (c) 2009, Roger Marchand, version 1.2 |
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3 | ! All rights reserved. |
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4 | ! $Revision: 23 $, $Date: 2011-03-31 15:41:37 +0200 (jeu. 31 mars 2011) $ |
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5 | ! $URL: http://cfmip-obs-sim.googlecode.com/svn/stable/v1.4.0/MISR_simulator/MISR_simulator.f $ |
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6 | ! |
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7 | ! Redistribution and use in source and binary forms, with or without modification, are permitted |
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8 | ! provided that the following conditions are met: |
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9 | ! |
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10 | ! * Redistributions of source code must retain the above copyright notice, this list of |
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11 | ! conditions and the following disclaimer. |
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12 | ! * Redistributions in binary form must reproduce the above copyright notice, this list |
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13 | ! of conditions and the following disclaimer in the documentation and/or other materials |
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14 | ! provided with the distribution. |
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15 | ! * Neither the name of the University of Washington nor the names of its contributors may be used |
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16 | ! to endorse or promote products derived from this software without specific prior written permission. |
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17 | ! |
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18 | ! THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, |
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19 | ! BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT |
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20 | ! SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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21 | ! DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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22 | ! INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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23 | ! NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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24 | ! |
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25 | |
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26 | SUBROUTINE MISR_simulator( & |
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27 | npoints, & |
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28 | nlev, & |
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29 | ncol, & |
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30 | sunlit, & |
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31 | zfull, & |
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32 | at, & |
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33 | dtau_s, & |
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34 | dtau_c, & |
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35 | frac_out, & |
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36 | missing_value, & |
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37 | fq_MISR_TAU_v_CTH, & |
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38 | dist_model_layertops, & |
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39 | MISR_mean_ztop, & |
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40 | MISR_cldarea & |
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41 | ) |
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42 | |
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43 | |
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44 | implicit none |
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45 | integer :: n_MISR_CTH |
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46 | parameter(n_MISR_CTH=16) |
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47 | |
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48 | ! ----- |
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49 | ! Input |
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50 | ! ----- |
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51 | |
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52 | INTEGER :: npoints ! if ncol ==1, the number of model points in the horizontal grid |
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53 | ! ! else the number of GCM grid points |
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54 | |
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55 | INTEGER :: nlev ! number of model vertical levels |
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56 | |
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57 | INTEGER :: ncol ! number of model sub columns |
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58 | ! ! (must already be generated in via scops and passed to this |
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59 | ! ! routine via the variable frac_out ) |
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60 | |
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61 | INTEGER :: sunlit(npoints) ! 1 for day points, 0 for night time |
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62 | |
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63 | REAL :: zfull(npoints,nlev) ! height (in meters) of full model levels (i.e. midpoints) |
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64 | ! ! zfull(npoints,1) is top level of model |
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65 | ! ! zfull(npoints,nlev) is bottom level of model (closest point to surface) |
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66 | |
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67 | REAL :: at(npoints,nlev) ! temperature in each model level (K) |
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68 | |
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69 | REAL :: dtau_s(npoints,nlev) ! visible wavelength cloud optical depth ... for "stratiform" condensate |
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70 | ! ! NOTE: this the cloud optical depth of only the |
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71 | ! ! the model cell (i,j) |
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72 | |
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73 | REAL :: dtau_c(npoints,nlev) ! visible wavelength cloud optical depth ... for "convective" condensate |
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74 | ! ! NOTE: this the cloud optical depth of only the |
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75 | ! ! the model cell (i,j) |
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76 | |
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77 | REAL :: frac_out(npoints,ncol,nlev) ! NOTE: only need if columns>1 ... subgrid scheme in use. |
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78 | |
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79 | REAL :: missing_value |
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80 | |
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81 | ! ------ |
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82 | ! Outputs |
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83 | ! ------ |
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84 | |
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85 | REAL :: fq_MISR_TAU_v_CTH(npoints,7,n_MISR_CTH) |
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86 | REAL :: dist_model_layertops(npoints,n_MISR_CTH) |
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87 | REAL :: MISR_cldarea(npoints) ! fractional area coverged by clouds |
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88 | REAL :: MISR_mean_ztop(npoints) ! mean cloud top hieght(m) MISR would observe |
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89 | ! ! NOTE: == 0 if area ==0 |
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90 | |
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91 | |
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92 | ! ------ |
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93 | ! Working variables |
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94 | ! ------ |
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95 | |
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96 | REAL :: tau(npoints,ncol) ! total column optical depth ... |
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97 | |
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98 | INTEGER :: j,ilev,ilev2,ibox,k |
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99 | INTEGER :: itau |
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100 | |
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101 | LOGICAL :: box_cloudy(npoints,ncol) |
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102 | |
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103 | real :: isccp_taumin |
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104 | real :: boxarea |
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105 | real :: tauchk |
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106 | REAL :: box_MISR_ztop(npoints,ncol) ! cloud top hieght(m) MISR would observe |
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107 | |
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108 | integer :: thres_crossed_MISR |
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109 | integer :: loop,iMISR_ztop |
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110 | |
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111 | real :: dtau, cloud_dtau, MISR_penetration_height,ztest |
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112 | |
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113 | real :: MISR_CTH_boundaries(n_MISR_CTH+1) |
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114 | |
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115 | DATA MISR_CTH_boundaries / -99, 0, 0.5, 1, 1.5, 2, 2.5, 3, & |
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116 | 4, 5, 7, 9, 11, 13, 15, 17, 99 / |
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117 | |
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118 | DATA isccp_taumin / 0.3 / |
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119 | |
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120 | tauchk = -1.*log(0.9999999) |
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121 | |
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122 | ! ! |
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123 | ! ! For each GCM cell or horizontal model grid point ... |
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124 | ! ! |
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125 | do j=1,npoints |
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126 | |
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127 | ! ! |
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128 | ! ! estimate distribution of Model layer tops |
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129 | ! ! |
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130 | dist_model_layertops(j,:)=0 |
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131 | |
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132 | do ilev=1,nlev |
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133 | |
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134 | ! ! define location of "layer top" |
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135 | if(ilev.eq.1 .or. ilev.eq.nlev) then |
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136 | ztest=zfull(j,ilev) |
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137 | else |
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138 | ztest=0.5*(zfull(j,ilev)+zfull(j,ilev-1)) |
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139 | endif |
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140 | |
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141 | ! ! find MISR layer that contains this level |
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142 | ! ! note, the first MISR level is "no height" level |
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143 | iMISR_ztop=2 |
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144 | do loop=2,n_MISR_CTH |
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145 | |
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146 | if ( ztest .gt. & |
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147 | 1000*MISR_CTH_boundaries(loop+1) ) then |
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148 | |
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149 | iMISR_ztop=loop+1 |
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150 | endif |
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151 | enddo |
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152 | |
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153 | dist_model_layertops(j,iMISR_ztop)= & |
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154 | dist_model_layertops(j,iMISR_ztop)+1 |
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155 | enddo |
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156 | |
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157 | |
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158 | ! ! |
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159 | ! ! compute total cloud optical depth for each column |
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160 | ! ! |
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161 | do ibox=1,ncol |
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162 | |
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163 | ! ! Initialize tau to zero in each subcolum |
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164 | tau(j,ibox)=0. |
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165 | box_cloudy(j,ibox)=.false. |
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166 | box_MISR_ztop(j,ibox)=0 |
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167 | |
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168 | ! ! initialize threshold detection for each sub column |
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169 | thres_crossed_MISR=0; |
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170 | |
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171 | do ilev=1,nlev |
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172 | |
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173 | dtau=0 |
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174 | |
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175 | if (frac_out(j,ibox,ilev).eq.1) then |
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176 | dtau = dtau_s(j,ilev) |
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177 | endif |
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178 | |
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179 | if (frac_out(j,ibox,ilev).eq.2) then |
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180 | dtau = dtau_c(j,ilev) |
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181 | end if |
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182 | |
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183 | tau(j,ibox)=tau(j,ibox)+ dtau |
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184 | |
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185 | |
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186 | ! ! NOW for MISR .. |
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187 | ! ! if there a cloud ... start the counter ... store this height |
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188 | if(thres_crossed_MISR .eq. 0 .and. dtau .gt. 0.) then |
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189 | |
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190 | ! ! first encountered a "cloud" |
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191 | thres_crossed_MISR=1 |
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192 | cloud_dtau=0 |
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193 | endif |
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194 | |
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195 | if( thres_crossed_MISR .lt. 99 .and. & |
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196 | thres_crossed_MISR .gt. 0 ) then |
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197 | |
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198 | if( dtau .eq. 0.) then |
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199 | |
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200 | ! ! we have come to the end of the current cloud |
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201 | ! ! layer without yet selecting a CTH boundary. |
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202 | ! ! ... restart cloud tau counter |
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203 | cloud_dtau=0 |
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204 | else |
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205 | ! ! add current optical depth to count for |
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206 | ! ! the current cloud layer |
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207 | cloud_dtau=cloud_dtau+dtau |
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208 | endif |
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209 | |
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210 | ! ! if the cloud is continuous but optically thin (< 1) |
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211 | ! ! from above the current layer cloud top to the current level |
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212 | ! ! then MISR will like see a top below the top of the current |
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213 | ! ! layer |
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214 | if( dtau.gt.0 .and. (cloud_dtau-dtau) .lt. 1) then |
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215 | |
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216 | if(dtau .lt. 1 .or. ilev.eq.1 .or. ilev.eq.nlev) then |
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217 | |
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218 | ! ! MISR will likely penetrate to some point |
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219 | ! ! within this layer ... the middle |
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220 | MISR_penetration_height=zfull(j,ilev) |
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221 | |
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222 | else |
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223 | ! ! take the OD = 1.0 level into this layer |
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224 | MISR_penetration_height= & |
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225 | 0.5*(zfull(j,ilev)+zfull(j,ilev-1)) - & |
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226 | 0.5*(zfull(j,ilev-1)-zfull(j,ilev+1)) & |
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227 | /dtau |
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228 | endif |
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229 | |
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230 | box_MISR_ztop(j,ibox)=MISR_penetration_height |
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231 | |
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232 | endif |
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233 | |
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234 | ! ! check for a distinctive water layer |
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235 | if(dtau .gt. 1 .and. at(j,ilev).gt.273 ) then |
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236 | |
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237 | ! ! must be a water cloud ... |
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238 | ! ! take this as CTH level |
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239 | thres_crossed_MISR=99 |
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240 | endif |
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241 | |
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242 | ! ! if the total column optical depth is "large" than |
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243 | ! ! MISR can't seen anything else ... set current point as CTH level |
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244 | if(tau(j,ibox) .gt. 5) then |
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245 | |
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246 | thres_crossed_MISR=99 |
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247 | endif |
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248 | |
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249 | endif ! MISR CTH booundary not set |
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250 | |
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251 | enddo !ilev - loop over vertical levesl |
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252 | |
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253 | ! ! written by roj 5/2006 |
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254 | ! ! check to see if there was a cloud for which we didn't |
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255 | ! ! set a MISR cloud top boundary |
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256 | if( thres_crossed_MISR .eq. 1) then |
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257 | |
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258 | ! ! if the cloud has a total optical depth of greater |
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259 | ! ! than ~ 0.5 MISR will still likely pick up this cloud |
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260 | ! ! with a height near the true cloud top |
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261 | ! ! otherwise there should be no CTH |
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262 | if( tau(j,ibox) .gt. 0.5) then |
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263 | |
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264 | ! ! keep MISR detected CTH |
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265 | |
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266 | elseif(tau(j,ibox) .gt. 0.2) then |
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267 | |
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268 | ! ! MISR may detect but wont likley have a good height |
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269 | box_MISR_ztop(j,ibox)=-1 |
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270 | |
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271 | else |
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272 | ! ! MISR not likely to even detect. |
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273 | ! ! so set as not cloudy |
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274 | box_MISR_ztop(j,ibox)=0 |
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275 | |
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276 | endif |
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277 | |
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278 | endif |
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279 | |
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280 | enddo ! loop of subcolumns |
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281 | enddo ! loop of gridpoints |
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282 | |
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283 | |
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284 | ! ! |
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285 | ! ! Modify MISR CTH for satellite spatial / pattern matcher effects |
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286 | ! ! |
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287 | ! ! Code in this region added by roj 5/2006 to account |
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288 | ! ! for spatial effect of the MISR pattern matcher. |
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289 | ! ! Basically, if a column is found between two neighbors |
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290 | ! ! at the same CTH, and that column has no hieght or |
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291 | ! ! a lower CTH, THEN misr will tend to but place the |
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292 | ! ! odd column at the same height as it neighbors. |
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293 | ! ! |
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294 | ! ! This setup assumes the columns represent a about a 1 to 4 km scale |
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295 | ! ! it will need to be modified significantly, otherwise |
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296 | if(ncol.eq.1) then |
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297 | |
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298 | ! ! adjust based on neightboring points ... i.e. only 2D grid was input |
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299 | do j=2,npoints-1 |
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300 | |
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301 | if(box_MISR_ztop(j-1,1).gt.0 .and. & |
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302 | box_MISR_ztop(j+1,1).gt.0 ) then |
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303 | |
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304 | if( abs( box_MISR_ztop(j-1,1) - & |
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305 | box_MISR_ztop(j+1,1) ) .lt. 500 & |
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306 | .and. & |
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307 | box_MISR_ztop(j,1) .lt. & |
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308 | box_MISR_ztop(j+1,1) ) then |
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309 | |
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310 | box_MISR_ztop(j,1) = & |
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311 | box_MISR_ztop(j+1,1) |
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312 | endif |
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313 | |
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314 | endif |
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315 | enddo |
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316 | else |
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317 | |
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318 | ! ! adjust based on neighboring subcolumns .... |
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319 | do ibox=2,ncol-1 |
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320 | |
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321 | if(box_MISR_ztop(1,ibox-1).gt.0 .and. & |
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322 | box_MISR_ztop(1,ibox+1).gt.0 ) then |
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323 | |
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324 | if( abs( box_MISR_ztop(1,ibox-1) - & |
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325 | box_MISR_ztop(1,ibox+1) ) .lt. 500 & |
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326 | .and. & |
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327 | box_MISR_ztop(1,ibox) .lt. & |
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328 | box_MISR_ztop(1,ibox+1) ) then |
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329 | |
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330 | box_MISR_ztop(1,ibox) = & |
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331 | box_MISR_ztop(1,ibox+1) |
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332 | endif |
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333 | |
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334 | endif |
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335 | enddo |
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336 | |
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337 | endif |
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338 | |
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339 | ! ! |
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340 | ! ! DETERMINE CLOUD TYPE FREQUENCIES |
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341 | ! ! |
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342 | ! ! Now that ztop and tau have been determined, |
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343 | ! ! determine amount of each cloud type |
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344 | boxarea=1./real(ncol) |
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345 | do j=1,npoints |
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346 | |
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347 | ! ! reset frequencies -- modified loop structure, roj 5/2006 |
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348 | do ilev=1,7 ! "tau loop" |
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349 | do ilev2=1,n_MISR_CTH |
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350 | fq_MISR_TAU_v_CTH(j,ilev,ilev2)=0. |
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351 | enddo |
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352 | enddo |
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353 | |
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354 | MISR_cldarea(j)=0. |
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355 | MISR_mean_ztop(j)=0. |
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356 | |
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357 | do ibox=1,ncol |
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358 | |
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359 | if (tau(j,ibox) .gt. (tauchk)) then |
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360 | box_cloudy(j,ibox)=.true. |
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361 | endif |
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362 | |
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363 | itau = 0 |
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364 | |
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365 | if (box_cloudy(j,ibox)) then |
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366 | |
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367 | ! !determine optical depth category |
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368 | if (tau(j,ibox) .lt. isccp_taumin) then |
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369 | itau=1 |
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370 | else if (tau(j,ibox) .ge. isccp_taumin & |
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371 | .and. tau(j,ibox) .lt. 1.3) then |
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372 | itau=2 |
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373 | else if (tau(j,ibox) .ge. 1.3 & |
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374 | .and. tau(j,ibox) .lt. 3.6) then |
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375 | itau=3 |
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376 | else if (tau(j,ibox) .ge. 3.6 & |
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377 | .and. tau(j,ibox) .lt. 9.4) then |
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378 | itau=4 |
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379 | else if (tau(j,ibox) .ge. 9.4 & |
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380 | .and. tau(j,ibox) .lt. 23.) then |
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381 | itau=5 |
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382 | else if (tau(j,ibox) .ge. 23. & |
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383 | .and. tau(j,ibox) .lt. 60.) then |
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384 | itau=6 |
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385 | else if (tau(j,ibox) .ge. 60.) then |
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386 | itau=7 |
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387 | endif |
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388 | |
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389 | endif |
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390 | |
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391 | ! ! update MISR histograms and summary metrics - roj 5/2005 |
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392 | if (sunlit(j).eq.1) then |
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393 | |
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394 | ! !if cloudy added by roj 5/2005 |
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395 | if( box_MISR_ztop(j,ibox).eq.0) then |
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396 | |
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397 | ! ! no cloud detected |
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398 | iMISR_ztop=0 |
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399 | |
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400 | elseif( box_MISR_ztop(j,ibox).eq.-1) then |
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401 | |
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402 | ! ! cloud can be detected but too thin to get CTH |
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403 | iMISR_ztop=1 |
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404 | |
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405 | fq_MISR_TAU_v_CTH(j,itau,iMISR_ztop)= & |
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406 | fq_MISR_TAU_v_CTH(j,itau,iMISR_ztop) + boxarea |
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407 | |
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408 | else |
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409 | |
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410 | ! ! |
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411 | ! ! determine index for MISR bin set |
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412 | ! ! |
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413 | |
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414 | iMISR_ztop=2 |
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415 | |
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416 | do loop=2,n_MISR_CTH |
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417 | |
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418 | if ( box_MISR_ztop(j,ibox) .gt. & |
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419 | 1000*MISR_CTH_boundaries(loop+1) ) then |
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420 | |
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421 | iMISR_ztop=loop+1 |
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422 | |
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423 | endif |
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424 | enddo |
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425 | |
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426 | if(box_cloudy(j,ibox)) then |
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427 | |
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428 | ! ! there is an isccp clouds so itau(j) is defined |
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429 | fq_MISR_TAU_v_CTH(j,itau,iMISR_ztop)= & |
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430 | fq_MISR_TAU_v_CTH(j,itau,iMISR_ztop) + boxarea |
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431 | |
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432 | else |
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433 | ! ! MISR CTH resolution is trying to fill in a |
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434 | ! ! broken cloud scene where there is no condensate. |
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435 | ! ! The MISR CTH-1D-OD product will only put in a cloud |
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436 | ! ! if the MISR cloud mask indicates cloud. |
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437 | ! ! therefore we will not include this column in the histogram |
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438 | ! ! in reality aerosoal and 3D effects or bright surfaces |
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439 | ! ! could fool the MISR cloud mask |
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440 | |
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441 | ! ! the alternative is to count as very thin cloud ?? |
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442 | ! fq_MISR_TAU_v_CTH(1,iMISR_ztop)= |
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443 | ! & fq_MISR_TAU_v_CTH(1,iMISR_ztop) + boxarea |
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444 | endif |
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445 | |
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446 | |
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447 | MISR_mean_ztop(j)=MISR_mean_ztop(j)+ & |
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448 | box_MISR_ztop(j,ibox)*boxarea |
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449 | |
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450 | MISR_cldarea(j)=MISR_cldarea(j) + boxarea |
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451 | |
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452 | endif |
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453 | else |
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454 | ! ! Set to issing data. A. Bodas - 14/05/2010 |
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455 | do loop=1,n_MISR_CTH |
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456 | do k=1,7 |
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457 | fq_MISR_TAU_v_CTH(j,k,loop) = missing_value |
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458 | enddo |
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459 | dist_model_layertops(j,loop) = missing_value |
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460 | enddo |
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461 | MISR_cldarea(j) = missing_value |
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462 | MISR_mean_ztop(npoints) = missing_value |
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463 | |
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464 | endif ! is sunlight ? |
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465 | |
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466 | enddo ! ibox - loop over subcolumns |
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467 | |
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468 | if( MISR_cldarea(j) .gt. 0.) then |
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469 | MISR_mean_ztop(j)= MISR_mean_ztop(j) / MISR_cldarea(j) ! roj 5/2006 |
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470 | endif |
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471 | |
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472 | enddo ! loop over grid points |
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473 | |
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474 | return |
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475 | end subroutine misr_simulator |
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