1 | !********************************************************************** |
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2 | ! Copyright 1998,1999,2000,2001,2002,2005,2007,2008,2009,2010 * |
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3 | ! Andreas Stohl, Petra Seibert, A. Frank, Gerhard Wotawa, * |
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4 | ! Caroline Forster, Sabine Eckhardt, John Burkhart, Harald Sodemann * |
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5 | ! * |
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6 | ! This file is part of FLEXPART. * |
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7 | ! * |
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8 | ! FLEXPART is free software: you can redistribute it and/or modify * |
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9 | ! it under the terms of the GNU General Public License as published by* |
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10 | ! the Free Software Foundation, either version 3 of the License, or * |
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11 | ! (at your option) any later version. * |
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12 | ! * |
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13 | ! FLEXPART is distributed in the hope that it will be useful, * |
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14 | ! but WITHOUT ANY WARRANTY; without even the implied warranty of * |
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15 | ! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
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16 | ! GNU General Public License for more details. * |
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17 | ! * |
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18 | ! You should have received a copy of the GNU General Public License * |
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19 | ! along with FLEXPART. If not, see <http://www.gnu.org/licenses/>. * |
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20 | !********************************************************************** |
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21 | |
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22 | subroutine redist (ipart,ktop,ipconv) |
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23 | |
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24 | !************************************************************************** |
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25 | ! Do the redistribution of particles due to convection |
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26 | ! This subroutine is called for each particle which is assigned |
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27 | ! a new vertical position randomly, based on the convective redistribution |
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28 | ! matrix |
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29 | !************************************************************************** |
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30 | |
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31 | ! Petra Seibert, Feb 2001, Apr 2001, May 2001, Jan 2002, Nov 2002 and |
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32 | ! Andreas Frank, Nov 2002 |
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33 | |
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34 | ! Caroline Forster: November 2004 - February 2005 |
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35 | |
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36 | use par_mod |
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37 | use com_mod |
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38 | use conv_mod |
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39 | |
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40 | implicit none |
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41 | |
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42 | real,parameter :: const=r_air/ga |
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43 | integer :: ipart, ktop,ipconv |
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44 | integer :: k, kz, levnew, levold |
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45 | real,save :: uvzlev(nuvzmax) |
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46 | real :: wsub(nuvzmax) |
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47 | real :: totlevmass, wsubpart |
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48 | real :: temp_levold,temp_levold1 |
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49 | real :: sub_levold,sub_levold1 |
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50 | real :: pint, pold, rn, tv, tvold, dlevfrac |
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51 | real :: ew,ran3, ztold,ffraction |
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52 | real :: tv1, tv2, dlogp, dz, dz1, dz2 |
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53 | integer :: iseed = -88 |
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54 | |
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55 | ! ipart ... number of particle to be treated |
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56 | |
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57 | ipconv=1 |
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58 | |
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59 | ! determine height of the eta half-levels (uvzlev) |
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60 | ! do that only once for each grid column |
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61 | ! i.e. when ktop.eq.1 |
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62 | !************************************************************** |
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63 | |
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64 | if (ktop .le. 1) then |
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65 | |
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66 | tvold=tt2conv*(1.+0.378*ew(td2conv)/psconv) |
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67 | pold=psconv |
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68 | uvzlev(1)=0. |
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69 | |
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70 | pint = phconv(2) |
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71 | ! determine next virtual temperatures |
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72 | tv1 = tconv(1)*(1.+0.608*qconv(1)) |
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73 | tv2 = tconv(2)*(1.+0.608*qconv(2)) |
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74 | ! interpolate virtual temperature to half-level |
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75 | tv = tv1 + (tv2-tv1)*(pconv(1)-phconv(2))/(pconv(1)-pconv(2)) |
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76 | if (abs(tv-tvold).gt.0.2) then |
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77 | uvzlev(2) = uvzlev(1) + & |
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78 | const*log(pold/pint)* & |
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79 | (tv-tvold)/log(tv/tvold) |
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80 | else |
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81 | uvzlev(2) = uvzlev(1)+ & |
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82 | const*log(pold/pint)*tv |
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83 | endif |
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84 | tvold=tv |
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85 | tv1=tv2 |
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86 | pold=pint |
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87 | |
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88 | ! integrate profile (calculation of height agl of eta layers) as required |
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89 | do kz = 3, nconvtop+1 |
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90 | ! note that variables defined in calcmatrix.f (pconv,tconv,qconv) |
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91 | ! start at the first real ECMWF model level whereas kz and |
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92 | ! thus uvzlev(kz) starts at the surface. uvzlev is defined at the |
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93 | ! half-levels (between the tconv, qconv etc. values !) |
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94 | ! Thus, uvzlev(kz) is the lower boundary of the tconv(kz) cell. |
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95 | pint = phconv(kz) |
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96 | ! determine next virtual temperatures |
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97 | tv2 = tconv(kz)*(1.+0.608*qconv(kz)) |
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98 | ! interpolate virtual temperature to half-level |
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99 | tv = tv1 + (tv2-tv1)*(pconv(kz-1)-phconv(kz))/ & |
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100 | (pconv(kz-1)-pconv(kz)) |
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101 | if (abs(tv-tvold).gt.0.2) then |
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102 | uvzlev(kz) = uvzlev(kz-1) + & |
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103 | const*log(pold/pint)* & |
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104 | (tv-tvold)/log(tv/tvold) |
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105 | else |
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106 | uvzlev(kz) = uvzlev(kz-1)+ & |
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107 | const*log(pold/pint)*tv |
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108 | endif |
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109 | tvold=tv |
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110 | tv1=tv2 |
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111 | pold=pint |
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112 | |
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113 | end do |
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114 | |
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115 | ktop = 2 |
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116 | |
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117 | endif ! (if ktop .le. 1) then |
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118 | |
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119 | ! determine vertical grid position of particle in the eta system |
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120 | !**************************************************************** |
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121 | |
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122 | ztold = ztra1(abs(ipart)) |
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123 | ! find old particle grid position |
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124 | do kz = 2, nconvtop |
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125 | if (uvzlev(kz) .ge. ztold ) then |
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126 | levold = kz-1 |
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127 | goto 30 |
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128 | endif |
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129 | end do |
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130 | |
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131 | ! Particle is above the potentially convective domain. Skip it. |
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132 | goto 90 |
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133 | |
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134 | 30 continue |
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135 | |
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136 | ! now redistribute particles |
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137 | !**************************** |
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138 | |
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139 | ! Choose a random number and find corresponding level of destination |
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140 | ! Random numbers to be evenly distributed in [0,1] |
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141 | |
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142 | rn = ran3(iseed) |
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143 | |
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144 | ! initialize levnew |
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145 | |
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146 | levnew = levold |
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147 | |
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148 | ffraction = 0. |
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149 | totlevmass=dpr(levold)/ga |
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150 | do k = 1,nconvtop |
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151 | ! for backward runs use the transposed matrix |
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152 | if (ldirect.eq.1) then |
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153 | ffraction=ffraction+fmassfrac(levold,k) & |
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154 | /totlevmass |
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155 | else |
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156 | ffraction=ffraction+fmassfrac(k,levold) & |
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157 | /totlevmass |
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158 | endif |
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159 | if (rn.le.ffraction) then |
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160 | levnew=k |
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161 | ! avoid division by zero or a too small number |
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162 | ! if division by zero or a too small number happens the |
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163 | ! particle is assigned to the center of the grid cell |
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164 | if (ffraction.gt.1.e-20) then |
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165 | if (ldirect.eq.1) then |
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166 | dlevfrac = (ffraction-rn) / fmassfrac(levold,k) * totlevmass |
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167 | else |
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168 | dlevfrac = (ffraction-rn) / fmassfrac(k,levold) * totlevmass |
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169 | endif |
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170 | else |
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171 | dlevfrac = 0.5 |
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172 | endif |
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173 | goto 40 |
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174 | endif |
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175 | end do |
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176 | |
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177 | 40 continue |
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178 | |
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179 | ! now assign new position to particle |
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180 | |
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181 | if (levnew.le.nconvtop) then |
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182 | if (levnew.eq.levold) then |
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183 | ztra1(abs(ipart)) = ztold |
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184 | else |
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185 | dlogp = (1.-dlevfrac)* & |
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186 | (log(phconv(levnew+1))-log(phconv(levnew))) |
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187 | pint = log(phconv(levnew))+dlogp |
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188 | dz1 = pint - log(phconv(levnew)) |
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189 | dz2 = log(phconv(levnew+1)) - pint |
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190 | dz = dz1 + dz2 |
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191 | ztra1(abs(ipart)) = (uvzlev(levnew)*dz2+uvzlev(levnew+1)*dz1)/dz |
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192 | if (ztra1(abs(ipart)).lt.0.) & |
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193 | ztra1(abs(ipart))=-1.*ztra1(abs(ipart)) |
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194 | if (ipconv.gt.0) ipconv=-1 |
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195 | endif |
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196 | endif |
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197 | |
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198 | ! displace particle according to compensating subsidence |
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199 | ! this is done to those particles, that were not redistributed |
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200 | ! by the matrix |
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201 | !************************************************************** |
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202 | |
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203 | if (levnew.le.nconvtop.and.levnew.eq.levold) then |
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204 | |
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205 | ztold = ztra1(abs(ipart)) |
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206 | |
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207 | ! determine compensating vertical velocity at the levels |
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208 | ! above and below the particel position |
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209 | ! increase compensating subsidence by the fraction that |
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210 | ! is displaced by convection to this level |
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211 | |
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212 | if (levold.gt.1) then |
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213 | temp_levold = tconv(levold-1) + & |
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214 | (tconv(levold)-tconv(levold-1)) & |
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215 | *(pconv(levold-1)-phconv(levold))/ & |
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216 | (pconv(levold-1)-pconv(levold)) |
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217 | sub_levold = sub(levold)/(1.-sub(levold)/dpr(levold)*ga) |
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218 | wsub(levold)=-1.*sub_levold*r_air*temp_levold/(phconv(levold)) |
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219 | else |
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220 | wsub(levold)=0. |
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221 | endif |
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222 | |
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223 | temp_levold1 = tconv(levold) + & |
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224 | (tconv(levold+1)-tconv(levold)) & |
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225 | *(pconv(levold)-phconv(levold+1))/ & |
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226 | (pconv(levold)-pconv(levold+1)) |
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227 | sub_levold1 = sub(levold+1)/(1.-sub(levold+1)/dpr(levold+1)*ga) |
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228 | wsub(levold+1)=-1.*sub_levold1*r_air*temp_levold1/ & |
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229 | (phconv(levold+1)) |
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230 | |
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231 | ! interpolate wsub to the vertical particle position |
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232 | |
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233 | dz1 = ztold - uvzlev(levold) |
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234 | dz2 = uvzlev(levold+1) - ztold |
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235 | dz = dz1 + dz2 |
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236 | |
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237 | wsubpart = (dz2*wsub(levold)+dz1*wsub(levold+1))/dz |
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238 | ztra1(abs(ipart)) = ztold+wsubpart*real(lsynctime) |
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239 | if (ztra1(abs(ipart)).lt.0.) then |
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240 | ztra1(abs(ipart))=-1.*ztra1(abs(ipart)) |
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241 | endif |
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242 | |
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243 | endif !(levnew.le.nconvtop.and.levnew.eq.levold) |
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244 | |
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245 | ! Maximum altitude .5 meter below uppermost model level |
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246 | !******************************************************* |
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247 | |
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248 | 90 continue |
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249 | |
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250 | if (ztra1(abs(ipart)) .gt. height(nz)-0.5) & |
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251 | ztra1(abs(ipart)) = height(nz)-0.5 |
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252 | |
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253 | end subroutine redist |
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