1 | SUBROUTINE calc_liquid_water_content |
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2 | |
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3 | !--------------------------------------------------------------------------------! |
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4 | ! This file is part of PALM. |
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5 | ! |
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6 | ! PALM is free software: you can redistribute it and/or modify it under the terms |
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7 | ! of the GNU General Public License as published by the Free Software Foundation, |
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8 | ! either version 3 of the License, or (at your option) any later version. |
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9 | ! |
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10 | ! PALM is distributed in the hope that it will be useful, but WITHOUT ANY |
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11 | ! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR |
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12 | ! A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
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13 | ! |
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14 | ! You should have received a copy of the GNU General Public License along with |
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15 | ! PALM. If not, see <http://www.gnu.org/licenses/>. |
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16 | ! |
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17 | ! Copyright 1997-2012 Leibniz University Hannover |
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18 | !--------------------------------------------------------------------------------! |
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19 | ! |
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20 | ! Current revisions: |
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21 | ! ----------------- |
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22 | ! |
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23 | ! Former revisions: |
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24 | ! ----------------- |
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25 | ! $Id: calc_liquid_water_content.f90 1054 2012-11-13 17:30:09Z hoffmann $ |
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26 | ! |
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27 | ! 1053 2012-11-13 17:11:03Z hoffmann |
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28 | ! description expanded to the two-moment cloud scheme |
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29 | ! |
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30 | ! 1036 2012-10-22 13:43:42Z raasch |
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31 | ! code put under GPL (PALM 3.9) |
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32 | ! |
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33 | ! 667 2010-12-23 12:06:00Z suehring/gyschka |
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34 | ! nxl-1, nxr+1, nys-1, nyn+1 replaced by nxlg, nxrg, nysg, nyng |
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35 | ! |
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36 | ! 95 2007-06-02 16:48:38Z raasch |
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37 | ! hydro_press renamed hyp |
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38 | ! |
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39 | ! 19 2007-02-23 04:53:48Z raasch |
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40 | ! Old comment removed |
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41 | ! |
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42 | ! RCS Log replace by Id keyword, revision history cleaned up |
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43 | ! |
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44 | ! Revision 1.5 2005/03/26 15:22:06 raasch |
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45 | ! Arguments for non-cyclic boundary conditions added to argument list of |
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46 | ! routine exchange_horiz, |
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47 | ! ql calculated for the ghost points, exchange of ghost points removed |
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48 | ! |
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49 | ! Revision 1.1 2000/04/13 14:50:45 schroeter |
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50 | ! Initial revision |
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51 | ! |
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52 | ! |
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53 | ! |
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54 | ! Description: |
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55 | ! ------------ |
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56 | ! Calculation of the liquid water content (0%-or-100%-scheme). This scheme is |
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57 | ! used by the one and the two moment cloud physics scheme. Using the two moment |
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58 | ! scheme, this calculation results in the cloud water content. |
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59 | !------------------------------------------------------------------------------! |
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60 | |
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61 | |
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62 | USE arrays_3d |
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63 | USE cloud_parameters |
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64 | USE constants |
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65 | USE grid_variables |
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66 | USE indices |
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67 | USE pegrid |
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68 | |
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69 | IMPLICIT NONE |
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70 | |
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71 | INTEGER :: i, j, k |
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72 | |
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73 | REAL :: alpha, e_s, q_s, t_l |
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74 | |
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75 | DO i = nxlg, nxrg |
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76 | DO j = nysg, nyng |
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77 | DO k = nzb_2d(j,i)+1, nzt |
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78 | |
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79 | ! |
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80 | !-- Compute the liquid water temperature |
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81 | t_l = t_d_pt(k) * pt(k,j,i) |
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82 | |
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83 | ! |
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84 | !-- Compute saturation water vapor pressure at t_l |
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85 | e_s = 610.78 * EXP( 17.269 * ( t_l - 273.16 ) / & |
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86 | ( t_l - 35.86 ) ) |
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87 | |
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88 | ! |
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89 | !-- Compute approximation of saturation humidity |
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90 | q_s = 0.622 * e_s / ( hyp(k) - 0.378 * e_s ) |
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91 | |
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92 | ! |
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93 | !-- Correction factor |
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94 | alpha = 0.622 * l_d_r * l_d_cp / ( t_l * t_l ) |
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95 | |
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96 | ! |
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97 | !-- Correction of the approximated value |
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98 | !-- (see: Cuijpers + Duynkerke, 1993, JAS, 23) |
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99 | q_s = q_s * ( 1.0 + alpha * q(k,j,i) ) / ( 1.0 + alpha * q_s ) |
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100 | |
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101 | ! |
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102 | !-- Compute the liquid water content |
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103 | IF ( ( q(k,j,i) - q_s ) > 0.0 ) THEN |
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104 | ql(k,j,i) = q(k,j,i) - q_s |
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105 | ELSE |
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106 | ql(k,j,i) = 0.0 |
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107 | ENDIF |
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108 | |
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109 | ENDDO |
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110 | ENDDO |
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111 | ENDDO |
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112 | |
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113 | END SUBROUTINE calc_liquid_water_content |
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