1 | SUBROUTINE calc_liquid_water_content |
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2 | |
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3 | !------------------------------------------------------------------------------! |
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4 | ! Actual revisions: |
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5 | ! ----------------- |
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6 | ! |
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7 | ! |
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8 | ! Former revisions: |
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9 | ! ----------------- |
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10 | ! $Id: calc_liquid_water_content.f90 39 2007-03-01 12:46:59Z raasch $ |
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11 | ! |
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12 | ! 19 2007-02-23 04:53:48Z raasch |
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13 | ! Old comment removed |
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14 | ! |
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15 | ! RCS Log replace by Id keyword, revision history cleaned up |
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16 | ! |
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17 | ! Revision 1.5 2005/03/26 15:22:06 raasch |
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18 | ! Arguments for non-cyclic boundary conditions added to argument list of |
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19 | ! routine exchange_horiz, |
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20 | ! ql calculated for the ghost points, exchange of ghost points removed |
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21 | ! |
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22 | ! Revision 1.1 2000/04/13 14:50:45 schroeter |
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23 | ! Initial revision |
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24 | ! |
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25 | ! |
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26 | ! |
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27 | ! Description: |
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28 | ! ------------ |
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29 | ! Calculation of the liquid water content (0%-or-100%-scheme) |
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30 | !------------------------------------------------------------------------------! |
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31 | |
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32 | |
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33 | USE arrays_3d |
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34 | USE cloud_parameters |
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35 | USE constants |
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36 | USE grid_variables |
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37 | USE indices |
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38 | USE pegrid |
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39 | |
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40 | IMPLICIT NONE |
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41 | |
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42 | INTEGER :: i, j, k |
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43 | |
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44 | REAL :: alpha, e_s, q_s, t_l |
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45 | |
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46 | DO i = nxl-1, nxr+1 |
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47 | DO j = nys-1, nyn+1 |
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48 | DO k = nzb_2d(j,i)+1, nzt |
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49 | |
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50 | ! |
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51 | !-- Compute the liquid water temperature |
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52 | t_l = t_d_pt(k) * pt(k,j,i) |
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53 | |
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54 | ! |
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55 | !-- Compute saturation water vapor pressure at t_l |
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56 | e_s = 610.78 * EXP( 17.269 * ( t_l - 273.16 ) / & |
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57 | ( t_l - 35.86 ) ) |
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58 | |
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59 | ! |
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60 | !-- Compute approximation of saturation humidity |
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61 | q_s = 0.622 * e_s / & |
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62 | ( hydro_press(k) - 0.378 * e_s ) |
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63 | |
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64 | ! |
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65 | !-- Correction factor |
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66 | alpha = 0.622 * l_d_r * l_d_cp / ( t_l * t_l ) |
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67 | |
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68 | ! |
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69 | !-- Correction of the approximated value |
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70 | !-- (see: Cuijpers + Duynkerke, 1993, JAS, 23) |
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71 | q_s = q_s * ( 1.0 + alpha * q(k,j,i) ) / ( 1.0 + alpha * q_s ) |
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72 | |
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73 | ! |
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74 | !-- Compute the liquid water content |
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75 | IF ( ( q(k,j,i) - q_s ) > 0.0 ) THEN |
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76 | ql(k,j,i) = q(k,j,i) - q_s |
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77 | ELSE |
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78 | ql(k,j,i) = 0.0 |
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79 | ENDIF |
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80 | |
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81 | ENDDO |
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82 | ENDDO |
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83 | ENDDO |
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84 | |
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85 | END SUBROUTINE calc_liquid_water_content |
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