| 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 98 2007-06-21 09:36:33Z raasch $ |
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| 11 | ! |
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| 12 | ! 95 2007-06-02 16:48:38Z raasch |
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| 13 | ! hydro_press renamed hyp |
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| 14 | ! |
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| 15 | ! 19 2007-02-23 04:53:48Z raasch |
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| 16 | ! Old comment removed |
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| 17 | ! |
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| 18 | ! RCS Log replace by Id keyword, revision history cleaned up |
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| 19 | ! |
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| 20 | ! Revision 1.5 2005/03/26 15:22:06 raasch |
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| 21 | ! Arguments for non-cyclic boundary conditions added to argument list of |
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| 22 | ! routine exchange_horiz, |
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| 23 | ! ql calculated for the ghost points, exchange of ghost points removed |
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| 24 | ! |
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| 25 | ! Revision 1.1 2000/04/13 14:50:45 schroeter |
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| 26 | ! Initial revision |
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| 27 | ! |
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| 28 | ! |
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| 29 | ! |
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| 30 | ! Description: |
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| 31 | ! ------------ |
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| 32 | ! Calculation of the liquid water content (0%-or-100%-scheme) |
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| 33 | !------------------------------------------------------------------------------! |
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| 34 | |
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| 35 | |
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| 36 | USE arrays_3d |
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| 37 | USE cloud_parameters |
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| 38 | USE constants |
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| 39 | USE grid_variables |
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| 40 | USE indices |
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| 41 | USE pegrid |
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| 42 | |
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| 43 | IMPLICIT NONE |
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| 44 | |
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| 45 | INTEGER :: i, j, k |
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| 46 | |
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| 47 | REAL :: alpha, e_s, q_s, t_l |
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| 48 | |
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| 49 | DO i = nxl-1, nxr+1 |
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| 50 | DO j = nys-1, nyn+1 |
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| 51 | DO k = nzb_2d(j,i)+1, nzt |
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| 52 | |
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| 53 | ! |
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| 54 | !-- Compute the liquid water temperature |
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| 55 | t_l = t_d_pt(k) * pt(k,j,i) |
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| 56 | |
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| 57 | ! |
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| 58 | !-- Compute saturation water vapor pressure at t_l |
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| 59 | e_s = 610.78 * EXP( 17.269 * ( t_l - 273.16 ) / & |
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| 60 | ( t_l - 35.86 ) ) |
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| 61 | |
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| 62 | ! |
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| 63 | !-- Compute approximation of saturation humidity |
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| 64 | q_s = 0.622 * e_s / ( hyp(k) - 0.378 * e_s ) |
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| 65 | |
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| 66 | ! |
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| 67 | !-- Correction factor |
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| 68 | alpha = 0.622 * l_d_r * l_d_cp / ( t_l * t_l ) |
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| 69 | |
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| 70 | ! |
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| 71 | !-- Correction of the approximated value |
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| 72 | !-- (see: Cuijpers + Duynkerke, 1993, JAS, 23) |
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| 73 | q_s = q_s * ( 1.0 + alpha * q(k,j,i) ) / ( 1.0 + alpha * q_s ) |
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| 74 | |
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| 75 | ! |
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| 76 | !-- Compute the liquid water content |
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| 77 | IF ( ( q(k,j,i) - q_s ) > 0.0 ) THEN |
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| 78 | ql(k,j,i) = q(k,j,i) - q_s |
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| 79 | ELSE |
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| 80 | ql(k,j,i) = 0.0 |
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| 81 | ENDIF |
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| 82 | |
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| 83 | ENDDO |
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| 84 | ENDDO |
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| 85 | ENDDO |
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| 86 | |
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| 87 | END SUBROUTINE calc_liquid_water_content |
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