source: palm/trunk/SOURCE/calc_liquid_water_content.f90 @ 4

Last change on this file since 4 was 4, checked in by raasch, 15 years ago

Id keyword set as property for all *.f90 files

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