source: palm/trunk/SOURCE/calc_liquid_water_content.f90 @ 484

Last change on this file since 484 was 484, checked in by raasch, 12 years ago

typo in file headers removed

  • Property svn:keywords set to Id
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1 SUBROUTINE calc_liquid_water_content
2
3!------------------------------------------------------------------------------!
4! Current revisions:
5! -----------------
6!
7!
8! Former revisions:
9! -----------------
10! $Id: calc_liquid_water_content.f90 484 2010-02-05 07:36:54Z raasch $
11!
12! 95 2007-06-02 16:48:38Z raasch
13! hydro_press renamed hyp
14!
15! 19 2007-02-23 04:53:48Z raasch
16! Old comment removed
17!
18! RCS Log replace by Id keyword, revision history cleaned up
19!
20! Revision 1.5  2005/03/26 15:22:06  raasch
21! Arguments for non-cyclic boundary conditions added to argument list of
22! routine exchange_horiz,
23! ql calculated for the ghost points, exchange of ghost points removed
24!
25! Revision 1.1  2000/04/13 14:50:45  schroeter
26! Initial revision
27!
28!
29!
30! Description:
31! ------------
32! Calculation of the liquid water content (0%-or-100%-scheme)
33!------------------------------------------------------------------------------!
34
35
36    USE arrays_3d
37    USE cloud_parameters
38    USE constants
39    USE grid_variables
40    USE indices
41    USE pegrid
42
43    IMPLICIT NONE
44
45    INTEGER :: i, j, k
46
47    REAL :: alpha, e_s, q_s, t_l
48
49    DO  i = nxl-1, nxr+1
50       DO  j = nys-1, nyn+1
51          DO  k = nzb_2d(j,i)+1, nzt
52
53!
54!--          Compute the liquid water temperature
55             t_l = t_d_pt(k) * pt(k,j,i)
56
57!
58!--          Compute saturation water vapor pressure at t_l
59             e_s = 610.78 * EXP( 17.269 * ( t_l - 273.16 ) / &
60                                          ( t_l - 35.86 ) )
61
62!
63!--          Compute approximation of saturation humidity
64             q_s = 0.622 * e_s / ( hyp(k) - 0.378 * e_s )
65
66!
67!--          Correction factor
68             alpha = 0.622 * l_d_r * l_d_cp / ( t_l * t_l )
69
70!
71!--          Correction of the approximated value
72!--          (see: Cuijpers + Duynkerke, 1993, JAS, 23)
73             q_s = q_s * ( 1.0 + alpha * q(k,j,i) ) / ( 1.0 + alpha * q_s )
74
75!
76!--          Compute the liquid water content
77             IF ( ( q(k,j,i) - q_s ) > 0.0 ) THEN
78                ql(k,j,i) = q(k,j,i) - q_s
79             ELSE
80                ql(k,j,i) = 0.0 
81             ENDIF
82
83          ENDDO
84       ENDDO
85    ENDDO
86   
87 END SUBROUTINE calc_liquid_water_content
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