source: palm/trunk/SOURCE/calc_liquid_water_content.f90 @ 2233

Last change on this file since 2233 was 2233, checked in by suehring, 4 years ago

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1!> @file calc_liquid_water_content.f90
2!------------------------------------------------------------------------------!
3! This file is part of PALM.
4!
5! PALM is free software: you can redistribute it and/or modify it under the
6! terms of the GNU General Public License as published by the Free Software
7! Foundation, either version 3 of the License, or (at your option) any later
8! version.
9!
10! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
11! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12! A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
13!
14! You should have received a copy of the GNU General Public License along with
15! PALM. If not, see <http://www.gnu.org/licenses/>.
16!
17! Copyright 1997-2017 Leibniz Universitaet Hannover
18!------------------------------------------------------------------------------!
19!
20! Current revisions:
21! -----------------
22!
23!
24! Former revisions:
25! -----------------
26! $Id: calc_liquid_water_content.f90 2233 2017-05-30 18:08:54Z suehring $
27!
28! 2232 2017-05-30 17:47:52Z suehring
29! Adjustments to new topography concept
30!
31! 2000 2016-08-20 18:09:15Z knoop
32! Forced header and separation lines into 80 columns
33!
34! 1822 2016-04-07 07:49:42Z hoffmann
35! icloud_scheme removed. microphysics_seifert added.
36!
37! 1682 2015-10-07 23:56:08Z knoop
38! Code annotations made doxygen readable
39!
40! 1353 2014-04-08 15:21:23Z heinze
41! REAL constants provided with KIND-attribute
42!
43! 1320 2014-03-20 08:40:49Z raasch
44! ONLY-attribute added to USE-statements,
45! kind-parameters added to all INTEGER and REAL declaration statements,
46! kinds are defined in new module kinds,
47! revision history before 2012 removed,
48! comment fields (!:) to be used for variable explanations added to
49! all variable declaration statements
50!
51! 1253 2013-11-07 10:48:12Z fricke
52! Bugfix: q is set to qr in case that q is smaller than qr
53!
54! 1115 2013-03-26 18:16:16Z hoffmann
55! drizzle can be used independently from precipitation
56!
57! 1053 2012-11-13 17:11:03Z hoffmann
58! description expanded to the two-moment cloud scheme
59!
60! 1036 2012-10-22 13:43:42Z raasch
61! code put under GPL (PALM 3.9)
62!
63! Revision 1.1  2000/04/13 14:50:45  schroeter
64! Initial revision
65!
66!
67!
68! Description:
69! ------------
70!> Calculation of the liquid water content (0%-or-100%-scheme). This scheme is
71!> used by the one and the two moment cloud physics scheme. Using the two moment
72!> scheme, this calculation results in the cloud water content.
73!------------------------------------------------------------------------------!
74 SUBROUTINE calc_liquid_water_content
75 
76
77
78    USE arrays_3d,                                                             &
79        ONLY:  hyp, pt, q, qc, ql, qr
80
81    USE cloud_parameters,                                                      &
82        ONLY:  l_d_cp, l_d_r, t_d_pt
83
84    USE control_parameters,                                                    &
85        ONLY:  microphysics_seifert
86
87    USE indices,                                                               &
88        ONLY:  nxlg, nxrg, nyng, nysg, nzb, nzt, wall_flags_0
89
90    USE kinds
91
92    USE pegrid
93
94
95    IMPLICIT NONE
96
97    INTEGER(iwp) ::  i !<
98    INTEGER(iwp) ::  j !<
99    INTEGER(iwp) ::  k !<
100
101    REAL(wp) ::  alpha !<
102    REAL(wp) ::  e_s   !<
103    REAL(wp) ::  q_s   !<
104    REAL(wp) ::  t_l   !<
105
106    DO  i = nxlg, nxrg
107       DO  j = nysg, nyng
108          DO  k = nzb+1, nzt
109
110!
111!--          Compute the liquid water temperature
112             t_l = t_d_pt(k) * pt(k,j,i)
113
114!
115!--          Compute saturation water vapor pressure at t_l
116             e_s = 610.78_wp * EXP( 17.269_wp * ( t_l - 273.16_wp ) /          &
117                                                ( t_l - 35.86_wp ) )
118
119!
120!--          Compute approximation of saturation humidity
121             q_s = 0.622_wp * e_s / ( hyp(k) - 0.378_wp * e_s )
122
123!
124!--          Correction factor
125             alpha = 0.622_wp * l_d_r * l_d_cp / ( t_l * t_l )
126
127!
128!--          Correction of the approximated value
129!--          (see: Cuijpers + Duynkerke, 1993, JAS, 23)
130             q_s = q_s * ( 1.0_wp + alpha * q(k,j,i) ) / ( 1.0_wp + alpha * q_s )
131
132!
133!--          Compute the liquid water content
134             IF ( microphysics_seifert )  THEN
135                IF ( ( q(k,j,i) - q_s - qr(k,j,i) ) > 0.0_wp ) THEN
136                   qc(k,j,i) = ( q(k,j,i) - q_s - qr(k,j,i) )                  &
137                                      * MERGE( 1.0_wp, 0.0_wp,                 &
138                                               BTEST( wall_flags_0(k,j,i), 0 ) )
139                   ql(k,j,i) = ( qc(k,j,i) + qr(k,j,i) )                       &
140                                      * MERGE( 1.0_wp, 0.0_wp,                 &
141                                               BTEST( wall_flags_0(k,j,i), 0 ) )
142                ELSE
143                   IF ( q(k,j,i) < qr(k,j,i) )  q(k,j,i) = qr(k,j,i)
144                   qc(k,j,i) = 0.0_wp 
145                   ql(k,j,i) = qr(k,j,i)                                       &
146                                      * MERGE( 1.0_wp, 0.0_wp,                 &
147                                               BTEST( wall_flags_0(k,j,i), 0 ) )
148                ENDIF
149             ELSE
150                IF ( ( q(k,j,i) - q_s ) > 0.0_wp ) THEN
151                   qc(k,j,i) = ( q(k,j,i) - q_s )                              &
152                                      * MERGE( 1.0_wp, 0.0_wp,                 &
153                                               BTEST( wall_flags_0(k,j,i), 0 ) )
154                   ql(k,j,i) = qc(k,j,i)                                       &
155                                      * MERGE( 1.0_wp, 0.0_wp,                 &
156                                               BTEST( wall_flags_0(k,j,i), 0 ) )
157                ELSE
158                   qc(k,j,i) = 0.0_wp
159                   ql(k,j,i) = 0.0_wp
160                ENDIF
161             ENDIF
162          ENDDO
163       ENDDO
164    ENDDO
165   
166 END SUBROUTINE calc_liquid_water_content
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