source: palm/trunk/SOURCE/init_cloud_physics.f90 @ 1053

Last change on this file since 1053 was 1053, checked in by hoffmann, 11 years ago

two-moment cloud physics implemented

  • Property svn:keywords set to Id
File size: 3.9 KB
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1 SUBROUTINE init_cloud_physics
2
3!--------------------------------------------------------------------------------!
4! This file is part of PALM.
5!
6! PALM is free software: you can redistribute it and/or modify it under the terms
7! of the GNU General Public License as published by the Free Software Foundation,
8! either version 3 of the License, or (at your option) any later 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 1997-2012  Leibniz University Hannover
18!--------------------------------------------------------------------------------!
19!
20! Current revisions:
21! -----------------
22! calculation of the maximum timestep according to the terminal velocity of rain
23! drops in the two moment cloud scheme
24!
25! calculation of frequently used constants (pirho_l, dpirho_l, schmidt_p_1d3,
26! hyrho)
27!
28! Former revisions:
29! ------------------
30! $Id: init_cloud_physics.f90 1053 2012-11-13 17:11:03Z hoffmann $
31!
32! 1036 2012-10-22 13:43:42Z raasch
33! code put under GPL (PALM 3.9)
34!
35! 824 2012-02-17 09:09:57Z raasch
36! calculation of b_cond replaced by calculation of bfactor
37!
38! 221 2009-01-12 15:32:23Z raasch
39! Bugfix: abort in case that absolute temperature is below zero
40!
41! 95 2007-06-02 16:48:38Z raasch
42! hydro_press renamed hyp
43!
44! February 2007
45! RCS Log replace by Id keyword, revision history cleaned up
46!
47! Revision 1.5  2005/06/26 19:55:58  raasch
48! Initialization of cloud droplet constants, gas_constant renamed r_d,
49! latent_heat renamed l_v
50!
51! Revision 1.1  2000/04/13 14:37:22  schroeter
52! Initial revision
53!
54!
55! Description:
56! ------------
57! Initialization of parameters for handling cloud-physics
58!------------------------------------------------------------------------------!
59
60    USE arrays_3d
61    USE cloud_parameters
62    USE constants
63    USE control_parameters
64    USE grid_variables
65    USE indices
66
67    IMPLICIT NONE
68
69    INTEGER ::  k
70    REAL    ::  t_surface
71
72    ALLOCATE( hyp(nzb:nzt+1), pt_d_t(nzb:nzt+1), t_d_pt(nzb:nzt+1),  &
73              hyrho(nzb:nzt+1) )
74
75!
76!-- Calculate frequently used parameters
77    l_d_cp = l_v / cp
78    l_d_r  = l_v / r_d
79    l_d_rv = l_v / r_v
80
81    schmidt_p_1d3 = schmidt**( 1.0 / 3.0 )
82
83    pirho_l  = pi * rho_l / 6.0
84    dpirho_l = 1.0 / pirho_l 
85!
86!-- Calculate timestep according to precipitation
87    IF ( icloud_scheme == 0  .AND.  precipitation )  THEN
88       dt_precipitation = MINVAL( dzu(nzb+2:nzt) ) / w_precipitation
89    ENDIF
90!
91!-- Calculate factor used in equation for droplet growth by condensation
92    bfactor = 3.0 * vanthoff * mass_of_solute * molecular_weight_of_water &
93              / ( 4.0 * pi * rho_l * molecular_weight_of_solute )
94!
95!-- Calculate:
96!-- pt / t : ratio of potential and actual temperature (pt_d_t)
97!-- t / pt : ratio of actual and potential temperature (t_d_pt)
98!-- p_0(z) : vertical profile of the hydrostatic pressure (hyp)
99    t_surface = pt_surface * ( surface_pressure / 1000.0 )**0.286
100    DO  k = nzb, nzt+1
101!
102!--    Check temperature in case of too large domain height
103       IF ( ( t_surface - g/cp * zu(k) ) < 0.0 )  THEN
104          WRITE( message_string, * )  'absolute temperature < 0.0 at zu(', k, &
105                                      ') = ', zu(k)
106          CALL message( 'init_cloud_physics', 'PA0142', 1, 2, 0, 6, 0 )
107       ENDIF
108       hyp(k)    = surface_pressure * 100.0 * &
109                   ( (t_surface - g/cp * zu(k)) / t_surface )**(1.0/0.286)
110       pt_d_t(k) = ( 100000.0 / hyp(k) )**0.286
111       t_d_pt(k) = 1.0 / pt_d_t(k)
112       hyrho(k)  = hyp(k) / ( r_d * t_d_pt(k) * pt_init(k) )       
113    ENDDO
114
115!
116!-- Compute reference density
117    rho_surface = surface_pressure * 100.0 / ( r_d * t_surface )
118
119
120 END SUBROUTINE init_cloud_physics
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