source: LMDZ6/branches/Optimisation_LMDZ/libf/phylmd/iniorbit.F90 @ 5017

Last change on this file since 5017 was 1992, checked in by lguez, 11 years ago

Converted to free source form files in libf/phylmd which were still in
fixed source form. The conversion was done using the polish mode of
the NAG Fortran Compiler.

In addition to converting to free source form, the processing of the
files also:

-- indented the code (including comments);

-- set Fortran keywords to uppercase, and set all other identifiers
to lower case;

-- added qualifiers to end statements (for example "end subroutine
conflx", instead of "end");

-- changed the terminating statements of all DO loops so that each
loop ends with an ENDDO statement (instead of a labeled continue).

-- replaced #include by include.

  • Property copyright set to
    Name of program: LMDZ
    Creation date: 1984
    Version: LMDZ5
    License: CeCILL version 2
    Holder: Laboratoire de m\'et\'eorologie dynamique, CNRS, UMR 8539
    See the license file in the root directory
File size: 2.6 KB
Line 
1SUBROUTINE iniorbit(paphelie, pperiheli, pyear_day, pperi_day, pobliq)
2  IMPLICIT NONE
3
4  ! =======================================================================
5
6  ! Auteur:
7  ! -------
8  ! Frederic Hourdin      22 Fevrier 1991
9
10  ! Objet:
11  ! ------
12  ! Initialisation du sous programme orbite qui calcule
13  ! a une date donnee de l'annee de duree year_day commencant
14  ! a l'equinoxe de printemps et dont le perihelie se situe
15  ! a la date peri_day, la distance au soleil et la declinaison.
16
17  ! Interface:
18  ! ----------
19  ! - Doit etre appele avant d'utiliser orbite.
20  ! - initialise une partie du common planete.h
21
22  ! Arguments:
23  ! ----------
24
25  ! Input:
26  ! ------
27  ! aphelie       \   aphelie et perihelie de l'orbite
28  ! periheli      /   en millions de kilometres.
29
30  ! =======================================================================
31
32  ! -----------------------------------------------------------------------
33  ! Declarations:
34  ! -------------
35
36  include "planete.h"
37  include "YOMCST.h"
38
39  ! Arguments:
40  ! ----------
41
42  REAL paphelie, pperiheli, pyear_day, pperi_day, pobliq
43
44  ! Local:
45  ! ------
46
47  REAL zxref, zanom, zz, zx0, zdx, pi
48  INTEGER iter
49
50  ! -----------------------------------------------------------------------
51
52  pi = 2.*asin(1.)
53
54  aphelie = paphelie
55  periheli = pperiheli
56  year_day = pyear_day
57  obliquit = pobliq
58  peri_day = pperi_day
59
60  PRINT *, 'Perihelie en Mkm  ', periheli
61  PRINT *, 'Aphelie  en Mkm   ', aphelie
62  PRINT *, 'obliquite en degres  :', obliquit
63  PRINT *, 'Jours dans l annee : ', year_day
64  PRINT *, 'Date perihelie : ', peri_day
65  unitastr = 149.597870
66  e_elips = (aphelie-periheli)/(periheli+aphelie)
67  p_elips = 0.5*(periheli+aphelie)*(1-e_elips*e_elips)/unitastr
68
69  PRINT *, 'e_elips', e_elips
70  PRINT *, 'p_elips', p_elips
71
72  ! -----------------------------------------------------------------------
73  ! calcul de l'angle polaire et de la distance au soleil :
74  ! -------------------------------------------------------
75
76  ! calcul de l'zanomalie moyenne
77
78  zz = (year_day-pperi_day)/year_day
79  zanom = 2.*pi*(zz-nint(zz))
80  zxref = abs(zanom)
81  PRINT *, 'zanom  ', zanom
82
83  ! resolution de l'equation horaire  zx0 - e * sin (zx0) = zxref
84  ! methode de Newton
85
86  zx0 = zxref + r_ecc*sin(zxref)
87  DO iter = 1, 100
88    zdx = -(zx0-r_ecc*sin(zx0)-zxref)/(1.-r_ecc*cos(zx0))
89    IF (abs(zdx)<=(1.E-12)) GO TO 120
90    zx0 = zx0 + zdx
91  END DO
92120 CONTINUE
93  zx0 = zx0 + zdx
94  IF (zanom<0.) zx0 = -zx0
95  PRINT *, 'zx0   ', zx0
96
97  ! zteta est la longitude solaire
98
99  timeperi = 2.*atan(sqrt((1.+r_ecc)/(1.-r_ecc))*tan(zx0/2.))
100  PRINT *, 'longitude solaire du perihelie timeperi = ', timeperi
101
102  RETURN
103END SUBROUTINE iniorbit
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