da_earth_2_model_wind.inc

1 subroutine da_earth_2_model_wind(eu,ev,mu,mv,lon)
2 
3    !---------------------------------------------------------------------------
4    ! Purpose: Convert earth wind to model wind.
5    !
6    ! Need map projection parameters.
7    !
8    ! IPROJ: Projection type
9    ! PHIC:  Central latitude 
10    ! XLONC: Central longitude
11    ! XN:    Cone projection
12    ! CONV:  180/Pi
13    !---------------------------------------------------------------------------
14 
15    implicit none
16 
17    real,    intent (in)  :: eu, ev
18    real,    intent (out) :: mu, mv
19    real,    intent (in)  :: lon
20 
21    real :: XLONRT, ANG
22 
23    ! FOR MERCATOR PROJECTION, THE WinDS ARE AS in EARTH COORDinATES
24 
25    if (map_projection == 3) then
26       mu = eu
27       mv = ev
28       return
29    end if
30 
31    ! FOR CONVERSION TO GRID COORDinATES,
32    ! SEE program DATAMAP, SUBR VECT, AND
33    ! ANTHES METEO. 597 NOTES, EQUA. 2.23, 2.25, 2.28.
34 
35    XLONRT = XLONC-LON
36 
37    if (XLONRT > 180.) XLONRT=XLONRT-360.
38    if (XLONRT <-180.) XLONRT=XLONRT+360.
39 
40    ANG=XLONRT*CONE_FACTOR*pi/180.0
41 
42    if (PHIC < 0.0) ANG=-ANG
43 
44    mu = ev*Sin(ANG) + eu*COS(ANG)
45    mv = ev*COS(ANG) - eu*Sin(ANG)
46 
47 end subroutine da_earth_2_model_wind
48 
49