Possible grid configurations in GEM


GEM offers the possibilities of running global uniform, global stretched (or variable) and limited area (LAM) grids.
You will find explications about the grid specification parameters here (login and password are 'science').
Click here to find out how to set up a grid.

Global uniform grid:

Grd_typ_S = 'GU' ,




GU: Global Uniform
Grd_ni = 60 , Grd_nj = 30 ,
           total number of grid points in x- and y-direction

  

Global stretched (or variable) grid:

Grd_typ_S = 'GV' ,



         GV: Global Variable
Grd_ni = 63 , Grd_nj = 40 ,

total number of grid points in x- and y-direction        
Grd_nila = 20 , Grd_njla = 22 ,

number of grid points in high resolution area
Grd_dx = 2.5 , Grd_dy = 2.5 ,

grid size in degrees of high resolution area
Grd_dxmax = 7.5 , Grd_dymax = 7.5 ,

maximum grid size in degrees
Grd_xlon1 = -94.10 , Grd_xlat1 = 41.20 ,

Rotation:
location in "real" coordinates of the center (lat=0°, lon=180°) of the new grid on the real globe
Grd_xlon2 = -87.00 , Grd_xlat2 = 53.50 ,

location in "real" coordinates of any other point on the grid equator

  

Limited area grid (LAM):

Grd_typ_S = 'LU' ,



         LU: Lam Uniform
Grd_ni = 20
, Grd_nj = 22
,

total number of grid points in x- and y-direction        
Grd_dx = 2.50 , Grd_dy = 2.50 ,

grid size in degrees
Grd_xlon1 = -94.10 , Grd_xlat1 = 41.20 ,

Rotation:
location in "real" coordinates of the center (lat=0°, lon=180°) of the new grid on the real globe
Grd_xlon2 = -87.00 , Grd_xlat2 = 53.50 ,

location in "real" coordinates of any other point on the grid equator
Grd_iref = 10
, Grd_jref = 11
,

Location of limited area in (rotated) grid:
reference point in LAM grid
Grd_latr = 0.0 , Grd_lonr = 180.0 ,

location of reference point in "grid" coordinates

name list 'gement':
Pil_pil = 10
,
         Number of points for pilot area, default 7
Pil_hblen          =
10
,

Number of points for blending area, default 10

name list 'gem_cfgs':
Gbl_pil_[nsew] = 10
,
         Number of points for pilot area, default 7
Hblen_[xy]
=
10
,

Number of points for blending area, default 10


  




Author: Katja Winger
Last update: June 2008