GRIB2 - GRID DEFINITION TEMPLATE 3.13

Mercator with modelling subdomains definition

Created 05/30/2019


Octet No. Contents
15
Shape of the Earth (See Code Table 3.2)
16
Scale factor of radius of spherical Earth
17-20
Scale value of radius of spherical Earth
21
Scale factor of major axis of oblate spheroid Earth
22-25
Scaled value of major axis of oblate spheroid Earth
26
Scale factor of minor axis of oblate spheroid Earth
27-30 Scaled value of minor axis of oblate spheroid Earth
31-34

Nj—number of points along a parallel  

35-38

Nj—number of points along a meridian

39-42
La1 ― latitude of first grid point
43-46
Lo1 ― longitude of first grid point
47
Resolution and component flags (see Flag Table 3.3)
48-51

LaD — latitude(s) at which the Mercator projection intersects the Earth (Latitude(s) where Di and Dj are specified)  

52-55
La2 ― latitude of last grid point
56-59

Lo2 — longitude of last grid point   

60 Scanning mode (flags — see Flag Table 3.4)
61-64

Orientation of the grid, angle between i direction on the map and the Equator  (see Note1)     

65-68

Dj —  longitudinal direction grid length (see Note 2)

69-72

Dj ― latitudinal direction grid length  (see Note 2)

72-76 Nux – size of model forecast subdomain in x-direction (number of grid points)
77-80 Ncx – width of coupling area within forecast domain in x-direction (number of grid points)
81-84 Nuy – size of model forecast subdomain in y-direction (number of grid points)
85-88 Ncy – width of coupling area within forecast domain in y-direction (number of grid points)


Notes:

1.  Limited to the range of  0 to 90 degrees; if the angle of orientation of the grid is neither 0 nor 90 degrees, Di and Dj must be equal to each other.

2.  Grid lengths are in units of 10-3  m, at the latitude specified by LaD.

3.  A scale value of radius of spherical Earth, or major or minor axis of oblate spheroid Earth is derived from applying appropriate scale factor to the value expressed in metres.


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