Click in the column header to display the table according to that column.

• Grid type refers to the file suffix used at the end of filenames for the OpenIFS/IFS climatology files. It is also used as an argument to the 'gaussgr' command, see 4.5 OpenIFS: Grid tools.
• The 'cubic' grid rather than 'cubic octahedral' is not listed here as it's infrequently used, the suffix for these files is '_3'.
• T21 and T42 use the Eulerian dynamical core and a regular Gaussian grid.
• T_co denotes cubic octahedral grid, T_l denotes a linear grid, T_q denotes a quadratic grid.
• Other resolutions not listed here may be provided with the OpenIFS climatology files.

this table is taken from the draft OpenIFS 40r1 paper & supplemented with 43r3 info for the cubic grids.

% this should match the resolutions of the climate data provided by OpenIFS.
% see  bin/gaussgr for further definitions of the grids.

% for resolution information, look at prepIFS defaults in:
% ~rdx/prepIFS.defaults/current/40r1/setup_fc/resolution
% gives (ignoring some resolutions, only including those for which we have climate files):

Look in /home/rd/rdx/data/ifs/rtable* to confirm no. of long pts at lats closest to eq (see Paul's message below).

%  T21,  _full, Eulerian dyn., 1800sec, 32x64
%  T42,  _full, Eul          , 1800sec, 64x128
%  T63,  _2   , Semi Lagr.   , 3600   , 96x192
%  T95,  l_2  , SL           , 3600   , 96x192
%  T106, _2   , SL?          , 3600   , 160x320 (LSLAG not set by 106.setup.save?)
%  T159, l_2  , SL           , 3600   , 160x320
%  T213, _2   , SL           , 1200   , 320x640
%  T255, l_2  , SL           , 2700   , 256x512
%  T319, l_2  , SL           , 1200   , 320x640
%  T399, l_2  , SL           , 1200   , 400x800
%  T511, l_2  , SL           , 900    , 512x1024
%  T639, l_2  , SL           , 900    , 640x1280
%  T799, l_2  , SL           , 720    , 800x1600
%  T1023, l_2 , SL           , 600    , 1024x2048
%  T1279, l_2 , SL           , 600    , 1280x2560
%
% _full, etc refer to the suffix on the model climate files, where _full mean regular (quadratic) Gaussian grid
% _2 means reduced regular grid, l_2 means reduced linear grid.

FOr 43r3, also look in the prepIFS default directory.
However, there is a discrepancy between the namfpd@NLON values in those files and the
formula on the octahedral grid page: Nlat = 4 x i + 16  where i=1,.. N.
For an O1280 grid (Tco1279) -> Nlat = 4 x 1280 + 16 = 5136. This doesn't match namfpd@NLON = 5120.
I've used the 4i+16 formula in working out the NLONeq values above for Tco grids.

Checking with Paul Dando (the oracle of all things grids...)

The formula for the number of longitude lines at latitude=i = 4*i + 16 (starting with i=1 nearest the pole) is definitely correct.  So the latitude nearest the equator for the O1280 grid has 4*1280 + 16 = 5136 longitude points.

In fact, you can check this in the NAMGRI namelist (read from, e.g. /home/rd/rdx/data/ifs/rtable_41279).  Here you will see that line nearest the pole has 20 points and those nearest the equator have 5136 points

My conclusion is, therefore, that namfpd has the wrong number for the octahedral grids.

Of course, I don't know what namfpd@NLON refers to in fullpos.  It could be that this is the number of longituide points on the full Gaussian grid (which is always 4*N) ?

Or perhaps it's just not been updated and still refers to the old-style reduced grids which did have 5120 points at the latitudes nearest the equator.

I hope that helps.