Oras5 lat lon grid (that is nat_lan, nat_lon in *.nc files read in by xarray)

What is the oras5 lat lon grid like?

I read singles variable sst nc file like 

by  ds = xr.open_dataset('sosstsst_control_monthly_highres_2D_198008_CONS_v0.1.nc', engine="netcdf4")

and it seems that lat lon grid is not 0.25deg x 0.25 deg as one undertands from https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-oras5?tab=overview

min lat is about -77deg and max lat about +90deg,
in lat there are 1021 values, in lon 1442 values

Longitudes make sense, if you coarsen in xarray by 4 one gets 360 values as expected, but in latitudes one get 255 values.

Whats going on here? Is there somewhere description of lat lon system in ORAS5 dataset?

Or is this some map projection and not lat, lon???

I would like to get grid of one degree in lat and lon, it should not be that hard??? 

Cheers, Markus 


I got to transform the coordinates in 'normal' lat/lon using CDO.

cdo remapbil

I hope that helps :)

I'm new to this and i'm having the same problem with Ferret. Does anyone know what to do?
I'm trying to use the set region comand, but don´t know what to do with the lat values.

I would really appreciate your help

Cheers, Valentina