Can you clarify what you mean when you say "the pole_lat is not the north pole latitude at all"?
The rotation is counter-clockwise about the geographic North Pole.
To get a clearer understanding of the parameters pole_lat, pole_lon, and stand_lon, it may be helpful to try setting up a few global domains using the following geogrid settings.
Firstly, no rotation at all, with the geographic North Pole corresponding to the computational pole:
Code:
map_proj = 'lat-lon',
stand_lon = 0.0,
pole_lat = 90.0
pole_lon = 0.0
Secondly, shifting of the geographic North Pole to computational (lat,lon) = 45.0, 0.0:
Code:
map_proj = 'lat-lon',
stand_lon = 0.0,
pole_lat = 45.0
pole_lon = 0.0
Finally, rotation about the shifted North Pole by 60 degrees:
Code:
map_proj = 'lat-lon',
stand_lon = 60.0,
pole_lat = 45.0
pole_lon = 0.0