Θw:
The most important features are the low troposphere and the instability in part of the area of the Polar Low. This deviates from the ideal case, where the polar low is expected to be fully within the unstable airmass.
PVA:
The vertical distribution of PVA shows several maxima in the neighbourhood of the Polar Low. However the maxima in the
lower layers does not fit to the ideal situation.
Vertical Motion (Omega):
The model fields are too coarse to find the right distibution of the upward and downward motions in a Polar Low. Maybe in
future non-hydrostatic mesoscale models will be the solution.
Potential Vorticity:
The vertical distribution of PV shows some lowering of the the PV=1 isohypse. However a real minimum is not seen due to the resolution of the model used.