This:

h(t)=h(o)=exp(-RRPgt/2Dn)

This equation has cropped up to describe the rebound of land after an Ice sheet has been removed.

h(t) is the height after a time, t, has elapsed.

h(o) is the initial height

R is the radius of the depression/icesheet.

P is the density of the asthenosphere/rock.

g is the acceleration of gravity at earth's surface.

n is viscosity.

I don't know what D is though, and when I am rearranging to solve for viscosity this means I have a term of D left over in my answer.

I tried rearranging for its units and I get Metres Seconds; what does this represent?

edit: I think my previous assertion was spurious and that the units should be metres, so it must represent a depth. If anyone could explain this to me, that'd be good though.