Another little nugget:

Dave Paige presented analysis of factors determining ice stability in
the near surface, specifically looking at the equatorial ice-rich
regions. He found that the zones of high H avoided smooth terrain, and
avoided high Thermal Inertia surfaces.

Both these factors destabilise shallow ice. On the other hand, low TI
encourages near surface ice and rugged terrain offers LOCAL
opportunities for ice to form in sheltered spots.

Given this, He suggested that the ~10% ice-equivalent H in the
equatorial regions was NOT a uniform 10%, but was instead patchy
distribution of, say, 20% of the surface with 50% ice.

In an extension of this, the gradient away from the poles could be the
introduction of increasing areas of ice-free ground in patches with
permafrost just as rich as in the circumpolar areas (although the
differential burial depth appears valid).