CPR Map of the North Pole of the Moon
This is a Mini-SAR map of the Circular Polarization Ratio (CPR) of the north pole of the Moon. Fresh, "normal" craters (red circles) show high values of CPR inside and outside their rims. This is consistent with the distribution of rocks and ejected blocks around fresh impact features, indicating that the high CPR here is surface scattering. The "anomalous" craters (green circles) have high CPR within, but not outside their rims. Their interiors are also in permanent sun shadow. These relations are consistent with the high CPR in this case being caused by water ice, which is only stable in the polar dark cold traps. We estimate over 600 million cubic meters (1 cubic meter = 1 metric ton) of water in these features.
Last Update: 22 May 2012 (AMB)