Lee Petersen on Nostr: The difference in melt is primarily due to the rock acting as an insulator to the ice ...

The difference in melt is primarily due to the rock acting as an insulator to the ice beneath, and the relationship is well understood. Debris-covered glaciers have much lower albedo than bare ice, therefore are actually absorbing more solar radiation that is re-radiated as IR. Thin layers of debris-cover (up to 2 cm) will actually melt ice faster than bare ice because the IR is absorbed more readily than UV from the Sun, despite the ice being in the "shade".