Mass Balance of Martian Ice Caps: Is There Another Type of Polar Glacier?

The recent discovery of water ice exposed to the atmosphere in the polar regions of Mars raises some interesting questions. It implies that at least some water vapor is being lost to the atmosphere by these exposed ice surfaces. If one assumes steady state, the question immediately arises as to how this ice is being replaced. It is proposed that a new type of polar glacier is possible in very cold regions with large annual temperature cycles and with relatively low annual ablation. It is also suggested that terrestrial analogues exist, but they have never been described because they are relatively unspectacular and exist in remote regions seldom visited by glaciologists.