Melt ponds in the context of Solar radiation

Meltwater (or melt water) is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves over oceans. Meltwater is often found during early spring when snow packs and frozen rivers melt with rising temperatures, and in the ablation zone of glaciers where the rate of snow cover is reducing. Meltwater can be produced during volcanic eruptions, in a similar way in which the more dangerous lahars form. It can also be produced by the heat generated by the flow itself.

When meltwater pools on the surface rather than flowing, it forms melt ponds. As the weather gets colder, meltwater will often re-freeze. Meltwater can also collect or melt under the ice's surface. These pools of water, known as subglacial lakes, can form due to geothermal heat and friction. Melt ponds may also form above and below Arctic sea ice, decreasing its albedo and causing the formation of thin underwater ice layers or false bottoms.

Antarctic sea ice is the sea ice of the Southern Ocean. It extends from the far north in the winter and retreats to almost the coastline every summer. Sea ice is frozen seawater that is usually less than a few meters thick. This is the opposite of ice shelves, which are formed by glaciers; they float in the sea, and are up to a kilometre thick. There are two subdivisions of sea ice: fast ice, which are attached to land; and ice floes, which are not.

Sea ice that comes from the Southern Ocean melts from the bottom instead of the surface like Arctic ice because it is covered in snow on top. As a result, melt ponds are rarely observed. On average, Antarctic sea ice is younger, thinner, warmer, saltier, and more mobile than Arctic sea ice. Another difference between the two ice packs is that while there is clear Arctic sea ice decline, the trend in Antarctica is roughly flat. Antarctic sea ice is not studied very well in comparison to Arctic ice since it is less accessible.