Just as the oceans cover a large fraction of the Earth's surface, so too do the cold regions, and they are even more poorly monitored. In the past, the main reason for little data being collected here was simply that few people lived in these regions or travelled to them, data coming in the last 150 years mostly from the occasional expedition to Antarctica or from a special laboratory such as on Ben Nevis in Scotland. But modern automatic instrument systems do not require frequent attention and it is now possible to site them anywhere. The main difficulty now in cold regions is not the need for operators but the problems of the environment itself.

Observation problems at low temperatures

Low temperature in itself is not a major problem for instruments. Electronic and mechanical components can operate in temperatures down to —40 °C or lower, and batteries continue to function at these extremes, although perhaps with a reduced capacity. The main problems arise from the effects of snow and ice adhering to (or filling) the sensors, often accompanied by strong winds. The question considered here is how to protect sensors from their damaging and disabling effects.