The development of an automatic weather station for cold regions

The Institute of Hydrology developed its first automatic weather station (AWS) in the 1960's using conventional sensors. In 1976 a project was started to develop an AWS able to operate in cold regions where severe icing normally prevents the collection of data. These developments are now well advanced. The AWS measure solar radiation, albedo, temperature, humidity, wind speed, wind direction and precipitation. Using a test site in the Scottish Highlands, techniques were developed, based on pneumatic shock-induction, flexing and the use of hydrophobic materials, to keep the station ice-free, without the use of power. New sensors and new ways of deploying sensors were developed to suit these techniques and their perfomance compared with that of conventional sensors. The ice prevention techniques, the new sensors, their performance and the path of future developments, are described.