Author(s): Randi Pytte Asvall; Anund Sigurd Kvambekk
Linked Author(s):
Keywords: River ice; Lake ice; Climatic change
Abstract: Information on ice cover has been collected in Norway for a long time. Through the ages it has been a great interest in knowledge on the bearing capacity of ice for winter roads. Today the ice is less important for heavy transport, but still important for more light weight traffic and recreation. The importance of an ice cover for certain biological conditions has gradually been recognized. The length of the ice season is particularly sensitive to length of time with freezing temperatures and amount of snow fall. In the scenarioes of global warming for Norway the effect appears to be different for different parts of the country. There is expected more unstable ice conditions along the coast and maritime areas from the south and as far north as to the arctic circle. The effect on ice will be somewhat different on rivers than on lakes. The information on amount and quality of ice varies with time and area. The most extensive information we have is from the older manual water gage observations, before the introduction of automatic recording instruments. Then the ice situation was observed every day, and we have many quite long series. These are mainly river stations. For later years water temperature measurements can supplement the river ice information. On selected lakes the ice conditions and/or duration of the ice cover have been observed for many years. Ice conditions for any year are a result of the weather that corresponding winter, and not of the climate throughout previous year, as the case is for the biological life in a water course. Based on this we have selected years similar to typical years in the global warming scenario for different parts of the country, and from there indicated a possible scenario for future ice conditions.
Year: 2006