Recent ice conditions in North-Norwegian Porsangerfjorden

Abstract

Ice is a common occurrence in mainland Norwegian fjords in the vicinity of river mouths in winter. Fjord ice provides a wide array of services to society, including (1) acting as a coastal buffer (e.g. from pollution) and marine hazard; (2) providing a platform for recreational activities (e.g., travel and fishing); (3) serving as a full-scale model for Arctic sea ice (e.g., response training); and (4) participating in the fjord and coastal ecosystems. In spite of the local importance of ice in mainland Norwegian fjords, systematic investigations of its seasonal development and geophysical properties appear to be scarce. This study presents a summary of ice conditions in Porsangerfjorden from satellite observations of the past two decades (2000-2016) and discusses these in the context of local air temperature data and regional measurements of flow rates in rivers. Maximum ice extent was observed in March and a useful first approximation of ice extent in March could be derived from freezing degree days of February. However, local distribution of ice appears to be governed by factors beyond air temperature.