Seasonal distribution and variability of atmospheric freeze/thaw cycles in Norway over the last six decades (1950–2013)

This study focused on atmospheric freeze/thaw cycles in Norway and presents the results of processing daily thermal data from 20 Norwegian meteorological stations for the period 1950–2013. Its two major aims were: (i) to provide long‐term time series of atmospheric freeze/thaw cycle data for Norway, and (ii) to analyse their trends over the last six decades. The study highlights the spatial and temporal modalities of the distribution of freeze/thaw cycles in Norway. The differences in the seasonal distributions of cycles and their mean annual number are because of the geographical location of the stations (coastal or inland stations, lowland or mountainous stations) and result from the combined effects of oceanity, continentality, latitude and elevation. The annual average number of freeze/thaw cycles is similar in the north (90) and south of Norway (84) but shows notable differences between coastal stations (27) and inland and/or mountainous stations (114). Since the 1950s, prolonged periods of several years characterized by increasing numbers of cycles have given way to periods of decreasing freeze/thaw frequency. This cyclicity is linked with the Northern Atlantic Oscillation (NAO). Strong positive or negative phases of the NAO since the 1950s have induced marked increases (or decreases) in atmospheric freeze/thaw cycle frequency in Norway.     

Characteristics and Altitudinal Distribution of Periglacial Decay Phenomena in the Massif of Rondane,Central Norway

The Norwegian massif of Rondane is part of the Scandes Mountains and is subject to polar, oceanic and continental influences. Because of its climatic context and its quartzitic structure, the massif has one of the thickest functional periglacial belts in Europe (1200 m). This belt is not fixed considering its translation in altitude since the end of the Little Ice Age. This mobility is continuing and involves periglacial decay dynamics which are revealed by numerous and various periglacial forms in the field. Because of their frequency in the massif and also their sensitivity to climate fluctuations, earth patches and small non‐sorted circles have a diagnostic value for current periglacial climate fluctuations. The major aim of this study is to propose several indicators of this periglacial decay and to highlight its consequences on periglacial belt mobility because these landforms enable the delimitation of a critical belt of decay in the massif.     

Recent patterned grounds development on a glacier surface (Dovrefjell,central Norway): an ephemeral periglacial activity in a paraglacial context

Researches carried out on the main glacier of the Dovrefjell massif, Scandes Mountains, Norway (62° N; 9° E) point to recent periglacial features which are presently directly developed on the ice. This original location raises the problem of their morphodynamic significance and a hypothesis of ephemeral periglacial activity in a paraglacial context is proposed here.