Modelled Distribution and Temporal Evolution of Permafrost in Steep Rock Walls Along a Latitudinal Transect in Norway by CryoGrid 2D

Abstract

Steep permafrost rock walls marking the transition from high-lying plains to low-altitude fjord and valley systems are common in Norway. We have investigated the climate sensitivity of rock wall permafrost along a latitudinal transect from southern to northern Norway (60°N to 70°N) using topographic profiles from both natural sites and idealised sites with simplified geometries with steep rock walls bordering a flat plateau. We applied a two-dimensional ((2)D) transient thermal model (CryoGrid 2D) that includes both space- and time-dependent thermal parameters and the latent heat of ice-water phase transitions. The model has been forced using temperature data interpolated from meteorological observations between the end of the Little Ice Age and present warmer climatic conditions. We varied our model runs by changing the assumption of snow covers and applying glaciers at the plateaus. Our results show that the existence, geometry and thermal regime of the permafrost varies strongly depending on the snow and glacier cover on the plateau. Snow-free rock walls substantially govern the heat flow out of the rock wall, cooling the mountain interior below the plateau and favouring the development of permafrost beneath the margins of some plateaus. Copyright © 2015 John Wiley & Sons, Ltd.