LATTICE – Land-terminating ice cliffs in North Greenland

Glaciers that end as steep ice cliffs on land are unusual phenomena of the cryosphere. These cliffs only occur in places where cold and dry climatic conditions dominate. In North Greenland, the edge of the ice sheet and adjacent ice caps form numerous ice cliffs, but only the Red Rock ice cliff has been extensively explored in the past. Over the last six decades, the ice of this cliff has been thinning, but at the same time there have been phases of advance, retreat and re-advance. This seemingly contradictory behaviour of advancing and thinning at the same time has remained unexplored in detail and raises the question of the driving processes. We argue that the changes in the Red Rock ice cliff reflect the climate variability. Therefore, we hypothesise that any change in the ice cliff is a climate indicator of the relationship between the atmosphere and the cryosphere in North Greenland. If we understand the interaction of the ice cliff with the atmosphere, we can translate changes in the ice cliff into a climate signal. This signal is of regional importance for a large part of the cold and dry north of Greenland. We are investigating the processes that determine the changes in the ice cliff, its morphology, position and thickness. Using on-site measurements and numerical models, we are able to determine the role of ice dynamics, quantify ice break-up and melting on the cliff, and investigate the sensitivity of the energy and mass balance to climate. Using ice flow models driven with measured historical and current ice temperatures, we investigate whether possible warming of the ice could have influenced the observed advance of the cliff. Energy and mass balance models provide information on the sensitivity of the ice cliff to further changes in climate. We expect the sensitivity to air temperature to be lower than to climate elements related to moisture, such as humidity, cloud cover and precipitation. In this way, we are contributing to research into a wetter and warmer Arctic in future. Linking the small-scale influencing factors with the variability of the regional climate will significantly expand our knowledge of the interrelationships between the atmosphere, cryosphere and ocean in North Greenland, a region that is crucial for the global climate.