Morphodynamics of an abandoned delta lobe in NE Greenland

Typical wave-related morphologic features like spits are observed in the coastal area of an abandoned delta lobe in high-arctic Greenland. These wave-related features are created during the limited ice-free summer periods and slowly changes its morphology over time. The types of coastal processes are not different from those in temperate or tropical areas, but the intensity and duration of the processes differ. Here we describe the impact of wave- and tide-driven processes around the delta lobe to explain the morphologic changes. The spit as the most prominent feature evolves almost continuously under all moderate wave conditions from the SE and SSE (dominant wave direction in summer period) and extends in a western direction. At the same time, it can move onshore under high water level conditions (almost exclusively higher spring-tide highs). During these conditions, more exposed cliffs in former deltaic lobes are eroding under similar high water level events. This erosion is not constant in time and shows an alongshore spatial gradient. Cliff height decreases with distance away from the spit, and the more exposed and smaller cliffs in the east have the highest erosion rates. The presence of permafrost in the cliffs can locally reduce the erosion.