EP23A-0941
Shoreline changes and its impact on activities in the coastal zone in Greenland
Abstract:
Arctic coastal processes are not only affected by waves, tides and currents, but to a large extend by freezing temperatures, ice and snow. There is a seasonal variation with open waters and active rivers in summer and ice-covered coastal waters and frozen rivers in winter. The coastal processes by waves and tides are thus often limited to summer and early fall. Nowadays, global climate changes induce many changes along the arctic coasts. Global sea-levels are rising due to thermal expansion and an increased fresh water flux from the glaciers and land ice masses, while ice coverage of the coastal waters decreases and the open water periods in summer extend. However, it is still unknown if the extra input of fluvial sediments can cope with increased erosion rates at the shores. Besides, the rate of actual sea-level rise in West Greenland is probably less than the local rate of isostatic uplift, leading to local relative sea level fall.
The focus in this presentation is on shoreline changes and its impact on two coastal environments in Greenland: the Young Sound area (fjord environment in North-East Greenland), and the southern shore of Disko Island (open sea embayment in West Greenland). These coastal environments exhibit a wide variety of coastal landforms like deltas, spits, barriers, etc. The coastal landforms were mapped and aerial images, orthogonal photos, and satellite images were used to digitize successive shorelines. The shoreline changes were estimated using the digital shoreline analysis system (DSAS) of the USGS. The spatial variability of accumulation and erosion patterns was detected and shows a surprising thread for ancient settlements and present-day activities in the coastal zone. The same patterns are finally discussed in terms of coastal risk assessment.