Arctic nearshore current dynamics and wave climate under declining sea ice conditions Potential impacts on sediment pathways A case study from Herschel Island – Qikiqtaruk, Yukon Coast, Canada

• Main Author: Gimsa, Justus
• Format: Thesis
• Language: unknown
• Published: 2019
• Subjects: Arctic; Arctic Ocean; Beaufort Sea; Herschel; Herschel Island; Sea ice; Yukon
• Online Access: https://epic.awi.de/id/eprint/52100/; https://epic.awi.de/id/eprint/52100/1/Master_Thesis_Justus_Gimsa.pdf; https://hdl.handle.net/10013/epic.a702d509-5e0d-4cee-8125-832e07061416

The coast of the Western Canadian Arctic is facing rapid changes under ongoing Arctic warming. As coastal erosion rates are accelerating, detailed insights into the interplay of erosional forcing parameter like wind, waves, the influence of river discharge and currents are needed. The first ever measurements of currents in the nearshore zone of the Western Canadian Beaufort Sea, reveal a substantial effect on winds on the generation of currents. In coupling the data of two current measurements in the summer season, we found that time-lag and potential direction dependence complicate the response. Sea ice played a large role in the reduction of wave activity and largely supressed water movement in the surface layer. In general, a decreased in current speed from surface to bottom was visible at both mooring locations. While at the first location current geometries throughout the water column equal and are directed offshore, at the other site current direction were opposed. The recorded current speed at both sites agree with previous values in the Canadian Beaufort Sea. Yet, with ongoing changes in the environmental forcing of the Arctic Ocean the currents in the study area are likely to change as well. These new insights can help to comprehend the annual cycle of water movement, with insights for the transport of eroded sediment in summer, the redistribution of sediment in fall storms and the spread of Mackenzie plume water in the breakup season. This knowledge may help to improve the protection of threatened historic coastal settlements and understand the further shoreline change development along the Yukon Coast.