Long-Term High Resolution Sediment and Sea Surface Temperature Spatial Patterns in Arctic Nearshore Waters retrieved using 30-year Landsat Archive Imagery

• Main Authors: Klein, Konstantin, Lantuit, Hugues, Heim, Birgit, Irrgang, Anna, Fell, Frank, Doxaran, David, Sachs, Torsten
• Format: Conference Object
• Language: unknown
• Published: 2019
• Subjects: Arctic; Mackenzie River; Herschel Island; Beaufort Shelf; Climate change; Mackenzie river; permafrost
• Online Access: https://epic.awi.de/id/eprint/49672/; https://epic.awi.de/id/eprint/49672/1/Poster_LPS_1.pdf; https://hdl.handle.net/

The Arctic is directly impacted by climate change. The increase in air temperature drives the thawing of permafrost and an increase in coastal erosion and river discharge. This leads to a greater input of sediment and organic matter into coastal waters, which substantially impacts ecosystems and the subsistence economy of the local population. Yet, the patterns of sediment dispersal in nearshore zones are not well known, because ships do not often reach shallow waters and satellite remote sensing is traditionally focused on less dynamic environments. We use the extensive Landsat archive to investigate sediment dispersal patterns specifically on Arctic nearshore environments, where field measurements are scarce. Multiple Landsat scenes were combined to calculate means and medians of sediment dispersal and sea surface temperatures under changing seasonal wind conditions in the nearshore zone of Herschel Island Qikiqtaruk in the western Canadian Arctic since 1982. We use the Landsat red and thermal wavebands, as well as a recently published water turbidity algorithm to relate archive wind data to suspended sediment concentrations and sea surface temperature. We also map the transport pathways of water and sediment along the coast at high spatial resolution. Our results show that these pathways are clearly related to the prevailing wind conditions, being ESE and NW. During easterly wind conditions, the Mackenzie River plume expands over extensive parts of the western Canadian Beaufort Shelf and is the main explanatory variable for sediment dispersal and sea surface temperature distributions. During northwesterly wind conditions, the influence of the Mackenzie River Plume is negligible and regional currents along the coast are the main driver. Our results highlight potential of high spatial resolution Landsat imagery to detect small scale hydrodynamic features, but also show the need to specifically tune a bio-optical model for Arctic nearshore environments.