Remote sensing analysis of recent coastal change and its controlling factors in Darnley Bay (Amundsen Gulf, Canada)

• Autor(a) principal: Tanguy, Rodrigue Raymond Phoebus
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/19453
• topic: Coastal dynamics; Permafrost; Darnley Bay; Paulatuk; Remote sensing.; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

As the Arctic warms, permafrost coasts are experiencing higher rates of erosion, threatening coastal communities and infrastructure, and altering sediment and nutrient budgets. However, some areas are still neglected by research. The mouth of the Gulf of Amundsen is home to Darnley Bay, while the coast of the ecologically important Cape Parry to Paulatuk area included in the Anguniaqvia Niqiqyuam Marine Protected Area has been still little studied. This area is home to Arctic char, cod, beluga whales, ringed and bearded seals, polar bears and sea birds. It is also an important area for the Inuvialuit who have an intrinsic attachment to their land ensuring the survival of their culture and food source. Settled in Paulatuk, Inuvialuit are witnessing the warming of their territory and the degradation of the permafrost. This study aims to establish the geomorphological characterization of the Paulatuk coast and peninsula and to quantify coastal changes over 55 years, using a new very high resolution survey based on CNES Pleiades imagery from August 2020, as well as historical aerial imagery from 1965. Key areas, such as Paulatuk, were also surveyed using unmanned aerial vehicles in 2019. The results indicate a small average erosion rate of -0.1 m/year of the surveyed coastlines from 1965 to 2020. At a regional scale, there is a disparity in erosion rates depending on the type of substrate. Erosion rates are significantly different in function of the type of coastal material. Unconsolidated areas show erosion rates of up to -3 m/year while consolidated express stability. These values are relatively low compared to other sites on the Beaufort Sea Coast (e.g. Qikiqtaryuk/Herschel Island, Yukon coast, Mackenzie delta), which are more susceptible to erosion due to soil composition, ground ice content, cliff height and exposure to swells. The very high resolution geomorphological mapping provide important spatial information to the coastal community. Paulatuk is showing signs of degrading permafrost landscape with subsidence zones and potential thaw ponds drainage. A preliminary assessment suggest that infrastructure construction influences permafrost degradation and that future soil thawing process could become a threat for the community. This study, based on unprecedented very high resolution data contributes to the general characterization and identification of erosion rates of the Arctic coasts.