Arctic Coastal Erosion: Modeling and Experimentation

Bull, Diana L; Bristol, E. M.; Brown, Eloise J.; Choens, Robert Charles; Connolly, Craig T.; Flanary, Christopher; Frederick, Jennifer M; Jones, Benjamin M.; Jones, Craig; Jones, Melissa K. Ward; McClelland, James M.; Mota, Alejandro; Tezaur, Irina Kalashnikova

doi:10.2172/1670531

Cited by 9 publications

(4 citation statements)

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“…Ice‐saturated permafrost loss has implications for coastal ecosystems and communities. For example, permafrost thaw decreases the strength of the sediment (Bull et al., 2020; Jorgenson et al., 2006). Thus extensive lateral thaw can enhance erosion rates and decrease coastal land stability with implications for the resilience of coastal communities and infrastructure they rely upon (Hjort et al., 2018).…”

Section: Discussionmentioning

confidence: 99%

Saltwater Intrusion Intensifies Coastal Permafrost Thaw

Guimond

Mohammed

Walvoord

et al. 2021

Geophysical Research Letters

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The Arctic is experiencing accelerated warming, with projected air temperature anomalies up to 8.3°C by 2100 (Collins et al., 2013;Landrum & Holland, 2020), causing widespread permafrost thaw (Turetsky et al., 2020). In the Arctic, permafrost, or ground less than 0°C for two or more consecutive years (Dobiński, 2013), mediates groundwater flow, storage, and exchange with surface water and acts as an aquitard where continuous (Walvoord & Kurylyk, 2016). With permafrost degradation, including top-down thaw and thermokarst processes, groundwater flow systems become increasingly active (Bense et al., 2009;Frampton & Destouni, 2015;Ge et al., 2011), as flowpaths lengthen and deepen (Walvoord & Kurylyk, 2016) and as relative permeability increases by up to seven orders of magnitude (Watanabe & Osada, 2016). While atmospheric warming threatens all permafrost (Jorgenson et al., 2006;Vaughan et al., 2013), coastal permafrost may be at a particularly high risk of thaw due to the combined effects of sea-level rise (SLR), land and ocean warming, and coastal erosion (Fritz et al., 2017).SLR drives surface and subsurface saltwater intrusion (SWI) into freshwater systems (Werner et al., 2013) by pushing the freshwater-saltwater interface (i.e., extent of saltwater wedge) landward (Figure 1). Along Arctic coastlines, previous geophysical studies suggest that the subsurface saltwater wedge creates unfrozen conditions (Kasprzak, 2020;Keating et al., 2018). However, understanding of the effects of subsurface SWI on ice-saturated permafrost (i.e., permafrost with high ice saturation) extent is limited, particularly over decadal to centennial timescales relevant to anthropogenic impacts. When pore ice-saturation is less

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Section: Discussionmentioning

confidence: 99%

Saltwater Intrusion Intensifies Coastal Permafrost Thaw

Guimond

Mohammed

Walvoord

et al. 2021

Geophysical Research Letters

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“…However, it appears that dissolved salts in the pore space of the sediments at Drew Point play an important role in lowering the permafrost freezing point and resulting in higher IBPT degradation rates than at Bykovsky. In fact, the top of onshore cryotic and saline unfrozen sediment layers (cryopegs) were observed near the Drew Point shoreline during coring (Bull et al, 2020;Bristol et al, 2021). This can lead us to interpret a faster IBPT degradation rate at Drew Point compared to Bykovsky in two ways: (1) a layer of submerged Drew Point sediments was already unfrozen upon inundation (e.g., M F2 in Fig.…”

Section: Subsea Permafrost Features (Bykovsky Vs Drewmentioning

confidence: 97%

Exploring the capabilities of electrical resistivity tomography to study subsea permafrost

et al. 2022

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Abstract. Sea level rise and coastal erosion have inundated large areas of Arctic permafrost. Submergence by warm and saline waters increases the rate of inundated permafrost thaw compared to sub-aerial thawing on land. Studying the contact between the unfrozen and frozen sediments below the seabed, also known as the ice-bearing permafrost table (IBPT), provides valuable information to understand the evolution of sub-aquatic permafrost, which is key to improving and understanding coastal erosion prediction models and potential greenhouse gas emissions. In this study, we use data from 2D electrical resistivity tomography (ERT) collected in the nearshore coastal zone of two Arctic regions that differ in their environmental conditions (e.g., seawater depth and resistivity) to image and study the subsea permafrost. The inversion of 2D ERT data sets is commonly performed using deterministic approaches that favor smoothed solutions, which are typically interpreted using a user-specified resistivity threshold to identify the IBPT position. In contrast, to target the IBPT position directly during inversion, we use a layer-based model parameterization and a global optimization approach to invert our ERT data. This approach results in ensembles of layered 2D model solutions, which we use to identify the IBPT and estimate the resistivity of the unfrozen and frozen sediments, including estimates of uncertainties. Additionally, we globally invert 1D synthetic resistivity data and perform sensitivity analyses to study, in a simpler way, the correlations and influences of our model parameters. The set of methods provided in this study may help to further exploit ERT data collected in such permafrost environments as well as for the design of future field experiments.

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“…These range from detailed process representation (e.g. Kobayashi et al 1999;Hoque and Pollard 2009;Ravens et al 2012;Barnhart et al 2014a;Bull et al 2020) to empirical approaches scalable to more extensive segments of coast (e.g. Kupilik et al 2019Kupilik et al , 2020Nielsen et al 2022) and initial consideration of artificial intelligence strategies (Irrgang et al 2022).…”

Section: Previous Workmentioning

confidence: 99%

Mechanisms, volumetric assessment, and prognosis for rapid coastal erosion of Tuktoyaktuk Island, an important natural barrier for the harbour and community

et al. 2022

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The coastline of the Inuvialuit Settlement Region (ISR) in the Mackenzie –Beaufort region of the western Canadian Arctic is characterized by rapid erosion of ice-bonded sediments with abundant excess ground ice, resulting in widespread thermal and mechanical process interactions in the shore zone. Coastal communities within the ISR are acutely aware of the rapidly eroding coastline and its impacts on infrastructure, subsistence activities, cultural or ancestral sites, and natural habitats. Tuktoyaktuk Island is a large natural barrier protecting the harbour and surrounding community from exposure to waves. It is threatened by coastal erosion, a better understanding of which will inform adaptation strategies. Using historical and recent aerial imagery, high-resolution digital elevation models, cliff geomorphology, stratigraphy, and sedimentology, including ground-ice content, this study documents erosional processes, recession rates, volume losses and sediment delivery since 1947, and projected into the future. Erosion along the northwest-facing (exposed) cliff, primarily by thermo-abrasional undercutting and block failure, has accelerated since 2000 to a mean of 1.8 ± 0.02 m/yr, a 22% increase over the previous 15 years and 17% faster than 1947-2000. Lower recession rates on the harbour side of the island increased more than two-fold. Projection of future shoreline vectors by extrapolation, using the post-2000 accelerated coastal recession rates at 284 transects, points to breaching of this vital natural harbour barrier by 2044, after which rapid realignment is expected to occur as the new inlet evolves. Further acceleration of rates, as seems highly likely, brings the breaching date closer.

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Arctic Coastal Erosion: Modeling and Experimentation

Cited by 9 publications

References 0 publications

Saltwater Intrusion Intensifies Coastal Permafrost Thaw

Saltwater Intrusion Intensifies Coastal Permafrost Thaw

Exploring the capabilities of electrical resistivity tomography to study subsea permafrost

Mechanisms, volumetric assessment, and prognosis for rapid coastal erosion of Tuktoyaktuk Island, an important natural barrier for the harbour and community

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