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Increased industrial development in the Arctic has led to a rapid expansion of infrastructure in the region. Localized impacts of infrastructure on snow distribution, road dust, and snowmelt timing and duration feeds back into the coupled Arctic system causing a series of cascading effects that remain poorly understood. We quantify spatial and temporal patterns of snow-off dates in the Prudhoe Bay Oilfield, Alaska, using Sentinel-2 data. We derive the Normalized Difference Snow Index to quantify snow persistence in 2019–2020. The Normalized Difference Vegetation Index and Normalized Difference Water Index were used to show linkages of vegetation and surface hydrology, in relationship to patterns of snowmelt. Newly available infrastructure data were used to analyze snowmelt patterns in relation infrastructure. Results show a relationship between snowmelt and distance to infrastructure varying by use and traffic load, and orientation relative to the prevailing wind direction (up to 1 month difference in snow-free dates). Post-snowmelt surface water area showed a strong negative correlation (up to −0.927) with distance to infrastructure. Results from field observations indicate an impact of infrastructure on winter near-surface ground temperature and snow depth. This study highlights the impact of infrastructure on a large area beyond the direct human footprint and the interconnectedness between snow-off timing, vegetation, surface hydrology, and near-surface ground temperatures.

 

This dataset supports the findings of the research paper submitted to the journal Geophysical Research Letters that documents the rapid thaw of saline permafrost below a shallow thermokarst lake near Utqiagvik, Alaska. The lake, East Twin Lake, is located in the Barrow Environmental Observatory. We conducted repeat drilling-based surveys at East Twin Lake in the Barrow Environmental Observatory near Utqiagvik, Alaska between 2008 and 2023. These field data were integrated with transient electromagnetic (TEM) near-surface geophysics soundings in 2016 and 2022 and analysis of a time-series of wintertime Synthetic Aperture Radar (SAR) satellite imagery from 2015 to 2023 to assess changes in lake and sub-lake properties. Finally, we assessed the impact of thawing saline permafrost on shore erosion by quantifying a regime shift in the lateral expansion rate of East Twin Lake between 1948 and 2022. The datasets consist of a CSV file with the point measurements from the drilling campaign, processed TEM data along with the script, a table of SAR backscatter values extracted for three lakes, and a table with lake expansion rates for East Twin Lake. 

Permafrost warming and degradation is well documented across the Arctic. However, observation‐ and model‐based studies typically consider thaw to occur at 0°C, neglecting the widespread occurrence of saline permafrost in coastal plain regions. In this study, we document rapid saline permafrost thaw below a shallow arctic lake. Over the 15‐year period, the lakebed subsided by 0.6 m as ice‐rich, saline permafrost thawed. Repeat transient electromagnetic measurements show that near‐surface bulk sediment electrical conductivity increased by 198% between 2016 and 2022. Analysis of wintertime Synthetic Aperture Radar satellite imagery indicates a transition from a bedfast to a floating ice lake with brackish water due to saline permafrost thaw. The regime shift likely contributed to the 65% increase in thermokarst lake lateral expansion rates. Our results indicate that thawing saline permafrost may be contributing to an increase in landscape change rates in the Arctic faster than anticipated.

 

The 2015 spring flood of the Sagavanirktok River inundated large swaths of tundra as well as infrastructure near Prudhoe Bay, Alaska. Its lasting impact on permafrost, vegetation, and hydrology is unknown but compels attention in light of changing Arctic flood regimes. We combined InSAR and optical satellite observations to quantify subdecadal permafrost terrain changes and identify their controls. While the flood locally induced quasi‐instantaneous ice‐wedge melt, much larger areas were characterized by subtle, spatially variable post‐flood changes. Surface deformation from 2015 to 2019 estimated from ALOS‐2 and Sentinel‐1 InSAR varied substantially within and across terrain units, with greater subsidence on average in flooded locations. Subsidence exceeding 5 cm was locally observed in inundated ice‐rich units and also in inactive floodplains. Overall, subsidence increased with deposit age and thus ground ice content, but many flooded ice‐rich units remained stable, indicating variable drivers of deformation. On average, subsiding ice‐rich locations showed increases in observed greenness and wetness. Conversely, many ice‐poor floodplains greened without deforming. Ice wedge degradation in flooded locations with elevated subsidence was mostly of limited intensity, and the observed subsidence largely stopped within 2 years. Based on remote sensing and limited field observations, we propose that the disparate subdecadal changes were influenced by spatially variable drivers (e.g., sediment deposition, organic layer), controls (ground ice and its degree of protection), and feedback processes. Remote sensing helps quantify the heterogeneous interactions between permafrost, vegetation, and hydrology across permafrost‐affected fluvial landscapes. Interdisciplinary monitoring is needed to improve predictions of landscape dynamics and to constrain sediment, nutrient, and carbon budgets.

 

Abstract. Thermokarst lake dynamics, which play an essential role in carbon releasedue to permafrost thaw, are affected by various geomorphological processes.In this study, we derive a three-dimensional (3D) Stefan equation tocharacterize talik geometry under a hypothetical thermokarst lake in thecontinuous permafrost region. Using the Euler equation in the calculus ofvariations, the lower bounds of the talik were determined as an extremum ofthe functional describing the phase boundary area with a fixed total talikvolume. We demonstrate that the semi-ellipsoid geometry of the talik isoptimal for minimizing the total permafrost thaw under the lake for a givenannual heat supply. The model predicting ellipsoidal talik geometry wascompared to talik thickness observations using transient electromagnetic(TEM) soundings in Peatball Lake on the Arctic Coastal Plain (ACP) ofnorthern Alaska. The depth : width ratio of the elliptical sub-lake talik cancharacterize the energy flux anisotropy in the permafrost, although the lakebathymetry cross section may not be elliptic due to the presence ofnear-surface ice-rich permafrost. This theory suggests that talikdevelopment deepens lakes and results in more uniform horizontal lakeexpansion around the perimeter of the lakes, while wind-induced waves andcurrents are likely responsible for the elongation and orientation ofshallow thermokarst lakes without taliks in certain regions such as the ACPof northern Alaska. 

Environmental impact assessments for new Arctic infrastructure do not adequately consider the likely long-term cumulative effects of climate change and infrastructure to landforms and vegetation in areas with ice-rich permafrost, due in part to lack of long-term environmental studies that monitor changes after the infrastructure is built. This case study examines long-term (1949–2020) climate- and road-related changes in a network of ice-wedge polygons, Prudhoe Bay Oilfield, Alaska. We studied four trajectories of change along a heavily traveled road and a relatively remote site. During 20 years prior to the oilfield development, the climate and landscapes changed very little. During 50 years after development, climate-related changes included increased numbers of thermokarst ponds, changes to ice-wedge-polygon morphology, snow distribution, thaw depths, dominant vegetation types, and shrub abundance. Road dust strongly affected plant-community structure and composition, particularly small forbs, mosses, and lichens. Flooding increased permafrost degradation, polygon center-trough elevation contrasts, and vegetation productivity. It was not possible to isolate infrastructure impacts from climate impacts, but the combined datasets provide unique insights into the rate and extent of ecological disturbances associated with infrastructure-affected landscapes under decades of climate warming. We conclude with recommendations for future cumulative impact assessments in areas with ice-rich permafrost. 

We studied processes of ice-wedge degradation and stabilization at three sites adjacent to road infrastructure in the Prudhoe Bay Oilfield, Alaska, USA. We examined climatic, environmental, and subsurface conditions and evaluated vulnerability of ice wedges to thermokarst in undisturbed and road-affected areas. Vulnerability of ice wedges strongly depends on the structure and thickness of soil layers above ice wedges, including the active, transient, and intermediate layers. In comparison with the undisturbed area, sites adjacent to the roads had smaller average thicknesses of the protective intermediate layer (4 cm vs. 9 cm), and this layer was absent above almost 60% of ice wedges (vs. ∼45% in undisturbed areas). Despite the strong influence of infrastructure, ice-wedge degradation is a reversible process. Deepening of troughs during ice-wedge degradation leads to a substantial increase in mean annual ground temperatures but not in thaw depths. Thus, stabilization of ice wedges in the areas of cold continuous permafrost can occur despite accumulation of snow and water in the troughs. Although thermokarst is usually more severe in flooded areas, higher plant productivity, more litter, and mineral material (including road dust) accumulating in the troughs contribute to formation of the intermediate layer, which protects ice wedges from further melting. 

This data set covers the younger outer coastal plain north of Teshekpuk Lake, North Slope, Alaska. In this region, drained lake basins are abundant features, covering large parts of the landscape. This data set is based on Landsat Thematic Mapper (TM) imagery acquired in August 2010, and a 5 meter (m) resolution Interferometric Synthetic Aperture Radar (IfSAR)-derived digital terrain model. Drained lake basins were manually delineated in a geographic information system (GIS). The data set includes Lake 195, which drained in this area in 2014. For further details please see Jones et al. (2015): Jones, BM, and Arp, CD (2015), Observing a Catastrophic Thermokarst Lake Drainage in Northern Alaska. Permafrost and Periglac. Process., 26, 119– 128. doi: 10.1002/ppp.1842. 

This data set covers the younger outer coastal plain north of Teshekpuk Lake, North Slope, Alaska. In this region, drained lake basins are abundant features, covering large parts of the landscape. This data set is based on Landsat Thematic Mapper (TM) imagery acquired in August 2010, and a 5 meter (m) resolution Interferometric Synthetic Aperture Radar (IfSAR)-derived digital terrain model. Drained lake basins were manually delineated in a geographic information system (GIS). The data set includes Lake 195, which drained in this area in 2014. For further details please see Jones et al. (2015): Jones, BM, and Arp, CD (2015), Observing a Catastrophic Thermokarst Lake Drainage in Northern Alaska. Permafrost and Periglac. Process., 26, 119– 128. doi: 10.1002/ppp.1842. 

Lakes are abundant features on coastal plains of the Arctic, providing important fish and wildlife habitat and water supply for villages and industry, but also interact with frozen ground (permafrost) and the carbon it stores. Most of these lakes are termed "thermokarst" because they form in ice-rich permafrost and gradually expand over time. The dynamic nature of thermokarst lakes also makes them prone to catastrophic drainage and abrupt conversion to wetlands, called drained thermokarst lake basins (DTLBs). Together, thermokarst lakes and DTLBs cover up to 80% of arctic lowland regions, making understanding their response to ongoing climate change essential for coastal plain environmental assessment. Dating the timing of lake drainage can improve our understanding of the causes and consequences of DTLB formation. This suite of 14C (Carbon-14) ages provides insight into the timing of lake drainage on the North Slope of Alaska across a range of ecosystems and surficial geology types.