The annual cycle for whimbrel populations using the Western Atlantic Flyway

Many long-distance migratory birds use habitats that are scattered across continents and confront hazards throughout the annual cycle that may be population-limiting. Identifying where and when populations spend their time is fundamental to effective management. We tracked 34 adult whimbrels (Numenius phaeopus) from two breeding populations (Mackenzie Delta and Hudson Bay) with satellite transmitters to document the structure of their annual cycles. The two populations differed in their use of migratory pathways and their seasonal schedules. Mackenzie Delta whimbrels made long (22,800 km) loop migrations with different autumn and spring routes. Hudson Bay whimbrels made shorter (17,500 km) and more direct migrations along the same route during autumn and spring. The two populations overlap on the winter grounds and within one spring staging area. Mackenzie Delta whimbrels left the breeding ground, arrived on winter grounds, left winter grounds and arrived on spring staging areas earlier compared to whimbrels from Hudson Bay. For both populations, migration speed was significantly higher during spring compared to autumn migration. Faster migration was achieved by having fewer and shorter stopovers en route. We identified five migratory staging areas including four that were used during autumn and two that were used during spring. Whimbrels tracked for multiple years had high (98%) fidelity to staging areas. We documented dozens of locations where birds stopped for short periods along nearly all migration routes. The consistent use of very few staging areas suggests that these areas are integral to the annual cycle of both populations and have high conservation value.

Geomorphological patterns of remotely sensed methane hot spots in the Mackenzie Delta, Canada

We studied geomorphological controls on methane (CH4) hotspots in the Mackenzie Delta region in northern Canada using airborne imaging spectroscopy collected as part of the Arctic Boreal Vulnerability Experiment (ABoVE). Methane emissions hotspots were retrieved at ~25 m2 spatial resolution from a ~10,000 km2 AVIRIS-NG survey of the Mackenzie Delta acquired 31 July – 3 August 2017. Separating the region into the permafrost plateau and the lowland delta, we refined the domain wide power law of CH4 enhancements detected as a function of distance to standing water in different ecoregions. We further studied the spatial decay of the distance to water relationship as a function of land cover across the Delta. We show that geomorphology exerts a strong control on the spatial patterns of emissions at regional to sub-regional scales: compared to methane hotspots detected in the upland, we find that methane hotspots detected in the lowland have a more gradual power law curve indicating a weaker spatial decay with respect to distance from water. Spatial decay of CH4 hotspots in uplands is more than 2.5 times stronger than in lowlands, which is due to differences in topography and geomorphological influence on hydrology. We demonstrate that while the observed spatial distributions of CH4 follow expected trends in lowlands and uplands, these quantitatively complement knowledge from conventional wetland and freshwater CH4 mapping and modelling.

Assessment of Storm Surge History as Recorded by Driftwood in the Mackenzie Delta and Tuktoyaktuk Coastlands, Arctic Canada

The southern Beaufort coastline in Canada experiences significant storm surge events that are thought to play an important role in coastal erosion and influence permafrost dynamics. Unfortunately, many of these events have not been documented with tide gauge records. In this paper, we evaluate coastal driftwood accumulations as a proxy for estimating maximum storm surge heights and the history of these events. We use historical air photos and data derived from Unoccupied Aerial Vehicle (UAV) imagery to resurvey four coastal stranded driftwood study sites that were first appraised in 1985–86 and assess two new regional sites in the Mackenzie Delta. Maximum storm surge heights were found to be similar to observations carried out in the 1980s, however, we refine the elevations with more accuracy and reference these to a vertical datum appropriate for incorporating into sea level hazard assessments. Detailed mapping, historical air photo comparisons and the UAV acquired imagery at a site close to Tuktoyaktuk demonstrate that the highest storm surge at this site (1.98 m CGVD2013) occurred in association with a severe storm in 1970. This event shifted driftwood and floated material slightly upslope from an older event thought to occur in 1944 that reached 1.85 m (CGVD2013) elevation. The quality and accuracy of the high-resolution Digital Surface Model (DSM) and orthophoto derived from Structure from Motion (SfM) processing of the UAV photographs allowed mapping of four distinct stratigraphic units within the driftwood piles. Based on variations in anthropogenic debris composition, weathering characteristics and history of movement on aerial photographs, we conclude that no storm surge events at Tuktoyaktuk have exceeded ∼1.3 m (CGVD2013) since 1970. While there has been some speculation that ongoing climate change may lead to more frequent large magnitude storm surges along the Beaufort coast, our study and available tide gauge measurements, suggest that while moderate elevation storm surges may be more frequent in the past several decades, they have not approached the magnitude of the 1970 event.

The Tempo of Solid Fluids: On River Ice, Permafrost, and Other Melting Matter in the Mackenzie Delta

Seasonal and historical transformations of ice and permafrost suggest that the Mackenzie Delta in Arctic Canada can be understood as a solid fluid. The concerns and practices of delta inhabitants show that fluidity and solidity remain important attributes in a solid fluid delta. They are significant not as exclusive properties, but as relational qualities, in the context of particular human projects and activities. Indigenous philosophies of ‘the land’ and Henri Lefebvre’s notion of ‘tempo’ in Rhythmanalysis: Space, Time and Everyday Life (2004) may help to illustrate the predicament of living in a world that is solid and fluid rhythmically, and in relation to particular practices. Economic, political, sociocultural and physical transformations can all be experienced as both solid and fluid, depending on the degree to which they resonate with people’s purposes. In a world where everything seems to be changed and changing, solidity and fluidity may best be seen as indications of relative differences in tempo.

Thermal Design of Pipelines – A Challenge for Flow Assurance in the Arctic

Increasing demand for energy is driving the need to explore the deeper oceans and the far north. While higher temperature, pressure and longer tie-backs are challenges going deep, highly sensitive environment is an issue exploring far north. The discovery of large reserves in the far north has brought the challenges of exploration, production, and transportation in the cold regions like Prudhoe Bay, the Mackenzie Delta, and the Arctic Islands into focus. To transport hydrocarbons to market, pipelines used in the Arctic have unique challenges and stringent design conditions that must be met to ensure reliable operations in such remote and sensitive environments. To avoid flow assurance risks, the adage “the hotter the better” is in stark contrast to the sensitive nature of the Arctic environment to temperature changes, and where “the colder the better” is more appropriate. Permafrost, and its potential disturbance, is the most important factor to be considered for pipeline thermal design. High temperatures can disturb the in-situ state of the permafrost, causing settlement and instability in the permafrost zone. Also, high pipeline temperatures demand deep trenches to avoid melting the surface ice, challenging installation and increasing CAPEX. Designing the pipeline to maintain high internal fluid temperatures to reduce flow assurance risks and lower pipeline outer temperatures to minimize the impact on the environment is the best solution. To maintain high fluid temperatures and reduce heat loss to the environment, the conventional idea of a high value insulation like pipe-in-pipe with a vacuum annulus to avoid heat loss to the sensitive Arctic surroundings may seem to be a good solution, but it may not be the optimal solution. This paper discusses a hypothetical scenario (based on field cases) of a multiphase pipeline design and highlights the associated flow assurance/operational risks.

Whimbrel populations differ in trans-atlantic pathways and cyclone encounters

Each year hundreds of millions of birds cross the Atlantic Ocean during the peak of tropical cyclone activity. The extent and consequences of migrant-storm interactions remain unknown. We tracked whimbrels from two populations (Mackenzie Delta; Hudson Bay) to examine overlap between migration routes and storm activity and both the frequency and consequence of storm encounters. Here we show that Mackenzie Delta and Hudson Bay whimbrels follow different routes across the ocean and experience dramatically different rates of storm encounters. Mackenzie Delta whimbrels departed North America from Atlantic Canada, made long ($$\bar{x}$$ x ¯ = 5440 ± 120.3 km) nonstop flights far out to sea that took several days ($$\bar{x}$$ x ¯ = 6.1 ± 0.18) to complete and encountered storms during 3 of 22 crossings. Hudson Bay whimbrels departed North America from the south Atlantic Coast, made shorter ($$\bar{x}$$ x ¯ = 3643 ± 196.2 km) nonstop flights across the Caribbean Basin that took less time ($$\bar{x}$$ x ¯ = 4.5 ± 0.29) to complete and encountered storms during 13 of 18 crossings. More than half of Hudson Bay storm encounters resulted in groundings on Caribbean islands. Grounded birds required longer ($$\bar{x}$$ x ¯ = 30.4 ± 5.32 days) to complete trans-Atlantic crossings and three were lost including 2 to hunters and 1 to a predator. One of the Mackenzie Delta whimbrels was lost at sea while crossing the Intertropical Convergence Zone. Whimbrels use two contrasting strategies to cross the Atlantic including (1) a long nonstop flight around the core of storm activity with a low likelihood of encountering storms but no safety net and (2) a shorter flight through the heart of Hurricane Alley with a high likelihood of encountering storms and a safety network of islands to use in the event of an encounter. Demographic consequences of storm encounters will likely play a role in the ongoing evolution of trans-Atlantic migration pathways as global temperatures continue to rise.

3D SAR Speckle Offset Tracking Potential for Monitoring Landfast Ice Growth and Displacement

This study investigates the growth and displacement of landfast ice along the shoreline of the Mackenzie Delta in Northwest Territories, Canada, by synthetic aperture radar (SAR) speckle offset tracking (SPO). Three-dimensional (3D) offsets were reconstructed from Sentinel-1 ascending and descending SAR images acquired on the same dates during the November 2017–April 2018 and October 2018–May 2019 annual cycles. The analysis revealed both horizontal and vertical offsets. The annual horizontal offsets of up to ~8 m are interpreted as landfast ice displacements caused by wind and ocean currents. The annual vertical offsets of approximately −1 to −2 m were observed from landfast ice, which are likely due to longer radar penetration up to the ice–water interface with increasing landfast ice thickness. Numerical ice thickness model estimates supported the conclusion that the cumulative vertical negative offsets correspond to the growth of freshwater ice. Time-series analysis showed that the significant growth and displacement of landfast ice in the Mackenzie Delta occurred between November and January during the 2017–2018 and 2018–2019 cycles.

Shoreline changes at the regional scale in Tuktoyaktuk and the Mackenzie Delta, calculated using Landsat satellite imagery from 1985 to 2013

The Canadian Arctic has long been perceived by many as a vast area of barren and frozen land, sparsely populated, and of little importance to the country’s economic growth. However, today this is no longer the case. The changing environment and increased development in this region have led to numerous environmental ramifications, one of the most prominent being shoreline changes. The purpose of this study is to investigate the impacts climate change, natural mechanisms, and increased anthropogenic activity have had on the shoreline in the hamlet of Tuktoyaktuk in the Northwest Territories, and the surrounding Mackenzie Delta from 1985 to 2013 using Landsat satellite imagery. Shoreline changes are quantified and given a rate and directional vector over time in order to determine the predominant trends of erosion or deposition. The results of this investigation indicate that shoreline erosion is one of the leading mechanisms of shoreline change in this region.

Shoreline changes at the regional scale in Tuktoyaktuk and the Mackenzie Delta, calculated using Landsat satellite imagery from 1985 to 2013

The Canadian Arctic has long been perceived by many as a vast area of barren and frozen land, sparsely populated, and of little importance to the country’s economic growth. However, today this is no longer the case. The changing environment and increased development in this region have led to numerous environmental ramifications, one of the most prominent being shoreline changes. The purpose of this study is to investigate the impacts climate change, natural mechanisms, and increased anthropogenic activity have had on the shoreline in the hamlet of Tuktoyaktuk in the Northwest Territories, and the surrounding Mackenzie Delta from 1985 to 2013 using Landsat satellite imagery. Shoreline changes are quantified and given a rate and directional vector over time in order to determine the predominant trends of erosion or deposition. The results of this investigation indicate that shoreline erosion is one of the leading mechanisms of shoreline change in this region.