Search Results (3)

The airborne AirSWOT instrument suite, consisting of an interferometric Ka-band synthetic aperture radar and color-infrared (CIR) camera, was deployed to northern North America in July and August 2017 as part of the NASA Arctic-Boreal Vulnerability Experiment (ABoVE). We present validated, open (i.e., vegetation-free) surface water masks produced from high-resolution (1 m), co-registered AirSWOT CIR imagery using a semi-automated, object-based water classification. The imagery and resulting high-resolution water masks are available as open-access datasets and support interpretation of AirSWOT radar and other coincident ABoVE image products, including LVIS, UAVSAR, AIRMOSS, AVIRIS-NG, and CFIS. These synergies offer promising potential for multi-sensor analysis of Arctic-Boreal surface water bodies. In total, 3167 km² of open surface water were mapped from 23,380 km² of flight lines spanning 23 degrees of latitude and broad environmental gradients. Detected water body sizes range from 0.00004 km² (40 m²) to 15 km². Power-law extrapolations are commonly used to estimate the abundance of small lakes from coarser resolution imagery, and our mapped water bodies followed power-law distributions, but only for water bodies greater than 0.34 (±0.13) km² in area. For water bodies exceeding this size threshold, the coefficients of power-law fits vary for different Arctic-Boreal physiographic terrains (wetland, prairie pothole, lowland river valley, thermokarst, and Canadian Shield). Thus, direct mapping using high-resolution imagery remains the most accurate way to estimate the abundance of small surface water bodies. We conclude that empirical scaling relationships, useful for estimating total trace gas exchange and aquatic habitats on Arctic-Boreal landscapes, are uniquely enabled by high-resolution AirSWOT-like mappings and automated detection methods such as those developed here. Full article

The rise and abandonment of Uranium City constitutes an environmental history yet to be fully evaluated by humanities scholars. 1982 marks the withdrawal of the Eldorado Corporation from the town and the shuttering of its uranium mines. The population declined to approximately 50 from its pre-1982 population of about 4000. This article is inspired by findings from the authors’ initial field visit. As Uranium City is accessible only by air or by winter roads across Lake Athabasca, the goal of the visit in May 2017 was to gather information and questions through photographic assessment and through communication and interviews with residents. This paper in part argues that the cyclonic development metaphor used to describe single-commodity communities naturalizes environmental damage and obscures a more complicated history involving human agency. Apart from the former mines that garner remedial funding and action, the town site of Uranium City is also of environmental concern. Its derelict suburbs and landfill, we also argue, could benefit from assessment, funding, and remediation. Canada’s 2015 Truth and Reconciliation Commission Report provides a way forward in healing this region, in part by listening to the voices of those most affected by environmental impacts caused not by a metaphorical cyclone but by other humans’ decisions. As descendants of European immigrants to Turtle Island (the Indigenous term referring to North America), the authors are also subjects of the very terms—cyclonic development, abandonment, remediation—used to describe the history of the land itself: in this case, a mining town in the far northern boreal forests and Precambrian Shield. Full article

In Canada, climate change and forest harvesting may both threaten the ecological integrity of boreal lakes. To disentangle the effects of natural variation in climate and lake environments from those of logging, we evaluated long-term variation (1991–2003) in zooplankton communities of six boreal lakes in Ontario. We monitored concomitantly changes in zooplankton abundance and composition in three undisturbed and three harvested lakes, five years prior and eight years after watershed clearcut logging. We tested the hypothesis that long-term natural variation in climate and lake environments will be more important drivers of zooplankton community changes than short-term impacts of logging. We used space/time interaction tests and asymmetric eigenvector maps to model zooplankton responses to environmental changes and logging. Year-to-year variation in zooplankton abundance and composition were almost an order of magnitude whereas among-lake variation was stable through time. Breakpoints in time series of zooplankton in each lake were not directly related to logging. Climatic and limnological features were the most important drivers of long-term variation in the zooplankton community, shading the effect of logging. These results highlight the need to better understand the pressures exerted by climate change on boreal lake ecosystems in the context of anthropogenic pressure, such as logging. Full article