Consensus-Based Rock Glacier Inventorying in the Torngat Mountains, Northern Labrador

Way, Robert G.; Wang, Yifeng; Bevington, Alexandre; Bonnaventure, Philip P.; Burton, Jake R.; Davis, Emma; Garibaldi, Madeleine C.; Lapalme, Caitlin; Tutton, Rosamond; Wehbe, M.

doi:10.1061/9780784483589.012

Cited by 3 publications

(1 citation statement)

References 34 publications

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“…In the validation part, we estimated the thickness-related error by considering the uncertainty involved in delineating the rock glacier area based on Google Earth images. The uncertainties were caused by multiple factors such as the variable image quality, the subjective judgement of operators, and the complexity of the rock glacier morphology (Brardinoni et al, 2019;Schmid et al, 2015;Way et al, 2021). We assumed a 40 % uncertainty in the area parameter, leading to a ∼ 10 % error (or an absolute error of 2-4 m) in thickness.…”

Section: Derivation Of Rock Glacier Thicknessmentioning

confidence: 99%

Modelling rock glacier ice content based on InSAR-derived velocity, Khumbu and Lhotse valleys, Nepal

Hu¹,

Harrison²,

Liu³

2023

The Cryosphere

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Abstract. Active rock glaciers are viscous flow features embodying ice-rich permafrost and other ice masses. They contain significant amounts of ground ice and serve as potential freshwater reservoirs as mountain glaciers melt in response to climate warming. However, current knowledge about ice content in rock glaciers has been acquired mainly from in situ investigations in limited study areas, which hinders a comprehensive understanding of ice storage in rock glaciers situated in remote mountains over local to regional scales. This study proposes a novel approach for assessing the hydrological value of rock glaciers in a more quantitative way and presents exploratory results focusing on a small region. We develop an empirical rheological model to infer ice content of rock glaciers using readily available input data, including rock glacier planar shape, surface slope angle, active layer thickness, and surface velocity. The model is calibrated and validated using observational data from the Chilean Andes and the Swiss Alps. We apply the model to five rock glaciers in the Khumbu and Lhotse valleys, northeastern Nepal. The velocity constraints applied to the model are derived from interferometric synthetic aperture radar (InSAR) measurements. The volume of rock glacier is estimated based on an existing scaling approach. The inferred volumetric ice fraction in the Khumbu and Lhotse valleys ranges from 70 ± 8 % to 74 ± 8 %, and the water volume equivalents lie between 1.4 ± 0.2 and 5.9±0.6×106 m3 for the coherently moving parts of individual rock glaciers. Due to the accessibility of the model inputs, our approach is applicable to permafrost regions where observational data are lacking, which is valuable for estimating the water storage potential of rock glaciers in remote areas.

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Section: Derivation Of Rock Glacier Thicknessmentioning

confidence: 99%

Modelling rock glacier ice content based on InSAR-derived velocity, Khumbu and Lhotse valleys, Nepal

Hu¹,

Harrison²,

Liu³

2023

The Cryosphere

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Significant underestimation of peatland permafrost along the Labrador Sea coastline in northern Canada

Wang¹,

Way²,

Beer³

et al. 2023

The Cryosphere

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Abstract. Northern peatlands cover approximately four million km2, and about half of these peatlands are estimated to contain permafrost and periglacial landforms, like palsas and peat plateaus. In northeastern Canada, peatland permafrost is predicted to be concentrated in the western interior of Labrador but is assumed to be largely absent along the Labrador Sea coastline. However, the paucity of observations of peatland permafrost in the interior, coupled with traditional and ongoing use of perennially frozen peatlands along the coast by Labrador Inuit and Innu, suggests a need for re-evaluation of the reliability of existing peatland permafrost distribution estimates for the region. In this study, we develop a multi-stage consensus-based point inventory of peatland permafrost complexes in coastal Labrador and adjacent parts of Quebec using high-resolution satellite imagery, and we validate it with extensive field visits and low-altitude aerial photography and videography. A subset of 2092 wetland complexes that potentially contained peatland permafrost were inventoried, of which 1119 were classified as likely containing peatland permafrost. Likely peatland permafrost complexes were mostly found in lowlands within 22 km of the coastline, where mean annual air temperatures often exceed +1 ∘C. A clear gradient in peatland permafrost distribution exists from the outer coasts, where peatland permafrost is more abundant, to inland peatlands, where permafrost is generally absent. This coastal gradient may be attributed to a combination of climatic and geomorphological influences which lead to lower insolation, thinner snowpacks, and poorly drained, frost-susceptible materials along the coast. The results of this study suggest that existing estimates of permafrost distribution for southeastern Labrador require adjustments to better reflect the abundance of peatland permafrost complexes to the south of the regional sporadic discontinuous permafrost limit. This study constitutes the first dedicated peatland permafrost inventory for Labrador and provides an important baseline for future mapping, modelling, and climate change adaptation strategy development in the region.

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Inventory of rock glaciers in the Torngat Mountains of northern Labrador

Way,

Wang

2022

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Consensus-Based Rock Glacier Inventorying in the Torngat Mountains, Northern Labrador

Cited by 3 publications

References 34 publications

Modelling rock glacier ice content based on InSAR-derived velocity, Khumbu and Lhotse valleys, Nepal

Modelling rock glacier ice content based on InSAR-derived velocity, Khumbu and Lhotse valleys, Nepal

Significant underestimation of peatland permafrost along the Labrador Sea coastline in northern Canada

Inventory of rock glaciers in the Torngat Mountains of northern Labrador

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