Geology, Especially Geomorphology, of Northern Alaska

Black, Robert F.

doi:10.14430/arctic3220

Cited by 9 publications

(4 citation statements)

References 59 publications

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“…Some areas located close to coastlines are known to have an abundance of shallow lakes. This abundance, as found on the North Slope and on parts of the Lena Delta, point to comparably young lakes of Pleistocene age (Black, 1969;Schwamborn et al, 2002).…”

Section: Regional Patternssupporting

confidence: 65%

Circumpolar Mapping of Ground-Fast Lake Ice

et al. 2017

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Shallow lakes are common across the entire Arctic. They play an important role as methane sources and wildlife habitats, and they are also associated with thermokarst processes which are characteristic of permafrost environments. Many lakes freeze to the ground along their rims and often over the entire extent during winter time. Knowledge on the spatial patterns of ground-fast and floating ice is important as it relates to methane release, talik formation and hydrological processes, but no circumpolar account of this phenomenon is currently available. Previous studies have shown that ground-fast ice can easily be detected using C-band Synthetic Aperture Radar (SAR) backscatter intensity data acquired from satellites. A major challenge is that backscatter intensity varies across the satellite scenes due to incidence angle effects. Circumpolar application therefore requires the inclusion of incidence angle dependencies into the detection algorithm. An approach using ENVISAT ASAR Wide Swath data (approximately 120 m spatial resolution) has therefore been developed supported by bathymetric measurements for lakes in Siberia. This approach was then further applied across the entire Arctic for late winter 2008. Ground-fast ice fraction has been derived for (1) two million lake objects larger than 0.025 km 2 (post-processed GlobeLand30), (2) a 50 × 50 km grid and (3) within certain zones relevant for climate studies (permafrost type, last glacial maximum, Yedoma). Especially lakes smaller than approximately 0.1 km 2 may freeze completely to the ground. The proportion of ground-fast ice increases with increasing soil organic carbon content in the proximity of the lakes. This underlines the importance of such lakes for emission studies and the need to map the occurrence of ground-fast lake ice. Clusters of variable fractions of ground-fast ice occur especially in Yedoma regions of Eastern Siberia and Alaska. This reflects the nature of thaw lake dynamics. Analyses of lake depth measurements from several sites suggest that the used method yields the potential to utilize ground-fast lake ice information over larger areas with respect to landscape development, but results need to be treated with care, specifically for larger lakes and along river courses.

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Section: Regional Patternssupporting

confidence: 65%

Circumpolar Mapping of Ground-Fast Lake Ice

et al. 2017

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“…Thaw lakes have long been considered a unique feature of the Alaskan Arctic Coastal Plain. The origin, geometry, growth, age, and the impact of thaw lakes have captured the interest of many investigators [ Black and Barksdale , 1949; Hopkins , 1949; Brewer , 1958a, 1958b; Carson and Hussey , 1962; Brown , 1965; Carson , 1968; Black , 1969; Sellmann et al , 1975a, 1975b; Mellor , 1982; Jeffries et al , 1996; Kozlenko and Jeffries , 2000]. Lake ice growth, decay, and sensitivity to climate change have also been studied by some researchers by using energy balance models [ Heron and Woo , 1994; Liston and Hall , 1995a, 1995b] and numerical heat transfer models with phase change [ Bilello , 1980; Ashton , 1983; Jeffries et al , 1999; Zhang and Jefffies , 2000].…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of permafrost thermal regime and talik development under shallow thaw lakes on the Alaskan Arctic Coastal Plain

2003

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[1] Thaw lakes are one of the most obvious manifestations of the hydrological system at work in the tundra regions of the Alaskan Arctic Coastal Plain, but the extent of the role of thaw lakes in Arctic land-atmosphere interactions and feedback has yet to be fully understood. This study uses a two-dimensional heat transfer model with phase change under a cylindrical coordinate system to simulate the long-term influence of shallow thaw lakes on the thermal regime of permafrost and talik development on the Alaskan Arctic Coastal Plain. On the basis of previous studies of permafrost and thaw lakes at Barrow, Alaska, a series of simulation cases was conducted using different combinations of long-term mean lake bottom temperature and lake depth. The simulated results indicate that shallow thaw lakes are a significant heat source to permafrost and talik. For a thaw lake with a long-term mean lake bottom temperature of greater than 0.0°C a talik forms under the thaw lake. The maximum talik thicknesses (vertical distance from the ground surface to the permafrost surface) are 28.0, 43.0, and 53.2 m 3000 years after the formation of a shallow thaw lake with long-term mean lake bottom temperatures of 1.0°, 2.0°, and 3.0°C, respectively. Talik development rate is very high in the first several years after a thaw lake formation and decreases gradually with time. No talik forms below a thaw lake with a long-term mean lake bottom temperature equal to or lower than 0.0°C, but the temperature of permafrost below the thaw lake increases with time. Three thousand years after the formation of a thaw lake with a long-term mean lake bottom temperature of greater than or equal to À2.0°C, ground temperature increases of more than 0.5°C occur as far as 300 m from the lake shore and as deep as about 400 m below the ground surface. It is concluded that variation of long-term mean lake bottom temperature has a significant influence on permafrost thermal regime and talik development. Continued monitoring for thaw lake bottom temperature and ground temperature under shallow thaw lakes is needed to further improve the simulation.

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“…Moist acidic tundra covers the study area in the Imnavait and Upper Kuparuk basins in the Toolik Lake LTER area. The erosional topography on the landscape is created by Cretaceous sedimentary rocks forming east‐west trending open folds [ Black , ]. Elevation in the region varies from 844 to 960 m. Glaciation in the middle Pleistocene during the Sagavanirktok advance created the incised rolling hills and covered the area with glacial till [ Hamilton , ].…”

Section: Study Areamentioning

confidence: 99%

Remote sensing of water tracks

Trochim

Prakash

Kane

et al. 2016

Earth and Space Science

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Water tracks are an intrinsic part of the surficial drainage network in the foothills of the Brooks Range, Alaska. They preferentially transport water off hillslopes and represent the interplay between hydrology, vegetation, geomorphology, and permafrost characteristics. This research on mapping the location of water tracks builds on previous work which demonstrated that different types of water tracks exist due to difference primarily driven by geomorphology. We used a combination method where spectral classifications, texture, and topography were fed into random forests to identify the water track classes. The most accurate distributions were obtained for the organic-rich and wide water track classes. The distinct linear shapes of the water tracks could also be visualized for many of the classes, especially in areas where the water tracks were particularly discrete. The biggest challenges to mapping the water tracks were due to class imbalances and high variability within and overlapping between classes. This research presents a significant step forward in understanding periglacial landscape dynamics.

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Geology, Especially Geomorphology, of Northern Alaska

Cited by 9 publications

References 59 publications

Circumpolar Mapping of Ground-Fast Lake Ice

Circumpolar Mapping of Ground-Fast Lake Ice

Numerical simulation of permafrost thermal regime and talik development under shallow thaw lakes on the Alaskan Arctic Coastal Plain

Remote sensing of water tracks

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