2016-17 - Kokelj et al - Distribution and activity of ice wedges across the forest-tundra transition, western Arctic Canada - CIMP164

File Identifier: {BF4EA1B5-355A-4175-9720-C4E8F6B70264}

Metadata Language: en

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Organisation Name: CIMP

Role: Point Of Contact

Contact Info:

E-Mail Address: donnamarie_ouellette@gov.nt.ca

Metadata Date: 2017-07-07

Metadata Standard Name: ISO 19139/19115 Metadata for Datasets

Metadata Standard Version: 2003

Abstract: Remote sensing, regional ground temperature and ground ice observations, and numerical simulation were used to investigate the size, distribution, and activity of ice wedges in fine-grained mineral and organic soils across the forest-tundra transition in uplands east of theMackenzie Delta. In the northernmost dwarf-shrub tundra, ice wedge polygons cover up to 40% of the ground surface, with the wedges commonly exceeding 3m in width. The largest ice wedges are in peatlands where thermal contraction cracking occurs more frequently than in nearby hummocky terrain with fine-grained soils. There are fewer ice wedges, rarely exceeding 2m in width, in uplands to the south and none have been found in mineral soils of the tall-shrub tundra, although active icewedges are found there throughout peatlands. In the spruce forest zone, small, relict ice wedges are restricted to peatlands. At tundra sites, winter temperatures at the top of permafrost are lower in organic than mineral soils because of the shallow permafrost table, occurrence of phase change at 0°C, and the relatively high thermal conductivity of icy peat. Due to these factors and the high coefficient of thermal contraction of frozen saturated peat, ice wedge cracking and growth is more common in peatlands than in mineral soil. However, the high latent heat content of saturated organic active layer soils may inhibit freezeback, particularly where thick snow accumulates,making the permafrost and the ice wedges in spruce forest polygonal peatlands susceptible to degradation following alteration of drainage or climate warming.

Language: en

Citation:

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Title: 2016-17 - Kokelj et al - Distribution and activity of ice wedges across the forest-tundra transition, western Arctic Canada - CIMP164

Date:

Date: 2017-07-07

Date Type: Publication Date

Point Of Contact:

Individual Name: Steve Kokelj

Organisation Name: NTGO

Role: Point Of Contact

Topic Category: Environment and Conservation

Keyword Collection:

Keyword: Ice wedges

Keyword: forest

Keyword: tundra

Keyword: western arctic canada

Keyword: CIMP164

Spatial Extent:

West Bounding Longitude: -136.247

East Bounding Longitude: -130.2302

North Bounding Latitude: 70.4793

South Bounding Latitude: 68.2247

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URL: https://nwtdiscoveryportal.enr.gov.nt.ca/geoportaldocuments/2016-17%20-%20REPORT%20-%20Kokelj_et_al%20-%20Distribution%20and%20activity%20of%20ice%20wedges%20across%20the%20forest-tundra%20transition.pdf

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Organisation Name: Cumulative Impact Monitoring Program (CIMP)

Role: Point Of Contact