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Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions C-Change in.

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1 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions C-Change in GEES Changing Permafrost Environments Session Two Session Two: Permafrost Definitions

2 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions How to use the teaching slides  These slides are not intended to form a complete lecture on the session topic.  These resources are designed to suggest a framework to help tutors develop their own lecture material  The resource slides comprise where appropriate; key points, case studies, images, references and further resources.  There are limited case studies included. Students can develop their own portfolio of case studies as part of coursework activities  These resources may be used for educational purposes only, for other uses please contact the author  These slides were last updated in February 2010

3 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Disclaimer  Links within this presentation may lead to other sites. These are provided for convenience only. We do not sponsor, endorse or otherwise approve of any information or statements appearing in those sites. The author is not responsible for the availability of, or the content located on or through, any such external site.  While every effort and care has been taken in preparing the content of this presentation, the author disclaims all warranties, expressed or implied, as to the accuracy of the information in any of the content. The author also (to the extent permitted by law) shall not be liable for any losses or damages arising from the use of, or reliance on, the information. The author is also not liable for any losses or damages arising from the use of, or reliance on sites linked to this site, or the internet generally.  Pictures, photographs and diagrams within this presentation have been produced by the author unless otherwise stipulated  No content within this resource is knowingly an infringement of copyright. Any infringement can be immediately rectified on notification of the author of the resource

4 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Lecture Topics Terminology employed in the study of permafrost. Definition of permafrost zones. Relationship between climate and permafrost. Additional factors that affect the distribution and thickness permafrost. Dryas, Arctic Coastal Plain (R I Waller)

5 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Some Common Terms Talik: layer or lens of unfrozen ground; can occur on top of, within or below the permafrost. Active layer: Surface layer that seasonally freezes and thaws. (geomorphologically important) Permafrost Table: Upper boundary of the permafrost layer. Cryotic: Below 0°C. Refers to temperature rather than state (thawed/frozen). (Different as freezing point often depressed below 0°C)

6 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Schematic Cross Section through Permafrost After: French, H.M. 2007. The Periglacial Environment (3 rd ed.). Wiley & Sons, Chichester. P.84

7 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Surface Geotherms in the Mountains of SW Alberta Note how the surface layer oscillates seasonally above and below 0°C (seasonally cryotic layer). Figure From: Harris, S.A. 1986. The Permafrost Environment. Croom Helm, Beckenham (p.25). © Croom Helm Publishers

8 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Permafrost Environments Permafrost is frequently subdivided into three geographical zones according to its spatial extent: –Continuous: permafrost is ubiquitous except for localised taliks below large lakes and rivers –Discontinuous: Bodies of frozen ground separated by sizeable areas of unfrozen ground –Sporadic: permafrost restricted to isolated islands, often located beneath peaty sediments Additional environments include: –Alpine permafrost. –Subsea permafrost –Relict permafrost (relates to an earlier colder climate)

9 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Latitudinal Changes Transect running up through the Mackenzie Valley to the Canadian Arctic (right to left). Figure From: Selby, M.J. 1985. Earth’s Changing Surface. OUP, Oxford (p.392). © Oxford University Press

10 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Continuous Permafrost is ubiquitous, except beneath large water bodies e.g. massive ice at Peninsula Point, Mackenzie Delta, Canadian NWT (70°N) R.I. Waller

11 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Discontinuous Permafrost restricted to distinct “islands”. Often found in peatlands. Palsas in a valley mire near Iitto, Northern Finland (68°N) R.I. Waller

12 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Permafrost and Climate R.I. Waller

13 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Permafrost and Climate Extent and distribution of permafrost is determined principally by climate (MAAT - Mean Annual Air Temperature). In general, lower temperatures promote more widespread and deeper permafrost layers. Climate also influences the active layer - warmer temperatures promote a longer lasting and thicker active layer. Thickest permafrost occurs in Northern Siberia: up to 1600 m thick (c. 1 mile). http://www.unep.org/GC/GC21/permafrost_map.jpg

14 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Permafrost depth vs. MAAT Note: not a straightforward relationship Data from: French, H.M. 2007. The Periglacial Environment (3rd ed.). Wiley & Sons, Chichester

15 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Key Variables Mean Annual Air Temperature (MAAT) Determined solely by the prevailing climate. Mean Annual Ground Temperature (MAGT): Measured at point where seasonal temperature fluctuations cease. Key control of permafrost thickness. Dependent upon climate, surface characteristics and thermal properties of the ground. http://photojournal.jpl.nasa.gov/catalog/PIA12098

16 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Ground Thermal Regime After: French, H.M. 2007. The Periglacial Environment (3 rd ed.). Wiley & Sons, Chichester. P.84

17 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions MEAN ANNUAL AIR TEMP. MEAN ANNUAL GROUND TEMP. Related variable Subject of lecture 3 Complex relationship CLIMATE GROUND SURFACE TEMP. PERMAFROST THICKNESS GROUND THERMAL REGIME

18 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Permafrost Distribution and Climate Some general rules: MAGT is generally 3-4°C higher than MAAT - N.B. not constant, varies with surface conditions. Southern limit of continuous permafrost: approximates to the -6 to - 8°C MAAT isotherm and the -5°C MAGT isotherm. Southern limit of discontinuous permafrost: approximates to the -1°C MAAT isotherm. Between -1 and -4°C isotherms, permafrost occurrence is restricted to particular areas, e.g. north facing slopes. Smith, S.L. and Burgess, M.M. (1999) ‘Mapping the sensitivity of Canadian permafrost to climate warming’; Interactions between the Cryosphere, Climate and Greenhouse Gases (proceedings of the IUGG 99 Symposium HS2) IAHS Publ no. 256 www.iahs.info/redbooks/256.htm

19 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Small-Scale Factors Broad range of local factors influence the distribution and thickness of permafrost, e.g.: –Relief and slope orientation. –Rock and soil properties. –Presence and type of vegetation. –Duration and thickness of snow cover. Complicate the relationship between climate and permafrost thickness. http://www.flickr.com/photos/cpurrin1/3823331670/

20 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Surface Boundary Conditions Mean annual ground temperature profiles at seven sites near Yellowknife, with contrasting ground surfaces. From: Brown, R.J.E. (1973) ‘Influence of climatic and terrain factors on ground temperatures at three locations in the permafrost region of Canada’ Proceedings of the Second International Conference on Permafrost, Yakutsk, USSR, North American Contribution pp27-34. Washington DC: National Academy of Sciences Fig 8 pg. 33

21 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Additional Factors Regional relationship between air temperature and permafrost extent/thickness is affected by the operation of additional factors, including: –Presence of large water bodies: associated with taliks. –Past climate regime: thick permafrost requires long periods of time to form; therefore thick sequences can reflect cooler temps. during the Pleistocene. –Thermal discontinuities: Discontinuities associated with faults, hot springs etc. can produce localised changes in permafrost extent and thickness. http://commons.wikimedia.org/wiki/File:Black_Fish_Lake.jpg

22 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Permafrost and Landforms The type of permafrost zone also influences the landforms present… Figure From: Harris, S.A. 1986. The Permafrost Environment. Croom Helm, Beckenham (p.13). © Croom Helm Publishers

23 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Continuous Permafrost Massive ground ice, sand wedges and ice wedges... R.I. Waller

24 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Discontinuous Permafrost Patterned Ground R.I. Waller

25 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Palsas R.I. Waller

26 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Blockfields R.I. Waller

27 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions Lecture Summary Study of permafrost environments is associated with a set of key terms including: talik, permafrost table and active layer. Three main permafrost zones: continuous, discontinuous and sporadic. Zones show latitudinal and altitudinal changes that are associated primarily with climate but also with a series of secondary variables. Each permafrost zone tends to be associated with a distinctive suite of geomorphological processes and landforms.

28 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions References French, H.M. 2007. The Periglacial Environment (3 rd ed.). Wiley & Sons, Chichester. Harris, S.A. 1986. The Permafrost Environment. Croom Helm, Beckenham. Selby, M.J. 1985. Earth’s Changing Surface. OUP, Oxford. Williams, P.J. and Smith, M.W. 1989. The Frozen Earth. Studies in Polar Research. CUP, Cambridge.

29 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions This resource was created by the University of Keele and released as an open educational resource through the 'C-change in GEES' project exploring the open licensing of climate change and sustainability resources in the Geography, Earth and Environmental Sciences. The C-change in GEES project was funded by HEFCE as part of the JISC/HE Academy UKOER programme and coordinated by the GEES Subject Centre. This resource is licensed under the terms of the Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales license (http://creativecommons.org/licenses/by-nc-sa/2.0/uk/).http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ However the resource, where specified below, contains other 3rd party materials under their own licenses. The licenses and attributions are outlined below: 1.Slide 7 – Figure showing surface geotherms from Harris, S.A. 1986. The Permafrost Environment. Croom Helm, Beckenham, is the copyright of Croom Helm Publishers. Permission should be sought from the copyright holders prior to re-use 2.Slide 9 – Figure showing a transect through the MacKenzie Valley from Selby, M.J. 1985. Earth’s Changing Surface. OUP, Oxford, is the copyright of Oxford University Press. Permission should be sought from the copyright holders prior to re-use 3.Slide 22 – Figure showing permafrost zones and landforms from Harris, S.A. 1986. The Permafrost Environment. Croom Helm, Beckenham, is the copyright of Croom Helm Publishers. Permission should be sought from the copyright holders prior to re-use 4.The name of Keele University and its logos are unregistered trade marks of the University. The University reserves all rights to these items beyond their inclusion in these CC resources. 5.The JISC logo, the C-change logo and the logo of the Higher Education Academy Subject Centre for the Geography, Earth and Environmental Sciences are licensed under the terms of the Creative Commons Attribution -non-commercial-No Derivative Works 2.0 UK England & Wales license. All reproductions must comply with the terms of that license

30 Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk C-Change in GEES: Changing Permafrost Environments – Permafrost Definitions AuthorDr Richard Waller Stephen Whitfield Institute – OwnerKeele University, School of Physical and Geographical Sciences TitlePermafrost Definitions PowerPoint Presentation Date CreatedMarch 2010 DescriptionPart Two of Changing Permafrost Environments Educational Level3 Keywords (Primary keywords – UKOER & GEESOER) UKOER, GEESOER, zones, climate, terminology, ground thermal regime, continuous, discontinuous, active layer, processes, landforms Creative Commons LicenseAttribution-Non-Commercial-Share Alike 2.0 UK: England & Wales Item Metadata


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