Microtopographic patterns in an arctic baydjarakh field: Do fine-grain patterns enforce landscape stability?

John A. Gamon, G. Peter Kershaw, Scott Williamson, David S. Hik

Research output: Contribution to journalArticlepeer-review

Abstract

Recent observations suggest that while some arctic landscapes are undergoing rapid change, others are apparently more resilient. In this study, we related surface cover and energy balance to microtopography in a degraded polygonal peat plateau (baydjarakh field) near Churchill, Manitoba in mid-summer 2010. The landscape consists of remnant high-centered polygons divided by troughs of varying widths. Historical aerial photos indicate these topographical features have been stable for over 80 years. Our goal was to explore patterns that might explain the apparent stability of this landscape over this time period and to evaluate remote sensing methods for characterizing microtopographic patterns that might resist change in the face of climate warming. Summertime surface albedo measurements were combined with several years of winter snow depth, snow heat flux, summer thaw depth and annual surface temperature, all of which had striking contrasts between wet troughs and high polygon centers. Measurements of albedo and the snowpack heat transfer coefficient were lowest for wet troughs (areas of standing water) dominated by graminoids, and were significantly higher for high polygon centers, dominated by dwarf shrubs and lichens. Snow depth, surface temperature and thaw depth were all significantly higher for wet troughs than high polygon centers. Together these patterns of cover and energy balance associated with microtopographic variation can contribute to the stability of this landscape through differential heat transfer and storage. We hypothesize that local thermal feedback effects, involving greater heat trapping in the troughs than on the baydjarakh tops, and effective insulation on the baydjarakh edges, have ensured landscape stability over most of the past century. These results suggest that high-resolution remote sensing, combined with detailed field monitoring, could provide insights into the dynamics or stability of arctic landscapes, where cover often varies over short distances due to microtopographic effects.

Original languageEnglish (US)
Article number015502
JournalEnvironmental Research Letters
Volume7
Issue number1
DOIs
StatePublished - Mar 2012
Externally publishedYes

Keywords

  • albedo
  • arctic tundra
  • baydjarakh
  • high-centred polygons
  • landscape stability
  • microtopography
  • permafrost
  • remote sensing
  • thermal properties
  • vegetation cover

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Environmental Science(all)
  • Public Health, Environmental and Occupational Health

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