Modelling the spatial distribution of permafrost in Labrador-Ungava using TTOP

• Main Authors: Way, Robert G., Lewkowicz, Antoni G.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2016
• Subjects: Canada; permafrost; Subarctic
• Online Access: http://hdl.handle.net/1807/73766; http://www.nrcresearchpress.com/doi/abs/10.1139/cjes-2016-0034

Permafrost zonation in Labrador-Ungava ranges from very isolated patches through to continuous. Here we present a new estimate of the distribution of permafrost at high resolution (250 m x 250 m) using spatial numerical modelling supported by station data from 29 air and ground climate monitoring stations. Permafrost presence was estimated using a modified version of the temperature at the top of permafrost (TTOP) model. Mean ground surface temperatures were modelled using gridded air temperatures and a novel n-factor parameterization scheme that compensates for regional differences in continentality, snowfall and land cover and is transferable to other Subarctic environments. The thermal offset was modelled using land cover and surficial material datasets. Predicted TTOP temperatures for the average climate range regionally from -9°C (for high elevations in northern Québec) to +5°C (for southeastern Labrador-Québec). Modelling for specific temporal windows (1948-1962; 1982-1996; 2000-2014) suggests that permafrost area increased from the middle of the 20th Century to a potential peak extent (36% of the total land area) in the 1990s. Subsequent warming is predicted to have caused a decrease in permafrost extent of one-quarter (95 000 km2), even if air temperatures rise no further, providing air and ground temperatures equilibrate. Zonal boundaries derived by upscaling the high-resolution model are highly scale dependent, precluding direct comparison with the Permafrost Map of Canada that was generated without the use of geographic information system based analyses. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.