A METHOD TO ESTIMATE ACTIVE-LAYER THICKNESS ON THE BASIS OF CORRELATIONS BETWEEN TERRAIN AND CLIMATIC PARAMETERS AS MEASURED IN NORTHERN QUEBEC

Field studies recently conducted on the west coast of Ungava Bay, in the southern part of the continuous permafrost zone, have permitted the establishment of the pattern of active-layer development for six different geomorphological and vegetational terrain types. Thermal properties for organic and mineral soil, and for bedrock, were calculated from field data. A linear regression was established for each group of sites between the logarithmic transformation of thaw penetration and an atmospheric thawing index obtained through interpolations of air temperature data form the two closest meteorological stations - Kuujjuaq (Fort Chimo) and Koartaq (Cape Hope's Advance). This regression was then used to estimate the total thickness of the active layer at the end of the thaw season for each terrain type, and to assess probable variations in active-layer depths in the region over a 20 year time period.