Évolution spatio-temporelle du pergélisol alpin marginal au mont Jacques-Cartier, massif des Chic-Chocs, Gaspésie (Qc)
The objective of the study was to acquire detailed knowledge of the spatial evolution of the ground surface temperature (GST) on Mont Jacques-Cartier and the thermal response of its marginal permafrost body to the past and future climate changes. The study is based on temperature (GST, underground) and snow measurements, and spatial modeling of the potential GST distribution and numerical modeling of the ground thermal regime. The result showed that the spatio-temporal variability of the GST over the summit is mainly correlated with the snowpack distribution. On the wind-exposed plateau, the snowpack is thin and discontinuous. The GST is thus closely connected to the very cold air temperature in winter. In the krummholz patches and in the topographic depression on the leeward slope, drifted snow accumulation is significant leading to surface condition warmer than over the wind-exposed plateau. Because of the near snow-free condition of the plateau summit and the highly conductive nature of its bedrock, the response of the permafrost to the climate signal is rapid. From 1978 to 2014, the ground warmed at all depths. If the recent trend continues as predicted by the climate simulations provided by the Ouranos consortium, the complete disappearance of the permafrost body at Mont Jacques-Cartier could occur around 2040-2050.
Mountain permafrost Snow Ground surface temperature Climate changes