Active Layer - Sirmilik

Permafrost and the active layer (the soil layer above the permafrost that freezes and thaws annually) are directly affected by climate. It is anticipated that rising temperatures in the Arctic will lead to permafrost warming/melt and thickening of the active layer. Probable impacts of permafrost degradation on the tundra ecosystem include ground instability and changes to local hydrological patterns and surface vegetation. In 2008 and 2009, a Circumpolar Active Layer Monitoring (CALM) Grid was installed at two sites, one on Bylot Island and another on the Borden Peninsula, in Sirmilik National Park as part of an international program to monitor the effects of climate change on the active layer and near-surface permafrost. Active layer thickness measurements are taken each summer, at 100 points within the 100 m x 100 m grid, using a metal probe. Active layer depth measurements, thaw depth at the time of monitoring and maximum thaw depth, are also monitored using a thaw tube. To examine the thermal characteristics of the soil active layer, HOBO Micro Stations, with one above-ground and 5 below-ground temperature sensors, were installed nearby the CALM Grids in 2012. The temperature data, recorded every 2 hours throughout the year, are downloaded from dataloggers on an annual basis.