USGS Contributions to the Climate Change Science Program

PERMAFROST MONITORING

The Department of Interior's (DOI) permafrost network in Alaska is part of a global network of permafrost monitoring stations (GTN-P) designed to monitor for changes in the solid-earth component of the earth's cryosphere. Changes in permafrost temperature and active-layer thickness reflect changes in surface climate over time, and therefore serve as useful indicators of climate change. GTN-P is one of several global networks designed to monitor for changes in the terrestrial component of the earth's climate system. The GTN-P network is able to monitor the active layer (the surface layer that freezes and thaws annually) and the thermal state of the underlying permafrost. Active layer measurements are made using automated semi-permanent surface instrument stations, whereas the deeper permafrost is monitored through periodic downhole temperature measurements in boreholes. DOI's contribution to GTN-P results from collaboration among USGS, U.S. Bureau of Land Management, and U.S. Fish and Wildlife Service.

Thumbnail chart showing permafrost temperatures versus depth

Temperature profile from one of 21 deep boreholes in the NPRA array showing the response of permafrost to the significant warming of the 1990's.

Image of Northern Alaska showing bore hole permafrost sites in relation to NPRA and ANWR Photo of downhole sensors in Northern Alaska

The subsurface permafrost monitoring network currently covers federal lands in and near the National Petroleum Reserve Alaska (NPRA). Subsurface temperatures are measured periodically with downhole sensors that indicate the depth and thickness of the active layer and permafrost, and yield subsurface temperature profiles. These measurements are important for determining the long-term terrestrial response to climate change.

Image of Northern Alaska showing active layer monitoring sites in relation to NPRA and ANWR Photo of monitoring station

DOI's active-layer monitoring network spans federal lands in the National Petroleum Reserve Alaska (NPRA) and the Arctic National Wildlife Refuge (ANWR). Most of the stations depicted here were installed in 1998. Current plans call for an expansion of the network to improve spatial coverage on federal lands. In its current configuration, stations in the network monitor continuously for: changes in active-layer and shallow permafrost temperatures (5-120 cm depths); active-layer thaw depth; air temperature; snow depth; duration of seasonal snow cover; and cloudiness.

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U.S. Department of the Interior | U.S. Geological Survey
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