Permafrost modeling in Alaskan National Park Lands

Permafrost is pervasive in Alaska’s National Parks, Preserves, and Monuments. Nearly 40 million acres of Alaska’s NPS units lie within the zone of continuous or discontinuous permafrost. This area constitutes over 70% of Alaska’s NPS land and nearly half of all the NPS administered land in the US. Much of this permafrost is vulnerable to major changes due to climatic warming because 1) it has temperatures within a few degrees of freezing, such that relatively minor warming could destabilize it entirely, or 2) it contains ice-rich material near the surface that could thaw with climatic warming, leading to major reconfiguration of the landscape.

Permafrost is a subsurface feature that is difficult to observe and map directly and temperature measurements are required to determine the status of permafrost. Existing information about the extent and temperature of permafrost in NPS units is limited due to the lack of borehole observations on NPS lands. Modeling of permafrost extent has proven very useful for extrapolating between the very widely spaced boreholes where direct observations are made. Permafrost distribution and the thickness of the active layer can be modeled, given sufficient data about soil and ground properties, vegetation, topography, atmospheric climate, and soil temperatures. The same models used to map current permafrost distribution and active layer thickness can be used to predict the future climate state of permafrost by using projected climate forcing and scenarios.

Geophysical Institute Permafrost Laboratory (GIPL) at University of Alaska Fairbanks has developed a model, "GIPL 1.0 - Spatially Distributed Model of Permafrost Dynamics in Alaska”, that has successfully mapped permafrost distribution and active-layer thickness at kilometer scale for the State of Alaska. As a part of its inventory and monitoring program, the NPS has obtained or is in the process of gathering data that could be used to make improved runs of the GIPL 1.0 model for NPS units in Alaska.