Applications of Measurements at Permafrost Monitoring Sites for Documenting Long-Term Change in Denali, Wrangell-St. Elias, and Yukon-Charley Rivers National Parks and Preserves

Osterkamp, T.

The extent and state of permafrost within the three park units of the Central Alaska Network (CAKN) are vital signs of interest to the National Park Service (NPS). This report explores potential applications of observations and measurements of permafrost in the CAKN-NPS monitoring program. Observations and measurements at a few sites illustrate how the data can be used. Since permafrost conditions vary significantly throughout Alaska, the recommendations made here may not be valid for other park units. Air temperatures in Alaska warmed during the first half of the 20th century, cooled during the 3rd quarter and warmed sharply during the 4th quarter. Climate models predict that this recent warming will increase and continue well into the 21st century. Permafrost has generally warmed coincident with warming air temperatures. In many areas south of the Arctic Circle, permafrost is currently thawing with the formation of thermokarst terrain. Thermokarst terrain drastically modifies and remolds the ground surface. This process can modify or totally change ecosystems, human activities, infrastructure, and the fluxes of energy, moisture and gases across the ground surface-air interface. In lowlands or relatively flat areas, a shift from boreal forests to shrubby wetlands or grasslands often occurs with concurrent changes in bird and animal populations. The new ecosystems favor aquatic birds and mammals. This report makes recommendations to determine what changes have already occurred, to monitor these changes, to determine the current status (thermal regime) of the permafrost, and to monitor its thermal regime through observations and measurements. The specific, prioritized recommendations are: • Conduct a literature search, especially of gray literature that exists in federal and state agencies that have performed permafrost related research in Alaska. • Add permafrost observations and measurements to selected existing or proposed study sites within the parks. • Determine the current extent of thermokarst by identifying areas where ice-rich permafrost is degrading using aerial photo analyses and field investigations. • Determine the rates and characteristics of change associated with thermokarst terrain by establishing a thermokarst monitoring site in each park. • Determine the current state (thermal regime) and recent changes in it by establishing at least one permafrost monitoring site in each park. • Develop a predictive capability (thermal model) for each park that incorporates ecosystem characterisics. • Archive data in the National Snow and Ice Data Center at Boulder, Colorado.