Cool, CALM, collected: the Circumpolar Active Layer Monitoring program and network

ABSTRACT The Circumpolar Active Layer Monitoring (CALM) program is the primary global-change monitoring program concerned with the seasonally frozen active layer above permafrost. The active layer has been designated by the Global Climate Observing System and the Global Terrestrial Observing Network as an ‘Essential Climate Variable’. CALM was launched in 1991 on a volunteer basis in cooperation with the International Tundra Experiment. CALM observatories in Russia and Alaska have been supported since 1998 by the U.S. National Science Foundation through five consecutive five-year funding cycles. In its current configuration, the CALM network includes observation sites throughout the circum-Arctic region and a substantial number of sites in Antarctica. Open access to data and data harmonization are hallmarks of the program. In addition to its ongoing emphasis on field observations of active-layer thickness, temperature, soil moisture, and thaw subsidence are currently being monitored at many sites. Increased emphasis is being placed on observing the dynamics of other landscape and ecosystem parameters, including vegetation, landscape patterns, and soils. Other developing features of the program include expanded education and outreach activities, close cooperation with other international programs, and provision of quality-controlled, standardized data products that meet the needs of the wider scientific community.