An international program concerned with monitoring the active layer is now formally designated CALM (Circumpolar Active Layer Monitoring). The program is closely affiliated with the International Tundra Experiment (ITEX), the International Permafrost Association (IPA), and several IPA working groups. Data obtained through this coordinated program are important indicators of landscape variability, provide documentation of interannual and decadal fluctuations, and serve as a basis for intersite comparisons of ecosystem structure and function. Data also serve to validate models at local, regional, and global scales. The CALM sites also can provide ground truth for the GTOS-GCOS program and IGBP high-latitude transects.

At present, CALM consists primarily of sites where maximum active-layer thickness is measured at least once at the end of the summer, by physically probing on grids ranging in size from 10 meters to 1000 meters. Other types of observations are from frost tubes, single point measurements repeated at the same location annually, and soil temperature recordings at multiple depths. Presently CALM sites include several north-south transects in northern North America and an east-west array of sites in Eurasia. Some sites include data from soil temperature recorders and shallow boreholes for temperature measurements. The accompanying map and table show the location of some 45 sites in the network, with maximum thaw data as available since 1991.

Several sites have collected data starting in the 1960s (Barrow, Pearl Creek) and the 1970s (Abisko and Svalbard). Some sites are temporarily inactive, others may be eliminated owing to funding constraints and programmatic changes, and a few did not have 1996 data available. Additional sites in mid-latitude mountains and in Antarctica will be added to the network in 1997. PLEASE RECOMMEND NEW SITES FOR INCLUSION IN CALM. CRITERIA FOR INCLUSION IN CALM ARE: PERMAFROST UNDERLIES SITE; IS EXISTING SITE LIKELY TO CONTINUE OPERATING AND TO PROVIDE DATA, OR NEW, LONG -TERM SITES TO BE ESTABLISHED. The following information should be provided (forms available with poster):

1. Site name.
2. Site history. Existing ____; Year started ______; New ______.
3. Responsible individual(s) for data collection; email and fax address:
4. Latitude and longitude.
5. Elevation above sea level (meters).
6. Slope and aspect of CALM site(s).
7. Landform or geomorphological description of area occupied by CALM site(s).
8. Predominant texture of soil (sand, gravel, peat, etc.).
9. Vegetation classification (dominant vegetation type, percentage of vegetation, bare ground, etc.).
10. Information on permanent temperature an/or moisture installations (probes, recorders, depth of sensors, etc.); if possible provide annual average values (or ranges) of these data.
11. Name and location (lat/long) of closest climate station; provide mean monthly air temperatures and snow depth as available for years of CALM measurements.

The IPA News Bulletin "Frozen Ground" and the IPA Web site are being used to disseminate the data to interested parties. Data will be archived annually in and available from the IPA Global Geocryological Database (GGD). See poster by Hanson et al. for brief description of GGD and the associated Circumpolar Active-layer Permafrost System (CAPS) CD-ROM. The CALM sampling protocols, site descriptions, and complete data sets through 1997 will be part of the CAPS CD-ROM.

Jerry Brown
International Permafrost Association
P.O. Box 7
Woods Hole, MA 02543
TELEPHONE: 508 457 4982  
Temporary fax 508 457 1548
E-mail: jerrybrown@igc.apc.org

Alan E. Taylor
2313 Mills Road
Sidney, BC V8L 2C4, Canada

Frederick E. Nelson
Department of Geography and Planning
State University of New York at Albany
Albany, NY 12222

Kenneth M. Hinkel
Department of Geography
University of Cincinnati
Cincinnati, OH 45221