TITLE: Toolik Snowfence Experiment: 1994-2001 Active layer depth PRINCIPAL INVESTIGATOR: Dr. Marilyn Walker Leader, Boreal Ecology Cooperative Research Unit USFS PNW Research Station and University of Alaska Fairbanks Boreal Ecology Cooperative Research Unit School of Agriculture and Land Resources Management P.O. Box 756780 University of Alaska Fairbanks Fairbanks, AK 99775-6780 Phone: 907-474-2424 Fax: 907-474-6251 E-mail: ffmdw@uaf.edu FUNDING SOURCE: National Science Foundation ARCTIC SYSTEM SCIENCE PROGRAM: Land-Atmosphere-Ice Interactions (LAII) and The International Tundra Experiment (ITEX) GRANT TITLES AND GRANT NUMBERS: 1994 - 1998: OPP-9400083 -- ITEX / Comparative Responses of Moist and Dry Arctic Tundra to Altered Snow and Temperature Regimes 1999 - 2003: OPP-9907127 -- ITEX / Collaborative Research: Species Responses to Changes in Climate Across Arctic Gradients Using the North America ITEX Network (NATEX): Influences On Community and Ecosystem Processes 1999 - 2003: OPP-9996383 -- ITEX / Comparative Responses of Moist and Dry Arctic Tundra to Altered Snow and Temperature Regimes CONDITIONS FOR USE AND CITATION: For permission to use these data, contact the Principal Investigator. Grant numbers must be cited in any manuscripts resulting from these data. In addition, a copy of the manuscript must be sent to the PI. DATA SET OVERVIEW: This file contains active layer data collected for the Toolik Snowfence Experiment from 1994 to 2001. The Toolik Snowfence Experiment (part of the International Tundra Experiment network) examines the short- and long-term effects of increased snow depth (shortened growing season) and increased summer temperature on arctic tundra vegetation. The goal of this project is to assess potential changes in tundra plant communities in response to global climate change. Time period covered by data: 19940811 to 20010824 Physical location of measurement: Toolik Field Station, Alaska USA (68.62710 N, 149.59322 W) DATA COLLECTION AND PROCESSING: Active layer is measured to the nearest cm with a stainless steel probe that is forced into the ground until it hits the top of the permafrost. The distance that the probe is pushed into the ground from the soil surface is the depth of the active layer. Data were collected in zones 0, 1, 3 and 5 at the moist tussock site only. The soil at the dry heath site is too rocky to accurately measure the active layer. In each zone, 3 plots per warming treatment are monitored approximately once per week over the field season. Six random measurements are taken at each plot; three tussock and three intertussock. See the data remarks section below for annual variation of this method. The Toolik Snowfence Experiment's design and manipulation are described further in: Walker, M. D., D. A. Walker, J. M. Welker, A. M. Arft, T. Bardsley, P. D. Brooks, J. T. Fahnestock, M. H. Jones, M. Losleben, A. N. Parsons, T. R. Seastedt and P. L. Turner. 1999. Long-term experimental manipulation of winter snow regime and summer temperature in arctic and alpine tundra. Hydrological Processes 13: 2315-2330. DATA FORMAT: File name: USTOOLIK_activelayer94-01.txt SUMMARY OF VARIABLES FOR 1994-2001 DATA 1. SITE: country/site/project title 2. DATE: date of data collection (YYYYMMDD) 3. LOCATION: site; moist only 4. ZONE: 0-6 5. PLOT: unique plot number 6. TREATMENT: ITEX warming treatment 7. REPLICATE: sequential numbering of samples 8. TUSSOCK_DEPTH (cm) 9. INTERTUSSOCK_DEPTH (cm) DESCRIPTION OF SELECT VARIABLES SITE USTOOLIK: Toolik Field Station, Alaska, USA; Comparative responses of moist and dry arctic tundra to altered snow and temperature regimes LOCATION Research site: Snowfences are erected and grids established at both a moist tussock site (68.62032 N, 149.59931) and a dry heath site (68.62261 N, 149.59589 W). In addition, monitored plots are established where a natural snowdrift occurs. This site is referred to as the snowfield. ZONE Snow manipulation: A 60 m snowfence is aligned on an east-west axis at both the moist and dry sites. Both snowfences are perpendicular to the predominant winter winds from the Brooks Range to the south, effectively creating a leeward drift 50-60 m long on the north side of the fence. An established grid on the north side of the fence divides the drift into 6 parallel zones (60 m x 10 m). Zone number increases from 1 to 6, as distance from the snowfence increases. Zones 1, 2 and 3 accumulate the most snow (2-3 m), while zones 4, 5 and 6 accumulate the least snow (0.5-2 m). Zone 0 (the control) is located adjacent to the snowfence grid and does not receive supplemental snow. TREATMENT ITEX warming treatment. OTC: Open-topped chamber (warming), CTL: No chamber (control). CODES USED IN DATA SET In all years "-9999" indicates missing data. DATA REMARKS: Only a single tussock and intertussock measurement per plot were collected in 1994 and 1995. Although the zones sampled were consistent from 1994 to 2000, the actual plots sampled varied in 1994 and 1995. Only maximum thaw depth was recorded in 1994. Active layer data collected in 1996 is not archived here due to flawed methods. LOCATION OF ORIGINAL DATA SHEETS: Boreal Ecology Cooperative Research Unit, University of Alaska, Fairbanks, Alaska, USA DOCUMENTATION AUTHOR: Original: Amy Breen Carroll, 29 March, 2001 Updated by: Amy Breen Carroll, 20 December, 2001 Updated by: Amy Breen Carroll, 18 February, 2002 PRINCIPAL FIELD WORKERS: Andrew Borner PRINCIPAL POSTDOCS: Michael H. Jones Anna Arft PUBLICATIONS WHICH INCLUDE THESE DATA: None to date.