Model Output Assessing Net Carbon Exchange Across the Arctic Tundra-Boreal Forest Transition in Alaska, 1981-2000

Summary

In this study, investigators simulated the temporal and spatial patterns of net carbon exchange in Alaskan ecosystems that span the transition from Arctic tundra to boreal forest. They modeled net carbon storage in terrestrial ecosystems by the balance between net primary production (NPP) and decomposition. They also modeled vegetation and soil carbon and nitrogen pools in tundra, shrub tundra, and tree line evergreen conifer forest ecosystems. Field data were used to develop parameterizations for the Terrestrial Ecosystem Model (TEM) 5.0. Investigators extrapolated the model spatially over the Alaskan Arctic to boreal tree line to simulate changes in vegetation and soil carbon storage from 1981-2000 (Thompson et al. 2005).

Data are in Microsoft Excel Comma Separated Values format and are available via FTP.

Citing These Data

Chapin, III, F. S, T. Osterkamp, V. Romanovsky, and A. D. McGuire. 2007. Model output assessing net carbon exchange across the Arctic tundra-boreal forest transition in Alaska, 1981-2000. Boulder, Colorado USA: National Snow and Ice Data Center. Digital media.

Overview Table

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Acquisition and Processing
4. References and Related Publications
5. Document Information

1. Contacts and Acknowledgments

Investigators

F. Stuart Chapin, III
Institute of Arctic Biology
311 Irving I
University of Alaska
Fairbanks, AK 99775
USA

Thomas Osterkamp
Geophysical Institute
University of Alaska
Fairbanks, AK 99775
USA

Vladimir Romanovsky
Department of Geology and Geophysics
Natural Sciences Facility, 900 Yukon Drive
P.O. Box 755780
Fairbanks, AK 99775-5780

A. Dave McGuire
U.S. Geological Survey
Alaska Cooperative Fish and Wildlife Research Unit
University of Alaska
Fairbanks, AK 99775
USA

Acknowledgements

This research was funded by the National Science Foundation (NSF) Office of Polar Programs (OPP) grant 9732126 awarded to F. Stuart Chapin.

2. Detailed Data Description

File Structure

Data files contain 16 columns corresponding to longitude, latitude, year, total, and each of the twelve months in a year. Flux data are reported in units of grams of carbon per square meter per month (g_Cm^-2month^-1). Pool data are measured in grams of carbon per square meter (g_Cm^-2).

File Naming Convention

The file naming convention is param-zclass.csv, where

param = net primary production (npp), heterotrophic respiration (R_h), net ecosystem production (nep), or vegetation carbon (vegc)
zclass = tundra, forest, or shrub

For example, npp-tundra.csv contains the NPP data for the tundra.

The vegcount.readme ASCII text file contains instructions on how to reconstruct the vegetation data in vegcount.csv.

Spatial Coverage

North Slope, northern Alaska

Southernmost Latitude: 65.5° N
Northernmost Latitude: 69.0° N
Westernmost Longitude: 167.5° W
Easternmost Longitude: 141.5° W

Grid Description

Investigators ran the model for the area of northern Alaska that extends from the Arctic Ocean to the tundra-boreal forest ecotone. The model domain encompasses 418 0.5° x 0.5° (latitude x longitude) grid cells (Thompson et al. 2005).

Temporal Coverage

The simulation began in 1900 and ran through 2000. Investigators only evaluated the results from 1981-2000, a time period when the climate has warmed dramatically (Serreze et al. 2000).

Temporal Resolution

Monthly

Quality Assessment

Please refer to Thompson et al. 2005 for quality assessment information.

4. Data Acquisition and Processing

Data Acquisition Methods

These data are simulated estimates from the Terrestrial Ecosystem Model of NPP, R_h, NEP, and vegetation carbon. Investigators performed three simulations, each simulation was with a different parameterization (forest, tundra, shrub). They aggregated the variables based on a vegetation map. The analyses include total NPP, R_h, and NEP from 1981-2000, change in carbon pools, and various trend analysis with the fluxes, pool, and climate factors. The climate data were obtained from the Climate Research Unit (CRU) data set.

The vegetation data used for the model simulation combines several 1 km resolution vegetation maps for the North Slope (Muller, et al. 1999), Seward Peninsula (visit the Arctic Geobotanical Atlas), and areas not covered in those two maps (visit the High-Latitude Climate Transects site). Investigators reclassified each 1 km vegetation pixel as tundra, shrub tundra, or forest. The spatial domain consisted of 79% tundra, 13% shrub, and 8% forest.

Processing Steps

Please refer to Thompson et al. 2005 for information on data processing.

5. References and Related Publications

Muller, S. V., A. E. Racoviteanu, and D. A. Walker. 1999. Landsat MSS-derived land-cover map of northern Alaska: extrapolation methods and a comparison with photo-interpreted and AVHRR-derived maps. International Journal of Remote Sensing 20, 2921-2946.

Serreze, M. C., J. E. Walsh, F. S. Chapin, III, T. Osterkamp, M. Dyurgerov, V. Romanovsky, W. C. Oechel, J. Morison, T. Zhang, and R. G. Barry. 2000. Observational evidence of recent change in the northern high latitude environment. Climatic Change 46, 159–207.

Thompson, C. C., A. D. McGuire, J. S. Clein, F. S. Chapin, III, and J. Beringer. 2005. Net carbon exchange across the Arctic tundra-boreal forest transition in Alaska 1981-2000. Mitigation and Adaptation Strategies for Global Change 11:805-827. doi: 10.1007/s11027-005-9016-3.

6. Document Information

Acronyms and Abbreviations

The following acronyms and abbreviations are used in this document.

Document Creation Date

March 2007

Document URL

http://data.eol.ucar.edu/codiac/dss/id=106.arcss162