FILE NAME: gemtem-00.doc YEARS: 1920-2100 PI: A. Dave McGuire OTHERS: Joy Clein, Bonnie Kwiatkowski, John Hobbie, Ed Rastetter MANUSCRIPT TITLE: Modeling carbon responses of tundra ecosystems to historical and projected climate: A comparison of a plot- and a global-scale ecosystem model to identify process-based uncertainties BRIEF DESCRIPTION: This data set contains the model output data of GEM and TEM simulations from 1920-2100 for Toolik Lake Alaska. RESEARCH LOCATION: Toolik Lake Alaska is located on the north side of the Brooks Range, 68 degrees 38N, 149 degrees 38'W. METHODS: TEM simulates C and N fluxes and pools at a monthly time scale, while GEM simulates C and N fluxes and pools at an annual time scale. The values of several ecosystem variables are compared between the 2 models. These results are presented and discussed in Clein, et al. (2000). TEM uses the moist tundra calibration developed by McGuire et al. (1992) based on data from Toolik Lake, Alaska, and GEM uses the tussock tundra calibration developed by McKane et al. (1997) for Toolik Lake, Alaska . MODEL NAME: TEM, version 41e as described in McGuire et al. (1999) with modifications as described in McGuire et al. (2000), and a version of TEM (TEM fast soil C) with a higher soil CN ratio (fast soil C), and MBL-GEM described in Rastetter, et al., 1991 MODEL INPUT: TEM requires 7 driver or input variables. These are atmospheric CO2, temperature, precipitation, mean monthly cloudiness, vegetation, elevation and soil texture as percent sand, silt and clay. MBL-GEM requires 5 driver or input variables. These are atmospheric CO2, growing season temperature, growing season percent water filled pore space (% WFPS), growing season photosynthetically active radiation (PAR), and nitrogen inputs. Values for each of these drivers were used from various global data sets, ie: CO2 (1920-1994; Enting et al 1994, 1995-2100; Hadley CM2 simulation), temperature and precipitation (1920-1994; Legates & Wilmott 1990a, 1990, with the anomalies of Jones 1994 and Hulme 1995, 1995-2100; monthly ramps from a Hadley Center CM2 simulation), vegetation (moist tundra), elevation (NCAR/Navy 1984), soil texture (FAO-UNESCO 1971), cloudiness (Leamans & Cramer 1991), nitrogen input was 0.06 g N m-2 yr-1. For more detailed information see McGuire et al. 2000. PAR and %WFPS for GEM were simulated by TEM. CONDITIONS FOR USE: Acceptance and utilization of this data requires that: The Principal Investigator is sent a notice stating reasons for acquiring any data and a description of the publication intentions. The Principal Investigator of the data set be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications. A copy of any resultant publications should be sent to: A Dave McGuire 216 Irving I Building University of Alaska Fairbanks Fairbanks, AK 99775 VARIABLE DESCRIPTION: Variable name Variable description Units ---------------------------------------------- NPP Net Primary Production g C m-2 yr-1 RH Heterotrophic Respiration g C m-2 yr-1 NEP Net Ecosystem Production g C m-2 yr-1 NMIN Net Nitrogen Mineralization g N m-2 yr-1 SoilC Soil Organic Carbon g C m-2 VegC Vegetation Carbon g C m-2 FOR MORE INFORMATION, CONTACT: A Dave McGuire 216 Irving I Building, University of Alaska Fairbanks Fairbanks, AK 99775 Email: ffadm@uaf.edu FILES: File Name: gemtem00-NPP.dat File Type: Comma-delimited ASCII File Name: gemtem00-RH.dat File Type: Comma-delimited ASCII File Name: gemtem00-NMIN.dat File Type: Comma-delimited ASCII File Name: gemtem00-NEP.dat File Type: Comma-delimited ASCII File Name: gemtem00-soilc.dat File Type: Comma-delimited ASCII File Name: gemtem00-vegc.dat File Type: Comma-delimited ASCII FILE FORMAT: year, model1, model2, model3 (models 1 = GEM, 2 = TEM reference, 3 = TEM fast soil C) NUMBER OF RECORDS: 181/file REFERENCE CITATIONS: Clein JS, Kwiatkowski BL, McGuire AD, Hobbie JE, Rastetter EB, Melillo JM, Kicklighter DW (2000) Modeling carbon responses of tundra ecosystems to historical and projected climate: A comparison of a fine- and coarse-scale ecosystem model for identification of process-based uncertainties. Global Change Biology, 6 (Suppl. 1), 127-140. Enting I, Wigley T, Heimann M (1994) Future emissions and concentrations of carbon dioxide: key ocean/atmosphere/land analyses. CSIRO Division of Atmospheric Research Technical Paper No. 31, 120pp. FAO-UNESCO (1971) Soil Map of the World, 1:5,000,000. Food and Agricultural Organization and United Nations Educational, Scientific and Cultural Organization, Paris, France. Hulme M (1995) A historical monthly precipitation data for global land areas from 1900 to 1994, gridded at 3.75 x 2.5 resolution. Constructed at climate research Unit, University of East Anglia, Norwich, UK. Jones PD (1994) Hemispheric surface air temperature variations: a reanalysis and an update to 1993. Journal of Climate, 7, 1794-1802. Leemans R, Cramer WP (1991) The IIASA database for mean monthly values of temperature, precipitation, and cloudiness on a global terrestrial grid. IIASA RR-91-18, Laxenburg, Austria. Legates DR, Willmott CJ (1990a) Mean seasonal and spatial variability in global surface temperature. Theoretical Applications in Climatology, 41, 11-21. Legates DR, Willmott CJ (1990b) Mean seasonal and spatial variability in gauge-corrected, global-precipitation. International Journal of Climatology, 10, 11-127. McGuire AD, Clein JS, Melillo JM, Kicklighter, DW, Meier RA, Vorosmarty CJ Serreze MC (2000) Modeling carbon responses of tundra ecosystems to historical and projected climate: sensitivity of pan-Arctic carbon storage to temporal and spatial variation in climate. Global Change Biology, 6 (Suppl. 1), 141-159. McGuire AD, Melillo JM, Joyce LA, Kicklighter DW, Grace AL, Moore B III, Vorosmarty CJ (1992) Interactions between carbon and nitrogen dynamics in estimating net primary productivity for potential vegetation in North America. Global Biogeochemical Cycles, 6, 101-124. McGuire AD, Melillo JM, Randerson JT, et al. (1999) Modeling the effects of snowpack on heterotrophic respiration across northern temperate and high latitude regions: Comparison with measurements of atmospheric carbon dioxide in high latitudes. Biogeochemistry, 48, 91-114. NCAR/Navy (1984) Global 10-minute elevation data. Digital tape available through National Oceanic and Atmospheric Administration, National Geophysical Data Center, Boulder, Colorado. Rastetter, EB, Ryan MG, Shaver GR, Melillo JM, Nadelhoffer KJ, Hobbie JE, Aber JD (1991) A general biogeochemical model describing the responses of the C and N cycles in terrestrial ecosystems to changes in CO2, climate, and N deposition, Tree Physiology, 9, 101-126. ACKNOWLEDGEMENTS: This research was supported by funds from the ARCSS Program of NSF as a Synthesis, Integration, and Modeling Study (SIMS; OPP-9614253).