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Data Archive for the PIK IGBP-GCTE DGVM Intercomparison Project

This archive documents all data that have been generated in connection with the "Intercomparison of Dynamic Global Vegetation Models" carried out under the auspices of the International Geosphere Biosphere Programme, core project Global Change and Terrestrial Ecosystems, at the Potsdam Institute for Climate Impact Research. The original results of this comparison are published in: Cramer W, Bondeau A, Woodward FI, Prentice IC, Betts RA, Brovkin V, Cox PM, Fisher V, Foley JA, Friend AD, Kucharik C, Lomas MR, Ramankutty N, Sitch S, Smith B, White A & Young-Molling C 2001 Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models. Global Change Biology7(4):357-373.All data may be downloaded from this server. Please ensure that proper reference is being made to the individual modelling teams.

Requests for further information should be made to

Wolfgang Cramer
Potsdam Institute for Climate Impact Research
PO Box 60 12 03, D-144 12 Potsdam, Germany
Tel.: +49-331-2882521, Fax: +49-331-2882600
E-mail: Wolfgang.Cramer -at- pik-potsdam.de

Input data used for DGVM calculations

http://www.pik-potsdam.de/data/dgvm_gcb_2000/input

These data are derived from the HadCM2-SUL climate model but have received additional processing for the purposes of the DGVM model comparison. The basics of this processing are described in the paper. The data should NOT be considered a realistic climate data set for modern climate.

Monthly input climate data, derived from climate model output

variable code
Minimum temperature (°C) tmin
Maximum temperature (°C) tmax
Precipitation (mm) prec
Sunshine (% hours of possible) suns
Relative humidity (%) humi
Total incoming short wave radiation (W m-2) swrd

For each of these variables, there are

31 annual data files for the "spinup years" (named "1830" "1860" for convenience they are to be considered scenario data for a stable preindustrial climate)   239 annual data files for the years with processed output from the transient climate model simulation (named "1861" "2199" this is based on observed or estimated CO2 concentrations as external forcing of the model, the data reflect therefore not the actual year-by-year climate fluctuations)   100 annual data files for the years of the abrupt stabilisation scenario based on simulated conditions in 2099 (named "2100" "2199")

File names:

e.g. "prec1861.dat" (precipitation for 1861)

File format:

1631 lines for 1631 grid cells   12 columns with the monthly values The south-west coordinates of the 1631 grid cells are provided in the file landpix.dat

The 370 annual data files for each climate variable are tar-archived and compressed (names see table above)

All variables (to the exception of humi) are constructed by first calculating climate model anomalies in relation to the monthly long term means of the simulated years 1931-60. These anomalies were then applied to an observed climatology for 1931-60. The result therefore retains the spatial pattern of average observed climate in combination with the temporal dynamics of the climate model.

The annual CO2 concentrations (ppm) from historical observations and for a future scenario, from 1861 to 2099, are provided in the file co2sim.dat.

Output data from the six participating DGVMs:

File locations:

http://www.pik-potsdam.de/data/dgvm_gcb_2000/output/hybrid

http://www.pik-potsdam.de/data/dgvm_gcb_2000/output/ibis

http://www.pik-potsdam.de/data/dgvm_gcb_2000/output/lpj

http://www.pik-potsdam.de/data/dgvm_gcb_2000/output/sdgvm

http://www.pik-potsdam.de/data/dgvm_gcb_2000/output/triffid

http://www.pik-potsdam.de/data/dgvm_gcb_2000/output/vecode

Variables:

All variables are listed in separate files. Biomass, NPP and LAI are given separately for each plant functional type (pft), using the pfts: C3 grass ("3"), C4 grass ("4"), deciduous trees ("d"), evergreen trees ("e"). biomass ("bio", in kg C m-2)

net primary productivity ("npp", in kg C m-2 y-1)

leaf area index ("lai")

soil carbon ("soil", in kg C m-2)

runoff ("runo", in m y-1)

Experiments:

climate change only ("T")

CO2 increase only ("C")

CO2 increase & climate change ("CT")

File names:

e.g. ibio3_C.dat: 'i' for model IBIS; 'bio3' for C3 grass biomass; 'C' for experiment C

File format:

ASCII

1631 lines for 1631 grid cells (ice-free land cells in the HadCM2 climate model, the size of these cells is 3.75 degrees in longitudinal and 2.5 degrees in latitudinal direction)

Each line contains 341 space-delimited data columns:

longitude of SW corner (degrees, with decimals)
latitude of SW corner (degrees, with decimals)
output data for the 339 years of the simulation (1861-2199)

Figures

http://www.pik-potsdam.de/data/dgvm_gcb_2000/figs this directory contains ps and eps files of figures 2-3-4-5-6-7-8

Processed DGVM Output for the figures

(The technical description of these data is located at the top of the files)

Vegetation classification for figure 2:

http://www.pik-potsdam.de/data/dgvm_gcb_2000/figs/processed/clafig2.dat

Zonal NEP for figure 6:

http://www.pik-potsdam.de/data/dgvm_gcb_2000/figs/processed/nepzonalfig6.dat
(last updated on 4.1.07)

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link to Wolfgang Cramer's homepage
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