(1) MODEL AND VERSION: GTEC 2.0
Full model name: Global Terrestrial Ecosystem Carbon (GTEC) Version 2.0
Host institution: Oak Ridge National Laboratory
References:
Post, W. M., King, A. W., and S. D. Wullschleger 1996. Soil organic matter models and global estimates of soil organic carbon. pp. 201-222. IN (P. Smith, J. Smith and D. Powlson, eds.) Evaluation of Soil Organic Matter Models Using Existing Long-Term Datasets. Springer-Verlag, Berlin.
King, A. W., W. M. Post and S. D. Wullschleger. 1997. The potential response of terrestrial carbon storage to changes in climate and atmospheric CO2. Climatic Change 35:199-227.
Post, W. M., A. W. King, and S. D. Wullschleger 1997. Historical variations in terrestrial biospheric carbon storage. Global Biogeochemical Cycles 11:99--109.
King, A. W., S. D. Wullschleger and W, M. Post. Seasonal biosphere-atmosphere CO2 exchange and terrestrial ecosystem carbon storage: mechanism, extrapolation, and implications. Paper presented at the 5th International Carbon Dioxide Conference, 8-12 September 1997, Cairns, Queensland, Australia.
(2) MODEL TYPE:
Ecosystem
(3) PRIMARY MODEL PURPOSE:
Understanding role of terrestrial ecosystems in the global carbon cycle
(4) MODELING APPROACH:
Mechanistic, process-based simulation of simultaneous soil-plant-atmosphere carbon and water fluxes and resulting changes in plant and soil carbon reservoirs using difference equations.
(5) RESOLUTION:
Spatial: 1 degree latitude X 1 degree longitude
Temporal: hourly and daily
(6) SPATIAL AND TEMPORAL SCALES AT WHICH MODEL RESULTS SHOULD BE CONSIDERED:
Spatial: global and regional
Temporal: daily, monthly, annual over periods of up to several hundred years
(7) PROCESSES AND PROCESS COMPONENTS SIMULATED:
Carbon: GPP, NPP, and NEP
Water: transpiration and evapotranspiration
a) soils: layered soil, piston flow
b) energy balance: latent heat, actual evapotranspiration
c) snow: not simulated
d) order of water balance: canopy interception and evaporation, throughfall, infiltration, transpiration
Nitrogen: nitrogen dynamics are not simulated; assumes an open N cycle
(8) SIMULATED RESERVOIRS:
Carbon
a)vegetation: leaves, stem, coarse roots, fine roots
b) litter: decomposable and recalcitrant litter
c) SOC: humus, microbial biomass, and inert organic matter
Nitrogen
a) vegetation: same as for carbon
b) litter: not represented
c) SOC: not represented
(9) CALIBRATION VARIABLES AND METHOD:
model is calibrated against observations of leaf and ecosystem (stand) scale carbon and water flux through a non-automated iterative process of model verification, validation, and revision.
(10) SCALING OF PROCESSES TO THE GRID CELL:
assumes homogeneous vegetation and soils for each grid cell, and multiplies results from a point simulation at the centroid of the cell by the area of the cell
(11) DISTURBANCES:
disturbance is not simulated
(12) VEGETATION I/O:
uses actual (but static) vegetation
(13) INPUT DRIVERS FOR MODEL INITIALIZATION:
daily or monthly climate (shortwave irradiance [or clouds], air temperature, relative humidity, precipitation), daily or monthly leaf area index, vegetation type, soil type.