Dynamic vegetation: Yes. At each time (monthly) step tree and grass growth is calculated in terms of NPP, and live carbon may be lost through fire. In each gridcell tree and grass lifeforms compete for light and water. At the end of each year, the gridcell is reclassified into one of many PFTs, which in turn affect fire occurrence and effects.
Nitrogen limitation: Not simulated.
Co2 effects: For both simulated trees and grasses, total potential production is enhanced by a coefficient of atmospheric CO2 concentration, which equals 1 at 350 ppm and 1.25
when CO2 concentration reaches 700 ppm. Effects are linear between those two points. (Total potential production may be further reduced by climate and site conditions before NPP is derived.) Similarly, potential transpiration rate equals 1.0 at 350 ppm and is reduced to 0.75 when CO2 concentration reaches 700 ppm.
Light interception: Only the effect of tree shading grass is simulated, using Beers law, which reduced grass production.
Phenology: Leaf phenology (deciduous vs. needleleaf, and evergreen vs. broadleaf) is estimated as a function of long-term temperature and precipitation. Seasonal leaf phenology is not explicitly simulated, and is an emergent effect as climatic conditions are sufficient temperature and moisture allow NPP.
Water stress: Reductions in available soil water and precipitation, as well as increases in PET, reduces NPP.
Heat stress: NPP is reduced for trees when monthly temperature reaches 30 degC for needleleaf trees; 35 degC for deciduous broadleaf trees; 45 for evergreen broadleaf trees; 32 degC for C3 grass; and 45 degC for C4 grass.
Evapo-transpiration approach: PET is calculated as a function of average monthly maximum and minimum temperatures from the equations of Linacre (1977). Snow is evaporated as a function of PET. Bare soil water evaporation and interception by the canopy are functions of aboveground biomass, rainfall, and PET. Water is transpired from each soil layer as a function of live biomass, ensuring that total evapotranspiration does not exceed PET.
Root distribution over depth: Not explicitly simulated.
Closed energy balance: Not simulated.
Coupling/feedback between soil moisture and surface temperature: Not simulated.
Latent heat: Not simulated.
Sensible heat: Not simulated.
How do you compute soil organic carbon during land use (do you mix the previous pft soc into agricultural soc)?: Not simulated.
Do you separate soil organic carbon in pasture from natural grass?: No.
Do you harvest npp of crops? do you including grazing? how does harvested npp decay?: No.
How do you to treat biofuel npp and biofuel harvest?: No.
Does non-harvested crop npp go to litter in your output?: No.
