Dynamic vegetation: no
Nitrogen limitation: yes.
In addition to the relatively rapid cycling of nitrogen within the plant – litter – soil organic matter system, CLM also represents several slow processes which couple the internal nitrogen cycle to external sources and sinks. Inputs of new mineral nitrogen are from atmospheric deposition and biological nitrogen fixation. Losses of mineral nitrogen are due to nitrification, denitrification, leaching, and losses in fire. While the short-term dynamics of nitrogen limitation depend on the behavior of the internal nitrogen cycle, establishment of total ecosystem nitrogen stocks depends on the balance between sources and sinks in the external nitrogen cycle.
Co2 effects: yes
Light interception: yes
Phenology: yes, dynamic.
The CLM phenology model consists of several algorithms controlling the transfer of stored carbon and nitrogen out of storage pools for the display of new growth and into litter pools for losses of displayed growth. PFTs are classified into three distinct phenological types that are represented by separate algorithms: an evergreen type, for
which some fraction of annual leaf growth persists in the displayed pool for longer than one year; a seasonal-deciduous type with a single growing season per year, controlled mainly by temperature and daylength; and a stress-deciduous type with the potential for multiple growing seasons per year, controlled by temperature and soil moisture conditions.
Water stress: yes.
soil water influences stomatal resistance directly by
multiplying the minimum conductance by a soil water stress function βt (which ranges from 0 to 1) and also indirectly through A n , as in (Sellers et al. 1996).
Heat stress: no
Evapo-transpiration approach: Monin-Obukhov similarity theory
Root distribution over depth: plant types differ in leaf and stem optical properties that determine reflection, transmittance, and absorption of solar radiation, root distribution parameters that control the uptake of water from the soil, aerodynamic parameters that determine resistance to heat, moisture, and momentum transfer, and photosynthetic parameters that determine stomatal resistance, photosynthesis, and transpiration.
Closed energy balance: Yes, checked every time step at the grid cell level
Coupling/feedback between soil moisture and surface temperature: yes
Latent heat: Monin-Obukhov similarity theory
Sensible heat: Monin-Obukhov similarity theory
How do you compute soil organic carbon during land use (do you mix the previous pft soc into agricultural soc)?: All PFTs (except irrigated crops) share one soil column, land cover maps are prescribed and constant during a simulation period (e.g. historical period). when transforming from 1860soc to 2005soc at the start of the historical period, initial conditions for the historical run are interpolated from the pre-industrial restart file.
Do you separate soil organic carbon in pasture from natural grass?: no, all PFTs (except irrigated crops) share one soil column.
Do you harvest npp of crops? do you including grazing? how does harvested npp decay?: Crops are harvested, grazng is not considered
How do you to treat biofuel npp and biofuel harvest?: not considered
Does non-harvested crop npp go to litter in your output?: "Harvest is assumed to occur as soon as the crop reaches aturity. When 2mTGDD reaches 100% of GDDmat or the number of days past planting reaches a crop-specific aximum (Table 20.1), then the crop is harvested. Harvest occurs in one time step using CN’s leaf offset algorithm. New variables track the flow of grain C and N to food and of live stem C and N to litter. Currently, food C and N are routed directly to litter using the labile, cellulose, and lignin fractions for leaves. The same fractions for leaves are used for the flow of live stem C and N to litter for corn, soybean, and temperate cereals. This is in contrast to the approach for unmanaged PFTs which puts live stem C and N to dead stems first, rather than to litter." (Oleson et al., 2013)
