What is an operation?

An operation is a process within the FLINT that moves carbon stock between pools. Operations can reflect ongoing natural processes, such as growth, or specific events, natural or human-induced; for example, a harvest moves plant material to products and debris pools, wildfire moves plant material to debris and atmosphere pools. The amount of stock moved during an operation is called a ‘flux.’ Operations allows the FLINT to track changes in carbon stock through time, including fluxes into and out of pools.

How are operations used in FLINT?

FLINT uses operations to update simulation units values and record flux values in a flux table. For example, an operation reflecting plant growth can be applied to aboveground biomass pools to estimate the growth flux. FLINT has been designed to ensure the conservation of mass and area throughout the calculation process. This means that FLINT will only transfer carbon stock from one pool to another, ensuring the system is balanced so that the sum of the fluxes is equal to the sum of the stock changes.

Suppose there is a violation in this principle, for example, that the system is unbalanced. In that case, FLINT will report this violation and take the appropriate action (e.g., flag the outputs as unreliable). FLINT tracks each operation and the resulting fluxes and depending on which pools the flux relates to, it is classified differently in the flux table and the resulting carbon stock tables. For example, the output will be ‘aboveground biomass.’ We can then use the resulting information to calculate different characteristics of the Simulation Unit. For example, by summing all stock change in the aboveground, belowground biomass, we can calculate net litter turnover, the Net Primary Production (NPP).

Similarly, all fluxes from dead organic matter and soil C pools to the atmosphere pools resulting from decay processes are considered heterotrophic respiration (Rh). By subtracting Rh from NPP, We can calculate net Ecosystem Productivity (NEP).

While fluxes from any pool to the atmosphere related to disturbances also need to be tracked by disturbance type to account for the impacts. NEP minus losses from disturbances equal Net Biome Production (NBP). Operations could be developed into FLINT to provide the output of such calculations (e.g., NPP, NEP, and NBP). However, by only providing the input values, there is increased system transparency, which in turn increases integrity.

In addition to moving carbon stocks between different pools, operations are used in the Unit Controller in FLINT to manage data on different temporal scales to ensure comparable outputs are produced. The outputs can be reported at varying temporal scales (See Unit Controller and Temporal Distribution).