Estimation of carbon transfer coefficients using Duke Forest free-air CO₂ enrichment data

A compartmental carbon model is presented in which there are parameters quantifying the transfer between various carbon pools. These parameters are estimated using two CO₂ data sets (elevated and ambient) from the Duke Forest FACE data set. A quadratic objective criterion is used to compare closeness of fit of system output CO₂ flux to the observed CO₂ flux data. Adjoint equations are developed based on the system of difference equations approximating the solution of the model equations, the data, and the criterion. Parameter estimation algorithms are developed using minimization techniques. It is found that the estimated parameters obtained using the two different data sets agree closely.