Estimating daytime ecosystem respiration from eddy-flux data.

To understand what governs the patterns of net ecosystem exchange of CO₂, an understanding of factors influencing the component fluxes, ecosystem respiration and gross primary production is needed. In the present paper, we introduce an alternative method for estimating daytime ecosystem respiration based on whole ecosystem fluxes from a linear regression of photosynthetic photon flux density data vs. daytime net ecosystem exchange data at forest ecosystem level. This method is based on the principles of the Kok-method applied at leaf level for estimating daytime respiration. We demonstrate the method with field data and provide a discussion of the limitations of the method.