Canopy processes in Terrestrial Ecosystem Models
The global carbon cycle is a complex symphony of fluxes of carbon between various sources and sinks in the atmosphere, oceans, biosphere and soil. Measuring these fluxes experimentally is possible, but only over small areas so global flux estimations require numerical approaches. The UK Met Office brought its considerable expertise in weather and climate prediction to CAMELS, an R&D project designed to resolve CO2 savings from changes in land management practice. To achieve this objective, it was necessary to advance the state-of-the-art in Terrestrial Ecosystem Modelling (TEM). Previous TEM studies identified weaknesses with canopy parameterisations resulting in over-prediction of the Net Ecosystem Productivity (NEP). The Met Office examined alternatives to the traditional application of the Penman-Monteith energy combination equation at the leaf level. Specifically, more detailed descriptions of the canopy structure and the physical processes affecting the diurnal NEP cycle were assessed. Through this work, the CAMELS consortium hopes to increase the accuracy of the Global Circulation Models (GCMs) with which the TEMS are coupled. This in turn should improve confidence in global carbon cycle calculations and, consequently, in studies of the possible effects on the climate system.