Global primary production: A remote sensing approach

A new model of global primary production (GLObal Production Efficiency Model, GLO-PEM), based on the production efficiency concept, is described. GLO-PEM is the first attempt to model both global net and gross primary production using the production efficiency approach and is unique in that it uses satellite data to measure both absorption of photosynthetically active radiation (APAR) and also the environmental variables that affect the utilization of APAR in primary production. The use of satellite measurements gives global, repetitive, spatially contiguous and time specific observations of the actual vegetation. GLO-PEM is based on physiological principles, in particular the amount of carbon fixed per unit absorbed photosynthetically active radiation (epsilon) is modelled rather than fitted using field observations.