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 descr ibed. GLO-PEM is the first attempt to model both global net and gross primary production using the production efficiency approach and is uni que in that it uses satellite data to measure both absorption of photo synthetically active radiation (APAR) and also the environmental varia bles that affect the utilization of APAR in primary production. The us e of satellite measurements gives global, repetitive, spatially contig uous and time specific observations of the actual vegetation. GLO-PEM is based on physiological principles, in particular the amount of carb on fixed per unit absorbed photosynthetically active radiation (epsilo n) is modelled rather than fitted using field observations.