POTENTIAL GROSS PRIMARY PRODUCTIVITY OF TERRESTRIAL VEGETATION FROM 1982-1990

Monthly mean global green leaf area and photosynthetically active radiation estimated from observations made from several geostationary and polar orbiting satellites were used to estimate potential, (i.e., unstressed) gross primary productivity of terrestrial vegetation from 1982 to 1990. Mean annual gross primary productivity was estimated to be about 179.9 +/- 1.6 Pg C (1 Pg = 10(15) g). Grasses and xerophgtic vegetation on all continents exhibited high interannual variability. The evolution of monthly gross primary productivity anomalies was similar to atmospheric CO2 growth rate during 1982-1990. This was observed both globally and for the 30 degrees - 90 degrees N latitudional band, but not at other latitudes. From this, we may conclude that total ecosystem respiration and GPP respond similarly but disproportionately to climate: such that the difference between the two resembles the opposite of the observed atmospheric CO2 growth rate.