Net Primary Productivity by photosynthesis on land

Value 54.9 Pg C/Yr Range: 39.9-80.5 Pg C/Yr
Organism Biosphere
Reference W. Cramer et al, Comparing global models of terrestrial net primary productivity (NPP): overview and key results, Global change biology (1999) 5 (suppl. 1) 1-15
Method Seventeen global models of terrestrial biogeochemistry were compared with respect to annual and seasonal fluxes of net primary productivity (NPP) for the land biosphere. The comparison, sponsored by IGBP-GAIM/DIS/GCTE, used standardized input variables wherever possible and was carried out through two international workshops and over the internet. The models differed widely in complexity and original purpose, but could be grouped in three major categories: satellite-based models that use data from the NOAA/AVHRR sensor as their major input stream (CASA, GLO-PEM, SDBM, PLAI 0.1, SILVAN 2.2, and TEM 4.0), and models that simulate both vegetation structure and carbon fluxes (BIOME3, DOLY and HYBRID 3.0). The simulations resulted in a range of total NPP values (44.4-66.3 Pg C/Yr), after removal of two outliers (which produced extreme results as artefacts due to the comparison). Note that value above includes the two outliers, 80.5 Pg C/Yr (TURC), and 39.9 Pg C/Yr (HYBRID)
Comments The models predict net annual production on land between 39.9 and 80.5 Pg C with a mean of 54.9 Pg C (Table 5). P= peta-, an SI prefix denoting a factor of 10^15. See BNID 103500,102934 (both entries for terrestrial NPP in Carbon),100596 (terrestrial NPP in total dry weight). 102955 (seasonal terrestrial NPP), 100601 (various values in database link)
Entered by Uri M
ID 105063