INTER-ANNUAL VARIABILITY OF NET ECOSYSTEM PRODUCTIVITY OVER INDIA

The net ecosystem productivity (NEP) is the estimates of net carbon exchanges between the vegetation-soil system and the atmosphere. Estimates of NEP could play important role in defining a terrestrial ecosystem as a net source and sink of atmospheric CO2. We model monthly NEP over India for past 26 years (1981-2006) by incorporating satellite observations of vegetation index together with other climatic parameters in to efficiency based terrestrial ecosystem model. Results depict large spatial and temporal variability of NEP over India. NEP climatology over India showed that this region sequestered annually 9.4 Tg C (at the rate of 2.54 gC m(-2)) and hence appeared to be a net sink of atmospheric CO2. Strength of the CO2 sequestration over the country has been increased during the study period with average linear growth rate of 1.8 TgC yr(-2).