I read this variable from individual site data files. Meanwhile I also change the direction of nee (the positive means land sinks co2 from atmosphere now) and convert the unit from umol_m-2_s-1 to Kg C m-2 s-1. Then organized those sites with valid data, and save the data in NetCDF format by each month and each year.
Temporal resolution:
monthly
General information:
This product was derived from site level estimates of GPP and TER from FLUXNET eddy covariance stations.