TransCom 3 Level 1 data archive has been published! The complete citation and link are as follows:

Gurney, K. R., and A. S. Denning. 2008. TransCom 3: Annual Mean CO2 Flux Estimates from Atmospheric Inversions (Level 1). Data set. Available on-line [http://daac.ornl.gov/] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/895.