NASA/Ames Global Emissions Data Set (GLEMIS)
"NASA-CASA data sets include global maps for predicted fluxes of soil nitrogen gases (N2O and NO), methane (CH4), and carbon monoxide (CO), plus predictions of net primary production (NPP) and carbon storage in leaf, wood, root, litter, and surface soil pools. Others data sets will follow. The documentation text files called 'README_glemis' provides necessary downloading information (formats, references, methods, etc.) for the map files. All global data sets (except those for carbon storage) contain 12 monthly files, gridded with each cell representing 1 degree or 0.5 degree of latitude-longitude."