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 ...
[Source: NASA/GISS, http://data.giss.nasa.gov/ch4_fung/ ]
Surface Exchange of Methane (Fung et al. 1991)
This page offers access to a number of datasets which describe the exchange of methane between ...