The satellite gives gas concentration in the atmosphere. It’s a second step, called “flux inversion,” to backtrack from the concentration to emission, or “flux”

The satellite gives gas concentration in the atmosphere. It’s a second step, called “flux inversion,” to backtrack from the concentration to emission, or “flux” in the jargon. You need to have wind information (“advection”) to do this, of course. There is a scientific literature going back decades on these approaches.