Space-based measurements of CO2: past, present and future

Space-based measurements of atmospheric carbon dioxide are believed to have the potential to revolutionize our understanding of carbon sources and sinks over  land and ocean regions worldwide.  Since the first dedicated greenhouse gas mission (the Greenhouse gases Observing SATellite or GOSAT) launched ten years ago, we’re now in a place with 4 such satellites in orbit and many more coming.   However, use of these data are challenging because of the incredibly tight accuracy, on the order of 0.1%, which are required to make significant progress and which have not yet been fully realized.

This broad talk will discuss the retrieval algorithms used to infer CO2 from the shortwave infrared measurements, the science currently being done with them, and what breakthroughs the future may hold as we improve the algorithms and launch new and more capable satellites. The Orbiting Carbon Observatory-2 (OCO-2) satellite launched in 2014 and has been a critical pathfinder for this emerging field.  The OCO-3 instrument, slated to be installed on the International Space Station this spring, is similar to OCO-2 but has important new capabilities, including the ability to over one hundred cities each day and will have full diurnal coverage.  Finally, the GeoCarb instrument will be the first such geostationary instrument and will measure methane and carbon monoxide as well as CO2.  These new satellites plus a slew of others planned by the international community herald a new era of understanding and monitor of the earth’s carbon cycle, and human-induced changes to it.