09/03/2013

Combining Ground Station and Satellite Data for Better Estimates of CO2 Emissions

Summary

Scientists from Lawrence Berkeley National Laboratory present one of the first estimates of the global distribution of CO₂ surface fluxes using total column CO₂ measurements retrieved by the SRON-KIT RemoTeC algorithm from the Greenhouse gases Observing SATellite (GOSAT). The international research team used a series of calculations to combine data from the satellite over an 18-month period with nearly 17,000 surface-level observations from 132 locations during the same period. The team used this data to estimate the CO₂ sources and sinks around the world. Their global scale results compared favorably to independent estimates made by government agencies, while at regional scales some differences raised questions for future exploration. The study shows that assimilating the bias corrected satellite data on top of surface CO₂ data reduces the estimated global CO₂ land sink and shifts the net terrestrial carbon uptake from the tropics to the extratropics. It is concluded that while GOSAT total column CO₂ provides useful constraints for source-sink inversions, small spatiotemporal biases – beyond what can be detected using current validation techniques – have serious consequences for optimized fluxes, even aggregated over continental scales.

References

Basu, S., S. Guerlet, A. Butz, S. Houweling, O. Hasekamp, I. Aben, P. Krummel, P. Steele, R. Langenfeld, M. Torn, S. Biraud, B. Stephens, A. Andrews, and D. Worthy. 2013. “Global CO₂ Fluxes Estimated from GOSAT Retrievals of Total Column CO₂,” Atmospheric Chemistry and Physics 13, 8695-717. DOI:10.5194/acp-13-8695-2013.