Global CO2 fluxes estimated from GOSAT retrievals of total column CO2

• Verfasst von: Basu, Sourish [VerfasserIn]
• Verfasst von: Butz, André [VerfasserIn]
• Titel: Global CO2 fluxes estimated from GOSAT retrievals of total column CO2
• Verf.angabe: S. Basu, S. Guerlet, A. Butz, S. Houweling, O. Hasekamp, I. Aben, P. Krummel, P. Steele, R. Langenfelds, M. Torn, S. Biraud, B. Stephens, A. Andrews, and D. Worthy
• Umfang: 23 S.
• Fussnoten: Im Titel ist die "2" jeweils tiefgestellt ; Gesehen am 15.01.2019
• Titel Quelle: Enthalten in: Atmospheric chemistry and physics
• Jahr Quelle: 2013
• Band/Heft Quelle: 13(2013), 17, S. 8695-8717
• ISSN Quelle: 1680-7324
• DOI: doi:10.5194/acp-13-8695-2013
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1586235877

Abstract

<p><strong>Abstract.</strong> We 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). We derive optimized fluxes from June 2009 to December 2010. We estimate fluxes from surface CO₂ measurements to use as baselines for comparing GOSAT data-derived fluxes. Assimilating only GOSAT data, we can reproduce the observed CO₂ time series at surface and TCCON sites in the tropics and the northern extra-tropics. In contrast, in the southern extra-tropics GOSAT X_CO₂ leads to enhanced seasonal cycle amplitudes compared to independent measurements, and we identify it as the result of a land-sea bias in our GOSAT X_CO₂ retrievals. A bias correction in the form of a global offset between GOSAT land and sea pixels in a joint inversion of satellite and surface measurements of CO₂ yields plausible global flux estimates which are more tightly constrained than in an inversion using surface CO₂ data alone. We show that assimilating the bias-corrected GOSAT data on top of surface CO₂ data (a) reduces the estimated global land sink of CO₂, and (b) shifts the terrestrial net uptake of carbon from the tropics to the extra-tropics. It is concluded that while GOSAT total column CO₂ provide 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.</p>