Conference proceeding
Relationship of photosynthesis to atmospheric carbonyl sulfide for the North American growing season
Proceedings of the American Geophysical Union 2007 Fall Meeting
01/01/2007
Abstract
Projected changes in climate may reduce the uptake of atmospheric CO2 by terrestrial plants, creating a positive carbon-climate feedback. Our understanding of this feedback is primarily based on global photosynthesis models that were derived from leaf-scale models. It is difficult to validate photosynthesis models with atmospheric CO2 measurements because air depleted of CO2 by photosynthesis mixes with air enriched in CO2 by respiration. It was recently hypothesized that an independent assessment of photosynthesis models could be developed using atmospheric carbonyl sulfide (COS) which is closely related to photosynthesis by COS plant uptake but only has small terrestrial ecosystem sources. Here we report a COS model-observation analysis that is supportive of modeled photosynthesis estimates for the North American growing season. We compared airborne measurements with an atmospheric model driven by COS plant uptake, soil sinks, ocean sources, and anthropogenic sources. The COS plant uptake was calculated by scaling modeled photosynthesis by the plant chamber-derived ratio of photosynthesis to COS plant uptake. Observed and simulated COS concentrations along the flightpaths showed remarkable agreement, both indicating a 13 percent tropospheric drawdown. Modeled COS concentrations were dominated by plant uptake, unlike previous COS models that did not account for the COS-photosynthesis relationship. The model-observation agreement for this plant dominated system corroborates the modeled photosynthesis estimates and the extrapolation of the photosynthesis-COS relationship from plant chamber experiments to our regional atmospheric analysis. We anticipate that our model- observation analysis will be a starting point for using the global observation network9 in a data assimilation framework to constrain climate-photosynthesis sensitivities.
Details
- Title: Subtitle
- Relationship of photosynthesis to atmospheric carbonyl sulfide for the North American growing season
- Creators
- J E CampbellG R CarmichaelT ChaiJ MoenM Mena-CarrascoY TangD R BlakeN J BlakeS A VayS A MontzkaG J CollatzJ A BerryJ L SchnoorC O Stanier
- Resource Type
- Conference proceeding
- Publication Details
- Proceedings of the American Geophysical Union 2007 Fall Meeting
- Language
- English
- Date published
- 01/01/2007
- Academic Unit
- Nursing; Occupational and Environmental Health; Chemical and Biochemical Engineering; Civil and Environmental Engineering; Center for Global & Regional Environmental Research
- Record Identifier
- 9983997419402771
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