COS-derived GPP relationships with temperature and light help explain high-latitude atmospheric CO2 seasonal cycle amplification

Hu, Lei, Montzka, Stephen A., Kaushik, Aleya, Andrews, Arlyn E., Sweeney, Colm, Miller, John, Baker, Ian T., Denning, Scott, Campbell, Elliott, Shiga, Yoichi P., Tans, Pieter, Siso, M. Carolina, Crotwell, Molly, Mckain, Kathryn, Thoning, Kirk, Hall, Bradley, Vimont, Isaac, Elkins, James W., Whelan, Mary E. and Suntharalingam, Parvadha (2021) COS-derived GPP relationships with temperature and light help explain high-latitude atmospheric CO2 seasonal cycle amplification. Proceedings of the National Academy of Sciences of the United States of America (PNAS), 118 (33). ISSN 0027-8424

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Abstract

In the Arctic and Boreal region (ABR) where warming is especially pronounced, the increase of gross primary production (GPP) has been suggested as an important driver for the increase of the atmospheric CO 2 seasonal cycle amplitude (SCA). However, the role of GPP relative to changes in ecosystem respiration (ER) remains unclear, largely due to our inability to quantify these gross fluxes on regional scales. Here, we use atmospheric carbonyl sulfide (COS) measurements to provide observation-based estimates of GPP over the North American ABR. Our annual GPP estimate is 3.6 (2.4 to 5.5) PgC · y −1 between 2009 and 2013, the uncertainty of which is smaller than the range of GPP estimated from terrestrial ecosystem models (1.5 to 9.8 PgC · y −1). Our COS-derived monthly GPP shows significant correlations in space and time with satellite-based GPP proxies, solar-induced chlorophyll fluorescence, and near-infrared reflectance of vegetation. Furthermore, the derived monthly GPP displays two different linear relationships with soil temperature in spring versus autumn, whereas the relationship between monthly ER and soil temperature is best described by a single quadratic relationship throughout the year. In spring to midsummer, when GPP is most strongly correlated with soil temperature, our results suggest the warming-induced increases of GPP likely exceeded the increases of ER over the past four decades. In autumn, however, increases of ER were likely greater than GPP due to light limitations on GPP, thereby enhancing autumn net carbon emissions. Both effects have likely contributed to the atmospheric CO 2 SCA amplification observed in the ABR.

Item Type: Article
Additional Information: Acknowledgments: This work is funded by the NASA Terrestrial Ecology Program (80NSSC19M0105). We thank our retired colleague B. Miller for his contribution to the North American COS measurements. We thank A. Jacobson and K. Schuldt for preparing CT2017s assimilated 4D CO2 mole fraction field. Data Availability: CarbonTracker CT2017 results can be downloaded from the website at http:// carbontracker.noaa.gov. We thank J. Kofler, J. Higgs, T. Newberger, S. Wolter, D. Neff, E. Moglia, and others for their work associated with flask-air sampling.
Uncontrolled Keywords: arctic and boreal ecosystems,co seasonal cycle amplitude,carbonyl sulfide,climate change,gross primary production,general ,/dk/atira/pure/subjectarea/asjc/1000
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: LivePure Connector
Date Deposited: 21 Oct 2021 01:25
Last Modified: 21 Oct 2021 01:25
URI: https://ueaeprints.uea.ac.uk/id/eprint/81843
DOI: 10.1073/pnas.2103423118

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