TY - JOUR
T1 - Arctic Ocean CO2 uptake
T2 - An improved multiyear estimate of the air-sea CO2 flux incorporating chlorophyll a concentrations
AU - Yasunaka, Sayaka
AU - Siswanto, Eko
AU - Olsen, Are
AU - Hoppema, Mario
AU - Watanabe, Eiji
AU - Fransson, Agneta
AU - Chierici, Melissa
AU - Murata, Akihiko
AU - Lauvset, Siv K.
AU - Wanninkhof, Rik
AU - Takahashi, Taro
AU - Kosugi, Naohiro
AU - Omar, Abdirahman M.
AU - Van Heuven, Steven
AU - Mathis, Jeremy T.
N1 - Funding Information:
Acknowledgements. We thank the many researchers and funding agencies responsible for the collection of data and quality control for their contributions to SOCAT and GLODAPv2. We are grateful for the use of the CO2SYS program obtained from the Ocean Carbon Data System of NOAA National Centers for Environmental Information (https://www.nodc.noaa.gov/ocads/oceans/CO2SYS/co2rprt.html), and SOM Toolbox version 2 developed by the Laboratory of Information and Computer Science at Helsinki University of Technology (http://www.cis.hut.fi/projects/somtoolbox). We thank ACRI-ST, France, for developing, validating, and distributing the GlobColour data used in this work. This work was financially supported by the Arctic Challenge for Sustainability (ArCS) Project funded by the Ministry of Education, Culture, Sports, Science and Technology, Japan. Are Olsen was supported by grants from the Norwegian Research Council (Subpolar North Atlantic Climate States (SNACS) 229752 and the Norwegian component of the Integrated Carbon Observation System (ICOS-Norway 245927). Mario Hoppema was partly supported by the German Federal Ministry of Education and Research (grant no. 01LK1224I; ICOS-D). Siv K. Lauvset acknowledges support from the Norwegian Research Council (VENTILATE, 229791) and the EU H2020 project AtlantOS (grant agreement no. 633211). Rik Wanninkhof and Taro Takahashi acknowledge support from the Office of Oceanic and Atmospheric Research (OAR) of NOAA, including resources from the Ocean Observation and Monitoring Division of the Climate Program Office (fund reference 100007298). We thank two anonymous reviewers for providing helpful comments.
Publisher Copyright:
© Author(s) 2018.
PY - 2018/3/22
Y1 - 2018/3/22
N2 - We estimated monthly air-sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60° N from 1997 to 2014. This was done by mapping partial pressure of CO2 in the surface water (pCO2w) using a self-organizing map (SOM) technique incorporating chlorophyll a concentration (Chl a), sea surface temperature, sea surface salinity, sea ice concentration, atmospheric CO2 mixing ratio, and geographical position. We applied new algorithms for extracting Chl a from satellite remote sensing reflectance with close examination of uncertainty of the obtained Chl a values. The overall relationship between pCO2w and Chl a was negative, whereas the relationship varied among seasons and regions. The addition of Chl a as a parameter in the SOM process enabled us to improve the estimate of pCO2w, particularly via better representation of its decline in spring, which resulted from biologically mediated pCO2w reduction. As a result of the inclusion of Chl a, the uncertainty in the CO2 flux estimate was reduced, with a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tgyr-1. Seasonal to interannual variation in the CO2 influx was also calculated.
AB - We estimated monthly air-sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60° N from 1997 to 2014. This was done by mapping partial pressure of CO2 in the surface water (pCO2w) using a self-organizing map (SOM) technique incorporating chlorophyll a concentration (Chl a), sea surface temperature, sea surface salinity, sea ice concentration, atmospheric CO2 mixing ratio, and geographical position. We applied new algorithms for extracting Chl a from satellite remote sensing reflectance with close examination of uncertainty of the obtained Chl a values. The overall relationship between pCO2w and Chl a was negative, whereas the relationship varied among seasons and regions. The addition of Chl a as a parameter in the SOM process enabled us to improve the estimate of pCO2w, particularly via better representation of its decline in spring, which resulted from biologically mediated pCO2w reduction. As a result of the inclusion of Chl a, the uncertainty in the CO2 flux estimate was reduced, with a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tgyr-1. Seasonal to interannual variation in the CO2 influx was also calculated.
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U2 - 10.5194/bg-15-1643-2018
DO - 10.5194/bg-15-1643-2018
M3 - Article
AN - SCOPUS:85044305510
VL - 15
SP - 1643
EP - 1661
JO - Biogeosciences
JF - Biogeosciences
SN - 1726-4170
IS - 6
ER -