@article{e6e6704a718042e586b7a2dd09adf373,
title = "Autonomous Biogeochemical Floats Detect Significant Carbon Dioxide Outgassing in the High-Latitude Southern Ocean",
abstract = "Although the Southern Ocean is thought to account for a significant portion of the contemporary oceanic uptake of carbon dioxide (CO2), flux estimates in this region are based on sparse observations that are strongly biased toward summer. Here we present new estimates of Southern Ocean air-sea CO2 fluxes calculated with measurements from biogeochemical profiling floats deployed by the Southern Ocean Carbon and Climate Observations and Modeling project during 2014–2017. Compared to ship-based CO2 flux estimates, the float-based fluxes find significantly stronger outgassing in the zone around Antarctica where carbon-rich deep waters upwell to the surface ocean. Although interannual variability contributes, this difference principally stems from the lack of autumn and winter ship-based observations in this high-latitude region. These results suggest that our current understanding of the distribution of oceanic CO2 sources and sinks may need revision and underscore the need for sustained year-round biogeochemical observations in the Southern Ocean.",
keywords = "SOCCOM, air-sea carbon flux",
author = "Gray, {Alison R.} and Johnson, {Kenneth S.} and Bushinsky, {Seth M.} and Riser, {Stephen C.} and Russell, {Joellen L.} and Talley, {Lynne D.} and Rik Wanninkhof and Williams, {Nancy L.} and Sarmiento, {Jorge Louis}",
note = "Funding Information: This work was sponsored by the U.S. National Science Foundation (NSF) through the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project under the PLR-1425989 to J. L. S., supplemented by National Aeronautics and Space Administration Award NNX14AP49G. Logistical support for SOCCOM in the Southern Ocean was provided by NSF through the U.S. Antarctic Program and the U.S. GO-SHIP program, Australia{\textquoteright}s Commonwealth Scientific and Industrial Research Organisation (CSIRO), and Germany{\textquoteright}s Alfred Wegener Institute (AWI). Additionally, we acknowledge support from U.S. Argo through National Oceanic and Atmospheric Administration (NOAA) grant NA17RJ1232 to the University of Washington. A. R. G. was supported in part by a NOAA Climate and Global Change Postdoctoral Fellowship. K. S. J acknowledges support from the David and Lucile Packard Foundation through the Monterey Bay Aquarium Research Institute. S. M. B. was supported in part by the Carbon Mitigation Initiative (CMI) project at Princeton University, sponsored by BP. Input from R. Feely, L. Juranek, B. Carter, A. Dickson, and the SOCCOM carbon working group is gratefully acknowledged. We thank P. Landsch{\"u}tzer for generously providing the Global Carbon Budget 2017 flux estimate. All float data used in this study are archived at http://doi.org/10.6075/J0PG1PX7. Shipboard data used in calibration and adjustment are available at CCHDO (https://cchdo.ucsd.edu/) and CDIAC (http://cdiac.ornl.gov/oceans/SOCCOM/ SOCCOM.html). ERA-Interim Reanalysis output was obtained from ECMWF (http://apps.ecmwf.int/datasets/), and ASCAT daily gridded mean wind fields were downloaded from CERSAT (http://cersat.ifremer.fr/data/products/ catalogue). Cape Grim Observatory data are available from CSIRO (http://www.csiro.au/greenhouse-gases). Sea ice data were retrieved from the National Snow and Ice Data Center (http://nsidc.org/data; Data Sets NSIDC-0051 and NSIDC-0081). Surface pCO2 data were obtained from the Surface Ocean CO2 Atlas (SOCAT; https://www.socat.info/), an international effort endorsed by the International Ocean Carbon Coordination Project (IOCCP), the Surface Ocean Lower Atmosphere Study (SOLAS), and the Integrated Marine Biogeochemistry and Ecosystem Research program (IMBER), to deliver a uniformly quality-controlled surface ocean CO2 database. The many researchers and funding agencies responsible for the collection of data and quality control are thanked for their contributions to SOCAT. The gridded flux estimate from Funding Information: This work was sponsored by the U.S. National Science Foundation (NSF) through the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project under the PLR-1425989 to J.?L.?S., supplemented by National Aeronautics and Space Administration Award NNX14AP49G. Logistical support for SOCCOM in the Southern Ocean was provided by NSF through the U.S. Antarctic Program and the U.S. GO-SHIP program, Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), and Germany's Alfred Wegener Institute (AWI). Additionally, we acknowledge support from U.S. Argo through National Oceanic and Atmospheric Administration (NOAA) grant NA17RJ1232 to the University of Washington. A.?R.?G. was supported in part by a NOAA Climate and Global Change Postdoctoral Fellowship. K.?S.?J acknowledges support from the David and Lucile Packard Foundation through the Monterey Bay Aquarium Research Institute. S.?M.?B. was supported in part by the Carbon Mitigation Initiative (CMI) project at Princeton University, sponsored by BP. Input from R. Feely, L. Juranek, B. Carter, A. Dickson, and the SOCCOM carbon working group is gratefully acknowledged. We thank P. Landsch?tzer for generously providing the Global Carbon Budget 2017 flux estimate. All float data used in this study are archived at http://doi.org/10.6075/J0PG1PX7. Shipboard data used in calibration and adjustment are available at CCHDO (https://cchdo.ucsd.edu/) and CDIAC (http://cdiac.ornl.gov/oceans/SOCCOM/SOCCOM.html). ERA-Interim Reanalysis output was obtained from ECMWF (http://apps.ecmwf.int/datasets/), and ASCAT daily gridded mean wind fields were downloaded from CERSAT (http://cersat.ifremer.fr/data/products/catalogue). Cape Grim Observatory data are available from CSIRO (http://www.csiro.au/greenhouse-gases). Sea ice data were retrieved from the National Snow and Ice Data Center (http://nsidc.org/data; Data Sets NSIDC-0051 and NSIDC-0081). Surface pCO2 data were obtained from the Surface Ocean CO2 Atlas (SOCAT; https://www.socat.info/), an international effort endorsed by the International Ocean Carbon Coordination Project (IOCCP), the Surface Ocean Lower Atmosphere Study (SOLAS), and the Integrated Marine Biogeochemistry and Ecosystem Research program (IMBER), to deliver a uniformly quality-controlled surface ocean CO2 database. The many researchers and funding agencies responsible for the collection of data and quality control are thanked for their contributions to SOCAT. The gridded flux estimate from Takahashi et al. () is available at http://www.ldeo.columbia.edu/res/pi/CO2/carbondioxide/pages/air_sea_flux_2000.html. The Global Carbon Budget 2017 air-sea flux estimate is available by contacting P. Landsch?tzer. World Ocean Atlas 2013 gridded nitrate estimates were obtained from https://www.nodc.noaa.gov/OC5/woa13/woa13data.html, and the Roemmich-Gilson Argo Climatology is available from http://sio-argo.ucsd.edu/RG_Climatology.html. Publisher Copyright: {\textcopyright}2018. American Geophysical Union. All Rights Reserved.",
year = "2018",
month = sep,
day = "16",
doi = "10.1029/2018GL078013",
language = "English (US)",
volume = "45",
pages = "9049--9057",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "17",
}