Recent evidence for a strengthening CO2 sink in the Southern Ocean from carbonate system measurements in the Drake Passage (2002-2015)

David R Munro, University of Colorado, Department of Atmospheric and Oceanic Sciences and Institute for Arctic and Alpine Research, Boulder, CO, United States, Nicole S Lovenduski, University of Colorado, Department of Atmospheric and Oceanic Sciences, Boulder, CO, United States, Taro Takahashi, Columbia Univ, Palisades, NY, United States, Britton B Stephens, National Center for Atmospheric Research, Earth Observing Laboratory, Boulder, CO, United States, Timothy Newberger, NOAA Boulder, Global Monitoring Division, Boulder, CO, United States and Colm Sweeney, NOAA ESRL, Global Monitoring Division, Boulder, CO, United States
Abstract:
We present a 13-year (2002-2015) semi-monthly time-series of the partial pressure of CO2 in surface water (pCO2surf) and other carbonate system parameters from the Drake Passage. This record shows a clear increase in the magnitude of the sea-air pCO2 gradient, indicating strengthening of the CO2 sink in agreement with recent large-scale analyses of the world oceans. The rate of increase in pCO2surf north of the Antarctic Polar Front (APF) is similar to the atmospheric pCO2 (pCO2atm) trend, whereas the pCO2surf increase south of the APF is slower than the pCO2atm trend. The high-frequency surface observations indicate that an absence of a winter increase in total CO2 (TCO2) and cooling summer sea surface temperatures are largely responsible for increasing CO2 uptake south of the APF. Muted winter trends in surface TCO2 also provide temporary stability to the carbonate system that is already close to undersaturation with respect to aragonite.
Back to: Updates, Advancements, and Projections on the State of the Ocean Carbon Cycle (SOCC): How the Ocean is "SOCC"ing it to us! III Posters