POSTER SESSION 4
10:30–12:30, Thursday, September 17
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1342 | POSTER 228
SOUTHERN OCEAN CARBON FROM SPACE: MULTI-SENSOR OCEAN COLOR ESTIMATES OF AIR–SEA CO₂ FLUX REVEAL THE IMPORTANCE OF THE ANTARCTIC COASTAL ZONE
The Southern Ocean is usually considered a CO₂ sink, yet uncertainty remains about the magnitude of carbon uptake and even the sign of the flux. Here, we exploit the multi-sensor harmonized ocean color record from the Ocean Colour Climate Change Initiative (OC-CCI) to create an ocean color-based air-sea carbon flux estimate. OC-CCI is preferred for icy coasts because POLYMER atmospheric correction coincidentally mitigates adjacency effects caused by bright snow and ice surfaces. We estimate average CO₂ uptake versus outgassing conditions for the Southern Ocean by coupling ship-based pCO₂ data with satellite ocean color data. This ocean color-based estimate is then analyzed over the seasonal cycle and compared at annual timescales with flux estimates from aircraft, ships, models, and BGC-Argo-floats. In the Antarctic coastal zone, where high phytoplankton biomass drives tight coupling between air-sea carbon flux and Chl-a concentrations at monthly time scales. Preliminary estimates suggest that the Southern Ocean south of 45°S is approximately neutral with respect to net annual ocean color-based air-sea CO₂ flux. However, coastal Antarctic waters exert a disproportionately large influence on regional carbon uptake, and areas with high phytoplankton biomass (Chl-a > 1 mg m-3) are associated with negative ΔpCO₂ (uptake). Results highlight the contrast between the offshore open-ocean regions and the coastal zone where biology is a major driver. Looking to the future, accurately capturing this spatially variable nature of the Southern Ocean air-sea carbon flux from satellite ocean color may require regionally tuned algorithms capable of resolving Antarctic coastal waters’ unique bio-optical properties.
Jessica Turner, Old Dominion University, [email protected], https://orcid.org/0000-0003-3392-0316
Heidi Dierssen, University of Connecticut, [email protected], https://orcid.org/0000-0003-4276-5530
Amanda Fay, Columbia University and Lamont-Doherty Earth Observatory, [email protected], https://orcid.org/0000-0003-3534-1932
Heather Kim, Woods Hole Oceanographic Institution, [email protected], https://orcid.org/0000-0002-1280-3340
David Munro, Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, [email protected], https://orcid.org/0000-0002-1373-7402
Oscar Schofield, Rutgers University, [email protected], https://orcid.org/0000-0003-2359-4131
Eva Scrivner, University of Connecticut, [email protected], https://orcid.org/0009-0008-6852-611X
Sharon Stammerjohn, Institute of Arctic and Alpine Research, University of Colorado Boulder, [email protected], https://orcid.org/0000-0002-1697-8244
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
