Climate-driven variability of the Southern Ocean CO2 sink
OPEN ACCESS
Loading...
Author / Producer
Date
2023-06-26
Publication Type
Journal Article
ETH Bibliography
yes
Citations
Altmetric
OPEN ACCESS
Data
Rights / License
Abstract
The Southern Ocean is a major sink of atmospheric CO2, but the nature and magnitude of its variability remains uncertain and debated. Estimates based on observations suggest substantial variability that is not reproduced by process-based ocean models, with increasingly divergent estimates over the past decade. We examine potential constraints on the nature and magnitude of climate-driven variability of the Southern Ocean CO2 sink from observation-based air-sea O2 fluxes. On interannual time scales, the variability in the air-sea fluxes of CO2 and O2 estimated from observations is consistent across the two species and positively correlated with the variability simulated by ocean models. Our analysis suggests that variations in ocean ventilation related to the Southern Annular Mode are responsible for this interannual variability. On decadal time scales, the existence of significant variability in the air-sea CO2 flux estimated from observations also tends to be supported by observation-based estimates of O2 flux variability. However, the large decadal variability in air-sea CO2 flux is absent from ocean models. Our analysis suggests that issues in representing the balance between the thermal and non-thermal components of the CO2 sink and/or insufficient variability in mode water formation might contribute to the lack of decadal variability in the current generation of ocean models. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.
Permanent link
Publication status
published
External links
Editor
Book title
Volume
381 (2249)
Pages / Article No.
20220055
Publisher
Royal Society
Event
Edition / version
Methods
Software
Geographic location
Date collected
Date created
Subject
Southern ocean; Carbon sink; Climate; Oxygen; Interannual
Organisational unit
03731 - Gruber, Nicolas / Gruber, Nicolas
Notes
Funding
821003 - Climate-Carbon Interactions in the Coming Century (EC)
820989 - Our common future ocean – quantifying coupled cycles of carbon, oxygen, and nutrients for determining and achieving safe operating spaces with respect to tipping points (EC)
862923 - Atlantic ECOsystems assessment, forecasting & sustainability (EC)
820989 - Our common future ocean – quantifying coupled cycles of carbon, oxygen, and nutrients for determining and achieving safe operating spaces with respect to tipping points (EC)
862923 - Atlantic ECOsystems assessment, forecasting & sustainability (EC)