The Role of Ocean Circulation in Southern Ocean Heat Uptake, Transport, and Storage Response to Quadrupled CO₂

Journal Article · Mon Oct 31 00:00:00 EDT 2022 · Journal of Climate

DOI:https://doi.org/10.1175/jcli-d-22-0160.1· OSTI ID:1905855

Li, Qiuxian ^[1]; Luo, Yiyong ^[1]; Lu, Jian ^[2]; Liu, Fukai ^[1]

---

1. Ocean University of China (China); Qingdao National Laboratory for Marine Science and Technology (China)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Science and Global Change Div. (ASGC)

In response to quadrupled CO₂, the Southern Ocean primarily uptakes excess heat around 60°S, which is then redistributed by the northward ocean heat transport (OHT) and mostly stored in the ocean or released back to the atmosphere around 45°S. However, the relative roles of mean ocean circulation and ocean circulation change in the uptake and redistribution of heat in the Southern Ocean remain controversial. Here, in this study, a set of climate model experiments embedded with a novel partial coupling technique are used to separate the roles of mean ocean circulation (passive component) and ocean circulation change (active component). For the ocean heat uptake (OHU) response, the mean ocean circulation and ocean circulation change are of equal importance. The OHT response south of 50°S is mainly determined by mean ocean circulation, while the ocean circulation change generates an anomalous southward OHT north of 50°S. A heat budget analysis finds that the divergence of passive OHT acts to balance the passive surface heat gain to the south of ~50°S, while the convergence of active OHT acts to balance the active surface heat loss to the north of ~50°S. Intriguingly, all the increase in ocean heat storage (OHS) is attributable to the passive component, with the ocean circulation change playing almost no role. In the Southern Ocean, both the active and the passive ocean heat transports are overcompensated by the reverse atmospheric heat transport via the Bjerknes compensation.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); National Key Research and Development Program of China; National Natural Science Foundation of China (NSFC)
• Grant/Contract Number: AC05-76RL01830; AC02-05CH11231; 2018YFA0605702; 41976006; 41906002; 42230405
• OSTI ID: 1905855
• Report Number(s): PNNL-SA-171138
• Journal Information: Journal of Climate, Vol. 35, Issue 22; ISSN 0894-8755
• Publisher: American Meteorological Society
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
Southern Ocean
Ocean circulation
Heat budgets/fluxes