Recent multi-decadal Southern Ocean surface cooling unlikely caused by Southern Annular Mode trends
Dong, Y., Polvani, L. M., Bonan, D. B.. (2023). Recent multi-decadal Southern Ocean surface cooling unlikely caused by Southern Annular Mode trends. Geophysical Research Letters, doi:https://doi.org/10.1029/2023GL106142
| Title | Recent multi-decadal Southern Ocean surface cooling unlikely caused by Southern Annular Mode trends |
|---|---|
| Genre | Article |
| Author(s) | Yue Dong, L. M. Polvani, D. B. Bonan |
| Abstract | Over recent decades, the Southern Ocean (SO) has experienced multi-decadal surface cooling despite global warming. Earlier studies have proposed that recent SO cooling has been caused by the strengthening of surface westerlies associated with a positive trend of the Southern Annular Mode (SAM) forced by ozone depletion. Here we revisit this hypothesis by examining the relationships between the SAM, zonal winds and SO sea-surface temperature (SST). Applying a low-frequency component analysis to observations, we show that while positive SAM anomalies can induce SST cooling as previously found, this seasonal-to-interannual modulation makes only a small contribution to the observed long-term SO cooling. Global climate models well capture the observed interannual SAM-SST relationship, and yet generally fail to simulate the observed multi-decadal SO cooling. The forced SAM trend in recent decades is thus unlikely the main cause of the observed SO cooling, pointing to a limited role of the Antarctic ozone hole. |
| Publication Title | Geophysical Research Letters |
| Publication Date | Dec 16, 2023 |
| Publisher's Version of Record | https://doi.org/10.1029/2023GL106142 |
| OpenSky Citable URL | https://n2t.org/ark:/85065/d72r3wr3 |
| OpenSky Listing | View on OpenSky |
| CGD Affiliations | CGDAO |