Global impacts of recent Southern Ocean cooling

Since the beginning of the satellite era, Southern Ocean sea surface temperatures (SSTs) have cooled, despite global warming. While observed Southern Ocean cooling has previously been reported to have minimal impact on the tropical Pacific, the efficiency of this teleconnection has recently shown to...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences
Main Authors: Kang, Sarah M., Yu, Yue, Deser, Clara, Zhang, Xiyue, Kang, In-Sik, Lee, Sun-Seon, Rodgers, Keith B., Ceppi, Paulo
Format: Text
Language:English
Published: National Academy of Sciences 2023
Subjects:
Physical Sciences
Antarctic
Pacific
Southern Ocean
aleutian low
Antarc*
Sea ice
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10372617/
http://www.ncbi.nlm.nih.gov/pubmed/37459536
https://doi.org/10.1073/pnas.2300881120
Description
Summary:Since the beginning of the satellite era, Southern Ocean sea surface temperatures (SSTs) have cooled, despite global warming. While observed Southern Ocean cooling has previously been reported to have minimal impact on the tropical Pacific, the efficiency of this teleconnection has recently shown to be mediated by subtropical cloud feedbacks that are highly model-dependent. Here, we conduct a coupled model intercomparison of paired ensemble simulations under historical radiative forcing: one with freely evolving SSTs and the other with Southern Ocean SST anomalies constrained to follow observations. We reveal a global impact of observed Southern Ocean cooling in the model with stronger (and more realistic) cloud feedbacks, including Antarctic sea–ice expansion, southeastern tropical Pacific cooling, northward-shifted Hadley circulation, Aleutian low weakening, and North Pacific warming. Our results therefore suggest that observed Southern Ocean SST decrease might have contributed to cooler conditions in the eastern tropical Pacific in recent decades.

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