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The dominant contribution of Southern Ocean heat uptake to time-evolving radiative feedback in CESM
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  • Yuan-Jen Lin,
  • Yen-Ting Hwang,
  • Jian Lu,
  • Fukai Liu,
  • Brian E. J. Rose
Yuan-Jen Lin
National Taiwan University
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Yen-Ting Hwang
National Taiwan University

Corresponding Author:[email protected]

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Jian Lu
Pacific Northwest National Laboratory (DOE)
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Fukai Liu
Ocean University of China
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Brian E. J. Rose
University at Albany
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Abstract

Radiative feedbacks are found to vary with time in both historical records and future warming projections. Previous studies proposed two factors that determine the variation of radiative feedbacks: (i) the evolution of tropical sea surface warming patterns and (ii) the tropical-extratropical contrast of ocean heat uptake. Our results bridge the two factors by evaluating the remote impact from the extratropical ocean on tropical temperature patterns, accounting for the changes in radiative feedbacks. Based on the Green’s Function approach that quantifies the non-local contributions of regional ocean heat uptake, we show that the net radiative feedback evolution in CESM can be mostly attributed to the heat uptake variations in the Southern Ocean. The enhanced surface warming associated with the weakened heat uptake decades after quadrupling CO2 is not confined over the Southern Ocean, but extends to tropical Southeastern Pacific, which leads to decreasing tropospheric stability and more positive cloud feedbacks.
16 May 2021Published in Geophysical Research Letters volume 48 issue 9. 10.1029/2021GL093302