1. Interhemispheric Contrasts of Ocean Heat Content Change Reveals Distinct Fingerprints of Anthropogenic Climate Forcings.
- Author
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Shi, Jia‐Rui, Wijffels, Susan E., Kwon, Young‐Oh, and Xie, Shang‐Ping
- Subjects
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ENTHALPY , *OCEAN , *GREENHOUSE gases , *OCEAN circulation , *GREENHOUSE effect - Abstract
During recent decades, both greenhouse gases (GHGs) and anthropogenic aerosols (AAs) drove major changes in the Earth's energy imbalance. However, their respective fingerprints in changes to ocean heat content (OHC) have been difficult to isolate and detect when global or hemispheric averages are used. Based on a pattern recognition analysis, we show that AAs drive an interhemispheric asymmetry within the 20°‐35° latitude band in historical OHC change due to the southward shift of the atmospheric and ocean circulation system. This forced pattern is distinct from the GHG‐induced pattern, which dominates the asymmetry in higher latitudes. Moreover, it is found that this significant aerosol‐forced OHC trend pattern can only be captured in analyzed periods of 20 years or longer and including 1975–1990. Using these distinct spatiotemporal characteristics, we show that the fingerprint of aerosol climate forcing in ocean observations can be distinguished from both the stronger GHG‐induced signals and internal variability. Plain Language Summary: The increase in global ocean heat content (OHC) is a good indicator of the combined effect of greenhouse gas (GHG) warming of Earth's climate system and anthropogenic aerosol (AA) cooling. In this study, we focus on the detection of the OHC change driven by AAs by separating it from the GHG‐driven changes. Our investigation demonstrates that in climate models, AAs do leave an imprint in the interior ocean which are detectable via an hemispheric asymmetry within the 20°–35° latitude band which develops in the 1975–1990 period. Observations share many features with results from climate models, revealing that AAs have driven distinct changes in the ocean at regional scales. Key Points: A pattern recognition method is applied to extract the aerosol‐induced pattern of interhemispheric ocean heat content (OHC) changeAnthropogenic aerosols dominate the historical interhemispheric OHC asymmetry within the 20°–35° latitude band over the 1975–1990 periodObserved OHC changes have an asymmetry that is consistent with the aerosol‐induced OHC fingerprint [ABSTRACT FROM AUTHOR]
- Published
- 2023
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