Modeling the Atlantic Multidecadal Oscillation: The High-Resolution Ocean Brings the Timescale; the Atmosphere, the Amplitude
The Atlantic Multidecadal Oscillation (AMO) is the leading mode of low-frequency variability in sea surface temperatures in the Atlantic, affecting global climate. Higher-resolution models substantially improve AMO simulations, closely matching observed periods and amplitudes, yet the reason for the...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Association for the Advancement of Science (AAAS)
2025-01-01
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| Series: | Ocean-Land-Atmosphere Research |
| Online Access: | https://spj.science.org/doi/10.34133/olar.0085 |
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| Summary: | The Atlantic Multidecadal Oscillation (AMO) is the leading mode of low-frequency variability in sea surface temperatures in the Atlantic, affecting global climate. Higher-resolution models substantially improve AMO simulations, closely matching observed periods and amplitudes, yet the reason for the improvement remains unclear. Here, using 4 experiments conducted within the Alfred Wegener Institute Climate Model with different atmospheric and oceanic resolutions, we found that models with a high-resolution ocean capture the positive feedback between the AMO and the Fram Strait sea ice export mediated by the Atlantic Meridional Overturning Circulation through a more realistic simulation of North Atlantic currents, extending the AMO period to 40 to 80 years. Further increasing the atmospheric resolution results in an AMO amplitude closer to observations due to stronger coupling between atmospheric blocking and Arctic sea ice. This indicates the importance of higher resolution in models for simulating the interaction between synoptic-scale atmospheric processes and long-term ocean variability, which is crucial for AMO simulations. |
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| ISSN: | 2771-0378 |