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Abstract The equatorial cold tongue region has not warmed up in response to historical radiative forcing in the real world, contrary to the strong warming often simulated by climate models. Here we demonstrate that climate models fail to represent one or both of the key processes driving observed sea surface temperature (SST) pattern formation: a realistic surface wind stress pattern shaping subsurface cooling through wind‐driven circulation changes, and effective connectivity between subsurface and surface temperatures via upwelling and mixing. Consequently, none of the models approximate the observed lack of cold tongue SST warming and strengthening of zonal SST gradient across the equatorial Pacific. Furthermore, those that come closest achieve this due to interhemispheric warming differences rather than equatorial dynamics as observed. Addressing different origins of subsurface cooling in observations and simulations, and how they connect to SST, will lead to improved understanding of tropical Pacific SST changes to date and how they will evolve in the future.
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Uncertain future of sustainable fisheries environment in eastern boundary upwelling zones under climate change
Abstract Upwelling along ocean eastern boundaries is expected to intensify due to coastal wind strengthening driven by increasing land-sea contrast according to the Bakun hypothesis. Here, the latest high-resolution climate simulations that exhibit drastic improvements of upwelling processes reveal far more complex future upwelling changes. The Southern Hemisphere upwelling systems show a future strengthening in coastal winds with a rapid coastal warming, whereas the Northern Hemisphere coastal winds show a decrease with a comparable warming trend. The Bakun mechanism cannot explain these changes. Heat budget analysis indicates that temperature change in the upwelling region is not simply controlled by vertical Ekman upwelling, but also influenced by horizontal heat advection driven by strong near-coast wind stress curl that is neglected in the Bakun hypothesis and poorly represented by the low-resolution models in the Coupled Model Intercomparison Project. The high-resolution climate simulations also reveal a strong spatial variation in future upwelling changes, which is missing in the low-resolution simulations.
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- Award ID(s):
- 2137684
- PAR ID:
- 10565859
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Communications Earth & Environment
- Volume:
- 4
- Issue:
- 1
- ISSN:
- 2662-4435
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1038/s43247-023-00681-0
