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Abstract Marine heatwaves have become more frequent and intense under anthropogenic warming, posing increasing threats to marine ecosystems and coastal societies, necessitating a better understanding of their mechanism and predictability. Here we show how ocean dynamics modulate marine heatwaves globally by comparing dynamic and slab ocean climate model simulations. We discover that ocean dynamics significantly promote marine heatwave intensity and duration in mid-to-high latitude oceans, as well as the eastern tropical Pacific where marine heatwaves are inherently linked to extreme El Niño events. Our mixed-layer heat budget analysis unravels that heat accumulation during marine heatwave episodes is strongly influenced by vertical mixing and horizontal transport processes, so that warm sea surface temperature extremes in dynamic ocean differ in magnitude and evolution rhythm from those in slab ocean. We further find robust multi-year potential predictability of marine heatwave in the North Atlantic with a dynamic ocean, owing primarily to the predictability of the Atlantic Meridional Overturning Circulation. Our findings emphasize the irreplaceable role of oceanic dynamics in marine heatwave evolution and predictability, with important implications for future climate extreme prediction and adaptation strategies.
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This content will become publicly available on December 1, 2027
Persistent Northeast Pacific marine heatwaves are sensitive to the seasonality of tropical and North Pacific dynamics
Northeast Pacific marine heatwaves occur year-round but are shaped by seasonally-varying dynamics including El Niño-Southern Oscillation (ENSO) and North Pacific atmosphere-ocean interactions. Using a data-driven cyclostationary linear inverse model constructed from 64 years of monthly sea surface temperature and height reanalyses, we demonstrate that longer-lived marine heatwaves preferentially begin in winter, when ENSO teleconnections and oceanic memory most strongly influence event amplification. Springtime subsurface storage and subsequent fall/winter reemergence of thermal anomalies drive extended persistence through wintertime re-intensification. While intense events can also begin in summer, without strong ENSO and reemergence dynamics they rarely persist. The relative importance of tropical forcing versus North Pacific upper-ocean dynamics varies by region and season, producing distinct marine heatwave “flavors” linked to different ENSO types or to internal North Pacific processes alone. These findings reveal how seasonal phase-locking drives marine heatwave evolution, with implications for predictability and marine ecosystem impacts.
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- Award ID(s):
- 2311162
- PAR ID:
- 10701831
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Communications Earth & Environment
- Volume:
- 7
- Issue:
- 1
- ISSN:
- 2662-4435
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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