Submesoscale feedback suppresses marine heatwaves.

Submesoscale feedback reduces marine heatwave severity by up to 18.1% in a global model simulation.

• Why it matters: Understanding the mechanisms controlling MHW intensity and persistence is crucial for accurate climate projections and marine ecosystem protection, yet these mechanisms are not fully known.
• What they did: The study used a submesoscale-permitting global model validated by observational data to identify a feedback where submesoscale vertical heat flux suppresses MHWs during winter, reducing heat flux by 19.4%.
• The result: This feedback decreases MHW intensification by 18.1% and accelerates decay by 21.7%, suggesting that models neglecting this mechanism may overestimate MHW severity and impact future climate predictions.