The Response of Sea Surface Temperature to Atmospheric Rivers

Atmospheric rivers (ARs), responsible for extreme weather conditions, are mid-latitude systems that cause significant damage to coastal areas. While forecasting ARs beyond 10 days remains a challenge, past research suggests potential benefits may come from properly accounting for the changes in sea surface temperature (SST) through air-sea interactions. We investigate the impact of ARs on SST over the North Pacific by analyzing 25 years of ocean reanalysis data using an SST budget equation. We show that ARs increase SST in the extratropics, while ocean dynamics dampen over 10% of the warming that would otherwise arise from atmospheric forcing. Ageostrophic advection, vertical diffusion, and entrainment are the most important ocean processes in modulating the SST tendency response. We also discuss the regional SST tendency response, including the strong marine warming region where stratocumulus clouds play an important role, and coastal California where ageostrophic advection dominates the SST response to ARs.