biostudies-literatureUnknown9(1)Mitsudera HSea surface temperature (SST) fronts in mid- to high-latitude oceans have significant impacts on extratropical atmospheric circulations and climate. In the western subarctic Pacific, sharp SST fronts form between the cold subarctic water and the recently found quasi-stationary jets that advect warm waters originating in the Kuroshio northeastward. Here we present a new mechanism of the jet formation paying attention to the propagation of baroclinic Rossby waves that is deflected by eddy-driven barotropic flows over bottom rises, although their height is low (~500 m) compared with the depth of the North Pacific Ocean (~6000 m). Steered by the barotropic flows, Rossby waves bring a thicker upper layer from the subtropical gyre and a thinner upper layer from the subarctic gyre, thereby creating a thickness jump, hence a surface jet, where they converge. This study reveals an overlooked role of low-rise bottom topography in regulating SST anomalies in subpolar oceans.Nature communications1190https://www.ebi.ac.uk/biostudies/studies/S-EPMC5864925biostudies-literatureLow ocean-floor rises regulate subpolar sea surface temperature by forming baroclinic jets.PMC5864925Miyama TMitsudera HWagawa TFujii YNishikawa HNishigaki HNakamura TIto SFurue RNakanowatari TfalseLow ocean-floor rises regulate subpolar sea surface temperature by forming baroclinic jets.Sea surface temperature (SST) fronts in mid- to high-latitude oceans have significant impacts on extratropical atmospheric circulations and climate. In the western subarctic Pacific, sharp SST fronts form between the cold subarctic water and the recently found quasi-stationary jets that advect warm waters originating in the Kuroshio northeastward. Here we present a new mechanism of the jet formation paying attention to the propagation of baroclinic Rossby waves that is deflected by eddy-driven barotropic flows over bottom rises, although their height is low (~500 m) compared with the depth of the North Pacific Ocean (~6000 m). Steered by the barotropic flows, Rossby waves bring a thicker upper layer from the subtropical gyre and a thinner upper layer from the subarctic gyre, thereby creating a thickness jump, hence a surface jet, where they converge. This study reveals an overlooked role of low-rise bottom topography in regulating SST anomalies in subpolar oceans.2018-01-01T00:00:00Z2018 Mar2022-02-09T09:22:26.101Z2019-03-26T23:20:42ZS-EPMC58649252956800910.1038/s41467-018-03526-z