Low ocean-floor rises regulate subpolar sea surface temperature by forming baroclinic jets

作者：Humio Mitsudera, Toru Miyama, Hajime Nishigaki, Takuya Nakanowatari, Hatsumi Nishikawa, Tomohiro Nakamura, Taku Wagawa, Ryo Furue, Yosuke Fujii, Shin‐ichi Ito · 发表于：Nature Communications · 年份：2018 · DOI：10.1038/s41467-018-03526-z · 被引用次数：25 · 研究领域：Climate variability and models、Oceanographic and Atmospheric Processes、Geology and Paleoclimatology Research

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.