FN Archimer Export Format PT J TI Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean BT AF SASAKI, Hideharu KLEIN, Patrice SASAI, Yoshikazu QIU, Bo AS 1:1;2:2;3:3;4:4; FF 1:;2:;3:;4:; C1 JAMSTEC, Applicat Lab, Kanazawa Ku, 3173-25 Showa Machi, Yokohama, Kanagawa 2360001, Japan. IFREMER CNRS UBO IRD, Lab Oceanog Phys & Spatiale, Plouzane, France. JAMSTEC, Res & Dev Ctr Global Change, Yokohama, Kanagawa, Japan. Univ Hawaii Manoa, Dept Oceanog, Honolulu, HI 96822 USA. C2 JAMSTEC, JAPAN CNRS, FRANCE JAMSTEC, JAPAN UNIV HAWAII MANOA, USA UM LOPS IF 1.575 TC 52 UR https://archimer.ifremer.fr/doc/00392/50347/51110.pdf LA English DT Article DE ;Submesoscale turbulence;Scale interactions;Mixed-layer instability;High-resolution simulations;North Pacific AB The kinetic energy (KE) seasonality has been revealed by satellite altimeters in many oceanic regions. Question about the mechanisms that trigger this seasonality is still challenging. We address this question through the comparison of two numerical simulations. The first one, with a 1/10° horizontal grid spacing, 54 vertical levels, represents dynamics of physical scales larger than 50 km. The second one, with a 1/30° grid spacing, 100 vertical levels, takes into account the dynamics of physical scales down to 16 km. Comparison clearly emphasizes in the whole North Pacific Ocean, not only a significant KE increase by a factor up to three, but also the emergence of seasonal variability when the scale range 16–50 km (called submesoscales in this study) is taken into account. But the mechanisms explaining these KE changes display strong regional contrasts. In high KE regions, such the Kuroshio Extension and the western and eastern subtropics, frontal mixed-layer instabilities appear to be the main mechanism for the emergence of submesoscales in winter. Subsequent inverse kinetic energy cascade leads to the KE seasonality of larger scales. In other regions, in particular in subarctic regions, results suggest that the KE seasonality is principally produced by larger-scale instabilities with typical scales of 100 km and not so much by smaller-scale mixed-layer instabilities. Using arguments from geostrophic turbulence, the submesoscale impact in these regions is assumed to strengthen mesoscale eddies that become more coherent and not quickly dissipated, leading to a KE increase. PY 2017 PD SEP SO Ocean Dynamics SN 1616-7341 PU Springer Heidelberg VL 67 IS 9 UT 000407395600007 BP 1195 EP 1216 DI 10.1007/s10236-017-1083-y ID 50347 ER EF