caa a22 4500 605455457 CHVBK 20210128100212.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s10872-015-0301-9 doi (NATIONALLICENCE)springer-10.1007/s10872-015-0301-9 Vertical and horizontal structures of the North Pacific subtropical gyre axis [Elektronische Daten] [Masafumi Kimizuka, Fumiaki Kobashi, Atsushi Kubokawa, Naoto Iwasaka] Mean structures of the North Pacific subtropical gyre are investigated using Argo float observations and several wind stress products, with a particular focus on the gyre axis, which is defined as a large-scale boundary between eastward motions on the northern part of the subtropical gyre and westward motions on the southern part. Structures of the gyre axis are different between the regions east and west of about 180°. In the west, the gyre axis is affected by the strong Kuroshio Extension jet, showing discrepancy with features expected from the Sverdrup balance and ventilated thermocline theory. In the east, depth-integrated geostrophic circulation displays the two gyre axes at about 25°N and 30°N in association with a local cyclonic wind stress curl anomaly. It is expected from the Sverdrup balance that the two gyre axes would extend to the west across the subtropical gyre, but the actual geostrophic circulation exhibits only one gyre axis around 30°N to the west. The vertical structure of the subtropical gyre exhibits a remarkable northward shift of the gyre axis with depth in the east, consistent with the southward decrease in the thickness of density layers around the gyre axis, while the northward shift is less obvious in the west, where the gyre axis lies along the southern flank of the Kuroshio Extension. The gyre shift is relatively smaller in the central mode water (CMW) layer due to the horizontal uniformity of the CMW, suggesting a dynamic effect of the CMW on large-scale circulations of the subtropical gyre. The Oceanographic Society of Japan and Springer Japan, 2015 North Pacific subtropical gyre nationallicence Wind-driven circulation nationallicence Gyre axis nationallicence Sverdrup balance nationallicence Ventilated thermocline theory nationallicence Kimizuka Masafumi Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Etchujima 2-1-6, 135-8533, Koto-Ku, Tokyo, Japan aut Kobashi Fumiaki Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Etchujima 2-1-6, 135-8533, Koto-Ku, Tokyo, Japan aut Kubokawa Atsushi Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan aut Iwasaka Naoto Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Etchujima 2-1-6, 135-8533, Koto-Ku, Tokyo, Japan aut Journal of Oceanography Springer Japan 71/4(2015-08-01), 409-425 0916-8370 71:4<409 2015 71 10872 https://doi.org/10.1007/s10872-015-0301-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10872-015-0301-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kimizuka Masafumi Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Etchujima 2-1-6, 135-8533, Koto-Ku, Tokyo, Japan aut NATIONALLICENCE 700 1- Kobashi Fumiaki Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Etchujima 2-1-6, 135-8533, Koto-Ku, Tokyo, Japan aut NATIONALLICENCE 700 1- Kubokawa Atsushi Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan aut NATIONALLICENCE 700 1- Iwasaka Naoto Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Etchujima 2-1-6, 135-8533, Koto-Ku, Tokyo, Japan aut NATIONALLICENCE 773 0- Journal of Oceanography Springer Japan 71/4(2015-08-01), 409-425 0916-8370 71:4<409 2015 71 10872