Japan Geoscience Union Meeting 2024

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[J] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-CG Complex & General

[A-CG44] Kuroshio Large Meander

Wed. May 29, 2024 9:00 AM - 10:15 AM 106 (International Conference Hall, Makuhari Messe)

convener:Hatsumi Nishikawa(Japan Agency for Marine-Earth Science and Technology), Hidetaka Hirata(Rissho University), Norihisa Usui(Meteorological Research Institute), KUSAKA AKIRA(National Research and Development Agency, Japan Fisheries Research and Education Agency. Fisheries Resources Institute), Chairperson:Hatsumi Nishikawa(Atmosphere and Ocean Research Institute, University of Tokyo), Hidetaka Hirata(Rissho University), Norihisa Usui(Meteorological Research Institute), KUSAKA AKIRA(National Research and Development Agency, Japan Fisheries Research and Education Agency. Fisheries Resources Institute)

9:00 AM - 9:15 AM

[ACG44-01] Monitoring short-term Kuroshio SSH variations over the Izu Ridge by ferry-board GNSS and SWOT altimetry data

*Kaoru Ichikawa1, Jyoshiro Noda1, Kei Yufu1, Ryosuke Sakemi1 (1.Research Institute for Applied Mechanics, Kyushu University)

Keywords:the Kuroshio, the Izu Ridge, ferry-board GNSS, SWOT altimeter

The Kuroshio south of Japan has taken a large meandering path for a long period. Together with variations of the wind stress and eddy activities in the North Pacific, significant bottom topography of the Izu Ridge is one of factors affecting the generation and degeneration of the large meander. Therefore, frequent monitoring of the Kuroshio over the Izu Ridge is required, but short-term variations of the Kuroshio are not well observed due to the absence of proper tracks of satellite altimeters over the Izu Ridge. In this study, we have started GNSS observations on a ferryboat “Tachibana Maru” sailing between Takeshiba Port and Hachijo-jima Island, which crosses the Kuroshio over the Izu Ridge twice a day. Among various positioning methods, Precise Point Positioning (PPP) can provide reasonable daily SSH variations of the Kuroshio, except in the vicinity of islands. In addition, beta pre-validated wide-swath SWOT altimeter data can provide, although intermittently, spatial extension of the SSH variations observed by the along-track ferry GNSS data. Significant examples will be shown at the presentation.