A5090291385- Oceanographic and Atmospheric Processes
- Marine and coastal ecosystems
- Geology and Paleoclimatology Research
- Tropical and Extratropical Cyclones Research
- Ocean Waves and Remote Sensing
- Arctic and Antarctic ice dynamics
- Climate variability and models
- Marine and environmental studies
- Coastal and Marine Dynamics
- Marine and fisheries research
- Ocean Acidification Effects and Responses
- Isotope Analysis in Ecology
- Methane Hydrates and Related Phenomena
- Geophysics and Gravity Measurements
- Radioactive contamination and transfer
- Geological formations and processes
- Radioactivity and Radon Measurements
- Geological and Geophysical Studies
- Underwater Acoustics Research
- Microbial Applications in Construction Materials
- Archaeology and ancient environmental studies
- Meteorological Phenomena and Simulations
- Geochemistry and Elemental Analysis
- Marine Biology and Ecology Research
- Coastal and Marine Management
Kyushu University
2013-2023
National Fisheries University
1996-2001
Tokyo University of Marine Science and Technology
1993-1998
Using acoustic Doppler current profiler (ADCP) and conductivity‐temperature‐depth (CTD) data sets obtained from 1991 to 1993, volume, freshwater, temperature transports through the Tsushima‐Korea Straits are estimated. To remove tidal currents contained in raw ADCP data, calculated using harmonic constants by surveys 1998 1999. The annual mean range of volume transport straits 2.4 Sv (1 = 10 6 m 3 /s) 0.8 Sv, respectively. These values consistent with those previous studies. annually...
Abstract Turbulent mixing and background current were observed using a microstructure profiler acoustic Doppler profilers in the Tokara Strait, where many seamounts small islands exist within route of Kuroshio East China Sea. Vertical structure water properties greatly modified downstream from shallow seamounts. In lee seamount crest at 200 m depth, modification made flow tend to shear instability, vertical eddy diffusivity is enhanced by nearly 100 times that upstream site, K ρ ∼ O (10 −3...
The newly formed bottom water in the Japan Sea was observed summer of 2001 after severe winter 2000–2001. new water, which northwestern Sea, showed low temperature, high salinity, dissolved oxygen and nutrients concentration compared to old water. distribution indicates that south off Vladivostok, not northern north 43°N, advected observation area. It is suggested formation event occurred late January‐early February 2001, because strong flows faster than 8 cms −1 appeared abruptly from...
The scattering of near‐inertial internal waves (NIIWs) induced at the tips landmasses was investigated by mooring observations using current meters and thermometers in surface layer along peninsulas an island located Japanese coast Japan Sea during fall 2006. Signals NIIWs were found alongshore currents temperatures recorded near seasonal thermocline. signals appeared after wind stress had reached a maximum, they lasted for more than 2 days. Relatively high energy regions due to localized...
Abstract Vertical nitrate fluxes associated with turbulent mixing and upwelling around a small reef in the Kuroshio are quantified by continuously deploying turbulence microstructure profiler an attached submersible ultraviolet analyzer while drifting from upstream to downstream of reef. Flow separations trains Kelvin‐Helmholtz billows (thickness = 60 m) identified using shipboard ADCP echo‐sounder. The diffusivity vigorous reaches up O (10 −1 m 2 s ), resulting strong (1–10 3 mmol −2 day )....
Abstract Although previous studies reported that currents over topographic features, such as seamounts and ridges, cause strong turbulence in close proximity, it has been elusive how far intense spreads toward the downstream. Here, we conducted a series of intensive in-situ observations using state-of-the-art tow-yo microstructure profiler Kuroshio flowing Tokara Strait, south Kyusyu Japan, November 2017, June 2018, 2019, employed high-resolution numerical model to elucidate generation...
The vertical distributions of dissolvable (unfiltered) Fe concentrations in semi‐closed oceanic regions, such as the Japan Sea and Bering Sea, are characterized by a gradual increase with depth intermediate deep waters. However, there is rapid decrease concentration over narrow range between bottom waters constantly lower observed (Japan Basin), probably from injection newly formed water. In addition, western North Pacific Ocean may be due to resuspension sediments seafloor or slope. no...
Between 1996 and 2002, a wide-area research project on anthropogenic radionuclides was carried out in an area covering the Japanese Russian Exclusive Economic Zones of Japan Sea, through collaboration institutes. The aim to investigate migration behavior (90Sr, 137Cs, 239+240Pu) sea. Four expeditions conducted Sea between 2001 2002 found that observed concentrations distributions were similar those previous investigations. Inventories estimated from concentration data indicate larger amounts...
Labile dissolved Fe (DFe, <0.22 μ m fraction) and total dissolvable (TDFe, unfiltered) were examined throughout the water column of northeastern (Japan Basin) mid‐eastern (Yamato basin regions in Japan Sea. We observed extremely high vertically integrated TDFe inventories low nutrient concentrations at surface both basins, probably resulting from atmospheric input to nutrient‐depleted water. DFe basins was characterized by mid‐depth maxima and, below that, a slight decrease with depth...
Abstract Steep oceanic ridges and tidal currents in the Luzon Strait generate some of world’s strongest turbulent mixing. To evaluate impacts turbulence intensity on marine ecosystem, we carried out measurements microstructure biogeochemical hydrography along 21°N during R/V Hakuho Maru cruise, KH-17-5-2, November 2017. We found a kinetic energy dissipation rate exceeding O (10 −7 ) W kg −1 vertical eddy diffusivity −3 m 2 s , two orders magnitude larger than those open ocean, above shallow...