A5038080834- Arctic and Antarctic ice dynamics
- Oceanographic and Atmospheric Processes
- Ocean Waves and Remote Sensing
- Tropical and Extratropical Cyclones Research
- Methane Hydrates and Related Phenomena
- Cryospheric studies and observations
- Climate variability and models
- Climate change and permafrost
- Coastal and Marine Dynamics
- Marine and environmental studies
- Meteorological Phenomena and Simulations
- Wave and Wind Energy Systems
- Ship Hydrodynamics and Maneuverability
- Geophysics and Gravity Measurements
- Marine and coastal ecosystems
- Coastal and Marine Management
- Underwater Acoustics Research
- Nonlinear Waves and Solitons
- Power Systems and Renewable Energy
- Agricultural Economics and Practices
- Indoor and Outdoor Localization Technologies
- Marine and Coastal Research
- Genetics and Plant Breeding
- Marine Biology and Ecology Research
- Food Industry and Aquatic Biology
The University of Tokyo
2013-2024
Tokyo University of Marine Science and Technology
2022
Dalhousie University
2014-2016
Internal solitary waves in a system of two fluids, silicone oil and water, bounded above by free surface are studied both experimentally theoretically. By adjusting an extra volume released from reservoir, wide range amplitude generated wave tank. Wave profiles as well speeds measured using multiple probes then compared with the weakly nonlinear Korteweg–de Vries (KdV) models strongly Miyata–Choi–Camassa (MCC) models. As density difference between fluids experiment is relatively small...
There is a wide consensus within the polar science, meteorology, and oceanography communities that more in situ observations of ocean, atmosphere, sea ice are required to further improve operational forecasting model skills. Traditionally, volume such measurements has been limited by high cost commercially available instruments. An increasingly attractive solution this issue use instruments produced in-house from open-source hardware, firmware, postprocessing building blocks. In present...
Abstract Arctic sea ice is rapidly decreasing during the recent period of global warming. One significant factors loss oceanic heat transport from lower latitudes. For months formation, variations in surface temperature over Pacific region were highly correlated with Decadal Oscillation (PDO). However, seasonal temperatures recorded their highest values autumn 2018 when PDO index was neutral. It shown that anomalous warm seawater a rapid ocean response to southerly winds associated episodic...
Abstract. Ocean surface waves are known to decay when they interact with sea ice. Wave–ice models implemented in a spectral wave model, e.g. WAVEWATCH III® (WW3), derive the attenuation coefficient based on several different model ice types, i.e. how treats In marginal zone (MIZ) concentration (SIC) < 1, is moderated by SIC: we show that subgrid-scale processes relating SIC and type heterogeneity wave–ice missing accuracy of plays an important role predictability. Satellite-retrieved data...
Abstract. Observations of wave dissipation and dispersion in sea ice are a necessity for the development validation wave–ice interaction models. As composition layer can be extremely complex, most models treat as continuum with effective, rather than independently measurable, properties. While this provides opportunities to fit model observations, it also obscures our understanding interactive processes; particular, hinders ability identify under which environmental conditions these...
The sea ice coverage in the summer Arctic Ocean from Beaufort to Laptev Seas continues decrease, and largest waves western open waters are increasing year by year. By looking into historical wave events ERA-Interim reanalysis data, we discovered that more than half of extreme caused cyclones originating as well mid-latitudes. During September, when ice-free water area becomes each year, percentage has increased around 50% almost 80% last four decades. Moreover, locations these spreading...
Waves in the Marginal Ice Zone Okhotsk Sea are less studied compared to Antarctic and Arctic. In February 2020, wave observations were conducted for first time Sea, during observational program by Patrol Vessel Soya. A buoy was deployed on ice, situ made a ship-borne stereo imaging system Inertial Measurement Unit. ice observed visually aerial photographs drone, while satellite synthetic aperture radar provided basin-wide spatial distribution. On 12 February, swell propagating from east...
The interaction between waves and ice has a crucial impact on the seasonal change in sea extent. However, our comprehension of this phenomenon is restricted by lack observations. In recent years, availability low-cost accurate Inertial Motion Units enabled development affordable wave research devices. Despite advancements designing innovative open-source instruments optimized for deployment floes, their customizability survivability remain limited, especially open waters. This study presents...
A drifting wave-ice buoy (Medusa-766) was deployed at the Lützow-Holm Bay (LHB) marginal ice zone in Antarctica during 63rd Japanese Antarctic Research Expedition to study wave influence on unstable LHB fast ice. Medusa-766 survived winter as it located deep cover with shortest distance ice-free Southern Ocean over 1,000 km; this time, there evidence of 8-cm-height signal position. Using ECMWF's reanalysis data, we show that incoming waves were likely 4-m generated by an extratropical...
Abstract In this study, we investigate the processes of phytoplankton growth and decline in mesoscale eddies western North Pacific Ocean based on situ chlorophyll data obtained from 52 cruises conducted by Japan Meteorological Agency together with idealized numerical simulations. Both observation model results suggest that chlorophyll/phytoplankton concentrations are higher cold than warm near‐surface water (z > −70 m). simulation, isopycnal movements associated upwelling/downwelling...
The significant reduction of the sea ice extent in western Arctic has been observed by sustained satellite observations since 1979. opening ocean is now allowing waves to evolve and propagate under presence ice. A better understanding wave-ice interaction necessary for safe shipping over covered Ocean improve climate projection. During R/V Mirai Expedition October 2019, two drifting wave-buoys were concurrently deployed open marginal zone (MIZ) with grease pancake wave conditions at time...
Accurate knowledge of ocean surface waves is crucial for ship design. With the significant advancements in model physics and numerical resources, recent wave hindcast data has potential to provide environmental conditions estimating load design process. To help estimate extreme loads with quantified uncertainty strength assessments structures, this study aims quantify state-of-the-art products. Model was deduced from inter-model comparisons four products after evaluations. For evaluations,...
With the long-term goal of developing an operational forecast system for total water level, we conduct a hindcast study global storm surges Fall 2014 using baroclinic ocean model based on NEMO framework. The has 19 vertical levels, horizontal resolution 1/12°, and is forced by hourly forecasts atmospheric wind air pressure. Our first objective to evaluate model's ability predict sea levels recorded array 257 tide gauges. It shown that can provide reasonable predictions whole test period at...
A prototype OpenMetBuoy (OMB) was deployed alongside a commercial buoy in the central Arctic Ocean, north of Laptev Sea, where there are historically no wave observations available. The inter-buoy comparison showed that OMB measured heights and periods accurately, so data were used to study predictability wave–ice model. first event we studied when both buoys observed sudden decrease significant Hm0, which caused by change wind directions from along ice edge off-ice wind. Ocean Wave Analysis...
The Marginal Ice Zone (MIZ) forms a critical transition region between the ocean and sea ice cover as it protects close further in from effect of steepest most energetic open waves. As waves propagate through MIZ, they get exponentially attenuated. Unfortunately, associated attenuation coefficient is difficult to accurately estimate model, there are still large uncertainties around which mechanisms dominate depending on conditions. This makes challenging predict attenuation, well effective...
Abstract Global M 2 tidal surface currents are predicted using a global baroclinic ocean model with horizontal grid spacing of 1/12° and 19 z‐levels in the vertical. After first showing elevations reasonable agreement observations made by bottom pressure recorders altimeters, evaluated comparing them independent estimates based on observed drifter trajectories. Both can exceed 0.1 m s −1 deep ocean. Internal tides shown to make significant contribution currents. Phase locking internal causes...
The development of a computationally efficient scheme for predicting the global distribution total water level (TWL) is discussed. ocean model barotropic, has horizontal grid spacing 1/12°, and based on NEMO modeling framework. It forced by gravitational potential hourly atmospheric fields 2008. Hourly time was required to resolve S2 tide in air pressure wind. predicted deeper than 400 m nudged TPXO8 "observations" tidal elevation or current using called nudging (Kodaira et al., 2019)....
Abstract Variability in sea ice conditions, combined with strong couplings to the atmosphere and ocean, lead a broad range of complex dynamics. More in-situ measurements are needed better identify phenomena mechanisms that govern growth, drift, breakup. To this end, we have gathered dataset observations drift waves ice. A total 15 deployments were performed over period 5 years both Arctic Antarctic, involving 72 instruments. These provide GPS tracks, The data can, turn, be used for tuning...
The ocean waves in the North Atlantic Ocean are internationally recognized to represent a wave climate suitable for design of merchant ships. However, accumulated knowledge from past indicates that encountered sea states less severe than Standard Wave Data recommended by International Association Classification Society. In this study, we propose statistical model representing storm avoidance ships and apply it newly computed 25-year hindcast (TodaiWW3-NK) Ocean. We derive statistics relates...
Driven by technical advances in low-cost electronics, massive deployment of ocean sensing devices has become increasingly feasible. We have developed an inexpensive MEMS IMU based and solar-powered small wave buoy FZ that makes the intensive deployments possible. After hardware software is described, results test four buoys to Okhotsk Sea with seasonal sea ice coverage February 2022. For reference, commercial Spotter was also deployed one buoys. The comparison shows general a good agreement...
Sea ice is a key element of the global Earth system, with major impact on climate and regional weather. Unfortunately, accurate sea modeling challenging due to diversity complexity underlying physics happening there, relative lack ground truth observations. This especially true for Marginal Ice Zone (MIZ), which area where affected by incoming ocean waves. Waves contribute making dynamic, low survival time buoys deployed MIZ monitor. In 2022-2023, we released 79 OpenMetBuoys (OMBs) around...