A5058253888- Oceanographic and Atmospheric Processes
- Climate variability and models
- Arctic and Antarctic ice dynamics
- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Methane Hydrates and Related Phenomena
- Marine and coastal ecosystems
- Climate change and permafrost
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Geological Studies and Exploration
- Geological formations and processes
- Ocean Acidification Effects and Responses
- Tropical and Extratropical Cyclones Research
- Hydrocarbon exploration and reservoir analysis
- Coastal and Marine Dynamics
- Marine Biology and Ecology Research
- Ocean Waves and Remote Sensing
- Aquatic and Environmental Studies
- Marine and environmental studies
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- Coastal and Marine Management
- Paleontology and Stratigraphy of Fossils
- Marine and fisheries research
The University of Tokyo
2016-2025
Sphere Institute
2011-2021
Graduate School USA
2020
Japan Agency for Marine-Earth Science and Technology
2020
American Geophysical Union
2013
University of Alaska Fairbanks
2013
Abstract A new version of the atmosphere–ocean general circulation model cooperatively produced by Japanese research community, known as Model for Interdisciplinary Research on Climate (MIROC), has recently been developed. century-long control experiment was performed using (MIROC5) with standard resolution T85 atmosphere and 1° ocean models. The climatological mean state variability are then compared observations those in a previous (MIROC3.2) two different resolutions (medres, hires),...
Abstract The Atlantic thermohaline circulation (THC) is an important part of the earth's climate system. Previous research has shown large uncertainties in simulating future changes this critical simulated THC response to idealized freshwater perturbations and associated have been intercompared as activity World Climate Research Program (WCRP) Coupled Model Intercomparison Project/Paleo-Modeling Project (CMIP/PMIP) committees. This intercomparison among models ranging from earth system...
As part of the Coupled Model Intercomparison Project, integrations with a common design have been undertaken eleven different climate models to compare response Atlantic thermohaline circulation (THC) time‐dependent change caused by increasing atmospheric CO 2 concentration. Over 140 years, during which concentration quadruples, strength declines gradually in all models, between 10 and 50%. No model shows rapid or complete collapse, despite fairly increase high final . The having strongest...
Abstract The Atlantic meridional overturning circulation (AMOC) represents the zonally integrated stream function of volume transport in Basin. AMOC plays an important role transporting heat meridionally climate system. Observations suggest a by 1.3 PW at 26°N—a latitude which is close to where northward thought reach its maximum. This shapes North region as we know it today. In recent years there has been significant progress both our ability observe nature and simulate numerical models....
A new high-resolution atmosphere-ocean coupled general circulation model named MIROC4h has been developed, and its performance in a 120-year control experiment (including 50-year spin-up) under the present conditions (the year 1950) is examined. The results of by are compared with simulations preindustrial carried out for Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) using previous high- medium-resolution versions model, called MIROC3h MIROC3m, respectively....
Significance The Ross Sea is a major drainage basin for the Antarctic Ice Sheet and contains world’s largest ice shelf. Newly acquired swath bathymetry data sediment cores provide evidence two episodes of ice-shelf collapse. Two novel geochemical proxies, compound specific radiocarbon dating radiogenic beryllium ( 10 Be), constrain timing most recent widespread (∼280,000 km 2 ) breakup as having occurred in late Holocene. Three-dimensional ice-shelf/ocean modeling results comparison with...
[1] Using a high-resolution atmosphere–ocean coupled climate model, responses of the Kuroshio and Extension (KE) to global warming are investigated. In change experiment with atmospheric CO2 concentration ideally increased by 1% year−1, current velocity KE increases, while latitude separation east Japan does not significantly. The increase is up 0.3 m s−1 at 150°E. This acceleration due changes in wind stress over North Pacific consequent spin-up recirculation gyre. currents may affect sea...
We investigate basal melting of all Antarctic ice shelves by a circumpolar shelf‐sea ice‐ocean coupled model and estimate the total 770–944 Gt/yr under present‐day climate conditions. present comparison with previous observational modeling estimates for each shelf. Heat sources are largely different among shelves. Sensitivities to surface air warming enhanced westerly winds over Circumpolar Current investigated from series numerical experiments. In this strongly depends on but is hardly...
Paleo proxy data suggest that the Atlantic meridional overturning circulation (AMOC) was shallower and weaker at Last Glacial Maximum (LGM) than present. In this study, we have identified existence of a thermal threshold AMOC which may explain why many coupled climate models fail to simulate during LGM. By using results obtained from model conducting sensitivity simulations with an ocean general model, found sudden transition present‐day glacial occurs when gradually change degree surface...
Abstract A series of zonal currents in the Pacific Ocean is investigated using eddy-permitting ocean general circulation models. The subsurface are classified into two parts: one a broad flows that has meridional pattern slanting poleward with increasing depth and other finescale jets scale 3°–5° formed each flow. basic for similar between coarse-resolution model thought to be response wind forcing. part embedded flow explained by anomalous local Most them, however, seem mainly created...
Deep Pacific circulation is investigated by using a World Ocean model with depth-dependent vertical diffusivity. Vertical diffusivity estimated from observations, 0.1 × 10−4 m2 s−1 for the upper layer and 3.0 bottom layer, adopted. Comparison made between cases different at middepths. With larger middepths, deep becomes stronger. This due to enhanced heat exchange thermocline water through more intense diffusion The below warmed that cooled whole basin. leads loss sea surface, causing...
The winter dipole anomaly (DA) in the Arctic atmosphere and its contribution to sea ice export are investigated by using a high‐resolution coupled global general circulation model. spatial distributions of first two leading EOF modes mean level pressure (SLP) geopotential height at 500 hPa north 70°N obtained long‐term simulation (1900–2010) highly similar those derived from National Center for Environmental Prediction Atmospheric Research (NCEP/NCAR) reanalysis datasets (1948–2004)....
Using an ice‐ocean coupled model with fine horizontal resolution around East Antarctica, sea ice production and dense shelf water (DSW) formation in coastal polynyas are investigated. The reproduces well the locations of high there. DSW is formed over continental shelves under a number polynyas. A threshold density, beyond which net takes place, largely different among densest most vigorous occurs Cape Darnley Mertz‐Ninnis Glacier followed by somewhat less but still significant Prydz‐Barrier...
Ocean–cryosphere interactions along the Adélie and George V Land (AGVL) coast are investigated using a coupled ocean–sea ice–ice shelf model. The dominant feature of Mertz Glacier Tongue (MGT), located at approximately 145°E, was highly productive winter coastal polynya system, until its calving in February 2010 dramatically changed regional “icescape.” This study examines annual mean, seasonal, interannual variabilities sea ice production; basal melting MGT; shelves, large icebergs, fast...
Observations indicate that vertical diffusivity in the deep ocean is considerably enhanced over rough bathymetry and very small elsewhere. Here we investigate effects of locally bottom topography on world circulation by use a coarse resolution general model. Vertical model, taking into account internal tide breaking. For comparison, two cases an experiment are carried out, where increases with depth without horizontal inhomogeneity. Horizontal distribution upwelling qualitatively different,...
Observed vertical profiles of rare earth elements (REEs) in the North Pacific Ocean show a systematic change from lighter to heavier REEs. Their source and sink consist external fluxes coming surface bottom ocean internal recycling within ocean. In order evaluate role each controlling REEs, we conduct numerical simulations REEs by using an general circulation model. These demonstrate that shape their is not directly related sources river runoff, atmospheric dust deposition, coastal regions...
Abstract The Natal pulses, solitary cyclonic meanders in the Agulhas Current, are reproduced an ocean general circulation model. model covers region around Current with a grid fine enough to reproduce major eddies. features of pulses consistent observational evidences following respects: they generated at Bight when anticyclonic eddies come, move downstream along speeds about 20 km day−1, and grow its horizontal size as move. present simulation shows that generation growth pulse occurs...
Abstract The process of the Pacific water transport in Chukchi Sea and southern Canada Basin is investigated by using an eddy-resolving coupled sea ice–ocean model. simulation result demonstrates that flows into basin mesoscale baroclinic eddies, which are generated developed as a instability narrow intense jet through Barrow Canyon. Each eddy has anticyclonic structure, its horizontal vertical scales grow up being merged with other ones during August September, they separate anticyclones...
The sinking of dense water in the polar oceans plays a key role global thermohaline circulation, leading to heat and material exchange between atmosphere deep ocean. This study provides first surface salt flux dataset for Southern Ocean (including treatment sea ice growth melt), based on calculations satellite-derived data. geographical distribution annual net (salt) shows distinct contrast: significant cooling (salt release into) ocean occurs coastal region, heating (freshwater offshore...
Abstract We investigate spreading pathways of basal meltwater released from all Antarctic ice shelves using a circumpolar coupled shelf‐sea ice‐ocean model that reproduces major features the Southern Ocean circulation, including Circumpolar Current (ACC). Several independent virtual tracers are used to identify detailed meltwaters. The depend on formation sites, because meltwaters transported by local ambient ocean circulation. Meltwaters in Weddell and Amundsen‐Bellingshausen Seas...
The Southern Ocean is of great importance for the global stratification and biological carbon storage because it connected to ocean conveyor by which atmospheric information absorbed in redistributed globally buffered over centuries. Therefore, understanding what controls climate, conveyor, links between them a key quantifying uncertainties future climate projections. Based on set model experiments, here we show that tide-induced micro-scale mixing Pacific deep has significant impacts...