A5022662445- Arctic and Antarctic ice dynamics
- Oceanographic and Atmospheric Processes
- Cryospheric studies and observations
- Climate change and permafrost
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Climate variability and models
- Marine and environmental studies
- Marine and coastal ecosystems
- Ocean Waves and Remote Sensing
- Food Industry and Aquatic Biology
- Polar Research and Ecology
- Ocean Acidification Effects and Responses
- Aquatic and Environmental Studies
- Geological Studies and Exploration
- Oil Spill Detection and Mitigation
- Winter Sports Injuries and Performance
- Marine animal studies overview
- Scientific Research and Discoveries
- Geophysics and Gravity Measurements
- Marine and fisheries research
- Atmospheric and Environmental Gas Dynamics
- Freezing and Crystallization Processes
- Soil Moisture and Remote Sensing
- Arctic and Russian Policy Studies
Hokkaido University
2016-2025
The University of Queensland
2023
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine
2014-2020
National Institute of Polar Research
1998-2015
Hokkaido University of Science
2002-2012
The University of Tokyo
2008
Kyoto University
2005
University of Washington
2004
Japan Meteorological Agency
1998
Active sea‐ice production in Antarctic coastal polynyas causes dense water formation, finally leading to Bottom Water (AABW) formation. This study gives the first mapping of sea ice Ocean, based on heat‐flux calculation with thickness data derived from satellite data. The highest occurs Ross Ice Shelf Polynya region. there decreased by ∼30% 1990s 2000s, which can be one candidate for causing recent freshening AABW. Cape Darnley polynya East Antarctica is found second area, suggesting a...
Abstract Sinking of dense water from Antarctic coastal polynyas produces Bottom Water (AABW), which is the densest in global overturning circulation and a key player climate change as significant sink for heat carbon dioxide. Very recent studies have suggested that landfast sea ice (fast ice) plays an important role formation variability possibly AABW. However, they been limited to regional case investigations only. This study provides first coincident circumpolar mapping fast ice. The map...
Abstract A fourth production region for the globally important Antarctic bottom water has been attributed to dense shelf formation in Cape Darnley Polynya, adjoining Prydz Bay East Antarctica. Here we show new observations from CTD-instrumented elephant seals 2011–2013 that provide first complete assessment of Bay. After a complex evolution involving opposing contributions three polynyas (positive) and two ice shelves (negative), (salinity 34.65–34.7) is exported through Channel. This...
Abstract Enhanced sea ice production (SIP) in Antarctic coastal polynyas forms dense shelf water (DSW), leading to Bottom Water (AABW) formation that ultimately drives the lower limb of meridional overturning circulation. Some studies suggest variability SIP is driven by influence atmospheric forcing, i.e., surface winds and air temperature. Our previous mapping 13 major from 1992 2007, using a heat flux calculation with thickness data derived satellite data, extended here examine...
High ice production in coastal polynyas over the continental shelves Arctic Ocean is responsible for formation of cold saline water, which contributes to maintenance halocline. The accurate detection polynyas, including an estimate thin thickness, essential estimation sea production. This paper presents algorithm that estimates thickness using Special Sensor Microwave/Imager (SSM/I) data Ocean. Detection and thicknesses <0.15 m are based on SSM/I 85 37 GHz polarization ratios (PR PR )...
Ice-albedo feedback due to the albedo contrast between water and ice is a major factor in seasonal sea retreat, has received increasing attention with Arctic Ocean shifting cover. However, quantitative evaluation of such feedbacks still insufficient. Here we provide evidence that heat input through open fraction primary driver interannual variations retreat. Analyses satellite data (1979-2014) simplified ice-upper ocean coupled model reveal divergent motion early melt season triggers...
Global overturning circulation is driven by density differences. Saline water rejected during sea-ice formation in polynyas the main source of dense water, and thus production a key factor circulation. Due to difficulties associated with situ observation, its interannual variability have not been well understood until recently. Methods estimate on large scales developed using heat flux calculations based satellite microwave radiometer data. Using these methods, we present mapping same...
Abstract The importance of the area active frazil and associated high sea‐ice production in Antarctic coastal polynyas has been increasingly recognized recent situ high‐resolution satellite observations. However, occurrence spatial distribution active‐frazil are not well understood. We present first mapping for polynyas, based on thin ice algorithm AMSR‐E that discriminates area. Mapping is presented by taking account Active‐frazil predominant along East Antarctica, particularly very close...
Near‐surface circulation of the Okhotsk Sea was observed with ARGOS drifters from August 1999 to February 2000. The clearly revealed existence southward boundary current (the East Sakhalin Current) off east Sakhalin. This is strongly controlled by bottom topography and confined region shallower than 1000 m. volume transport this estimated be in range 4–9 Sv (1 = 10 6 m 3 s −1 ), increase summer winter. appears consist two cores: one exists near coast (50–150 depths) typical speeds 0.3–0.4...
Abstract Antarctic coastal polynyas are important areas of high sea ice production and dense water formation, thus their detection including an estimate thin thickness is essential. In this paper, the authors propose algorithm that estimates detects fast using Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I) data in Ocean. Detection estimation thicknesses &lt;0.2 m based on SSM/I 85- 37-GHz polarization ratios (PR85 PR37) through a comparison with...
On the basis of all available data, it is found that intermediate water temperature on 26.8–27.4 σ θ isopycnals in northwestern North Pacific has significantly increased during past 50 years. The largest warming area exists western part Sea Okhotsk with a 0.68°C/50‐yr increase observed at 27.0 . over Oyashio and Subarctic Current regions, where extends along subarctic gyre. This suggests originates from Okhotsk. trend also accompanied by significant decreasing dissolved oxygen content,...
Variability in dense shelf water formation can potentially impact Antarctic Bottom Water (AABW) production, a vital component of the global climate system. In East Antarctica, George V Land polynya system (142–150°E) is structured by local 'icescape', promoting sea ice that driven offshore wind regime. Here we present first observations this region after repositioning large iceberg (B9B) precipitated calving Mertz Glacier Tongue 2010. Using satellite data, find total production for 2010 and...
Abstract New and improved estimates of sea ice production in the Arctic Ocean are derived from AMSR‐E satellite atmospheric reanalysis data for period 2002–2011, at a spatial resolution 6.25 km using newly developed fast‐ice mask. High major coastal polynyas is well demonstrated. The total annual cumulative 10 polynya regions about . interannual variability each presented during 2002–2011. No obvious relationship noted between recent drastic reduction preceding summer extent. Most exhibit...
Antarctic coastal polynyas are very high sea-ice production areas. The resultant large amount of brine rejection leads to the formation dense water. water forms bottom water, which is densest in global overturning circulation and a key player climate change as significant sink for heat carbon dioxide. In this study, an algorithm was developed that uses Advanced Microwave Scanning Radiometer 2 (AMSR2) data (2012–present) detect polynya area estimates thin ice thickness by method similar used...
Abstract. Landfast sea ice (fast ice) is an important component of the Antarctic nearshore marine environment, where it strongly modulates sheet–ocean–atmosphere interactions and biological biogeochemical processes, forms a key habitat, affects logistical operations. Given wide-ranging importance fast its sensitivity to climate change, improved knowledge change variability in distribution high priority. fast-ice mapping date has been limited regional studies time series covering East...
Abstract. Landfast sea ice (fast ice) is an important though poorly understood component of the cryosphere on Antarctic continental shelf, where it plays a key role in atmosphere–ocean–ice-sheet interaction and coupled ecological biogeochemical processes. Here, we present first in-depth baseline analysis variability change circum-Antarctic fast-ice distribution (including its relationship to bathymetry), based new high-resolution satellite-derived time series for period 2000 2018. This...
The Totten Glacier in East Antarctica, with an ice volume equivalent to >3.5 m of global sea-level rise, is grounded below sea level and, therefore, vulnerable ocean forcing. Here, we use bathymetric and oceanographic observations from previously unsampled parts the continental shelf reveal on-shelf warm water pathways defined by deep topographic features. Access Ice Shelf (TIS) cavity facilitated a break, broad depression on shelf, cyclonic circulation that carries inner troughs provide...
Dense, cold waters formed on Antarctic continental shelves descend along the margin, where they mix with other Southern Ocean to form Bottom Water (AABW). AABW then spreads into deepest parts of all major ocean basins, isolating heat and carbon from atmosphere for centuries. Despite AABW’s key role in regulating Earth’s climate long time scales recording conditions, remains poorly observed. This lack observational data is mostly due two factors. First, originates shelf slope situ...
In order to clarify the distribution and formation of Okhotsk Sea Intermediate Water (OSIW) an isopycnal climatological data set based on all available historical observations is developed examined. The maps clearly show that there are two direct ventilation sources for OSIW: Dense Shelf (DSW) with cold fresh properties influenced by sea ice in northwest shelf region Forerunner Soya Warm Current (FSCW), which has warm saline originating Japan Sea. water extends southward from slope off...
We investigate how the current system through Japan Sea is driven and what determines volume transport. suppose that a part of difference in geopotential anomaly between subtropical subpolar gyre converted into barotropic sea level across three shallow straits which connect with Pacific this primary driving force system. Then, we examine flow under condition there constant two oceans connected strait. found strait acts as source arrested shelf waves or steady coastal flows for timescale...
The third FRONT (F‐region Radio and Optical measurement of Nighttime TID) campaign was carried out during the new‐moon period May–June 2003, in order to investigate geomagnetic conjugacy medium‐scale large‐scale traveling ionospheric disturbances (MSTIDs/LSTIDs) at midlatitudes. Seven all‐sky airglow imagers were operated Japan Australia. For almost all clear‐sky nights, we observed MSTIDs 630‐nm images with horizontal wavelengths 100–400 km propagating southwestward northwestward All them...
From comparisons with thickness of sea ice from Advanced Very High Resolution Radiometer (AVHRR) and ice‐profiling sonar data we have developed an Microwave Scanning Radiometer‐EOS (AMSR‐E) thin algorithm for the Sea Okhotsk. This can estimate ≤0.2 m without snow using polarization ratio AMSR‐E brightness temperature at a 36.5 GHz channel linear relationship AVHRR thickness. When cover exists on surface, as occurred few times in each winter, it is shown that cannot detect ice. dense shelf...
Over the past few decades, sea ice retreat during summer has been enhanced in Pacific sector of Arctic basin, likely due part to increasing summertime heat flux Pacific-origin water from Bering Strait. Barrow Canyon, northeast Chukchi Sea, is a major conduit through which enters basin. This paper presents results 6 repeat high-resolution shipboard hydrographic/velocity sections occupied across Canyon 2010. The different masses feeding canyon – Alaskan coastal (ACW), Sea (BSW), and winter...