The foundations of the Patagonian icefields
Johannes J. Fürst, David Farías-Barahona, Norbert Blindow, Gino Casassa, Guisella Gacitúa, Michèle Koppes, Emanuele Lodolo, Romain Millan, Masahiro Minowa, Jérémie Mouginot, Michał Pȩtlicki, Eric Rignot, Andres Rivera, Pedro Skvarca, Martin Stuefer, Shin Sugiyama, José Uribe, Rodrigo Zamora, Matthias H. Braun, Fabien Gillet-Chaulet, Philipp Malz, Wolfgang J.-H. Meier, Marius Schaefer
Communications Earth & Environment, 5, 1, Springer Science and Business Media LLC, 22 Mar. 2024
Scientific journal, Abstract

The two vast Patagonian icefields are a global hotspot for ice-loss. However, not much is known about the total ice volume they store - let alone its spatial distribution. One reason is that the abundant record of direct thickness measurements has never been systematically exploited. Here, this record is combined with remotely-sensed information on past ice thickness mapped from glacier retreat. Both datasets are incorporated in a state-of-the-art, mass-conservation approach to produce a well-informed map of the basal topography beneath the icefields. Its major asset is the reliability increase of thicknesses values along the many marine- and lake-terminating glaciers. For these, frontal ice-discharge is notably lower than previously reported. This finding implies that direct climatic control was more influential for past ice loss. We redact a total volume for both icefields in 2000 of 5351 km³. Despite the wealth of observations used in this assessment, relative volume uncertainties remain elevated.

Foehn winds influence surface ablation on Glaciar Perito Moreno, Southern Patagonian Icefield
Masahiro Minowa, Pedro Skvarca, Koji Fujita
Journal of Glaciology, 1, 33, Cambridge University Press (CUP), 04 Jan. 2024, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

SE‐Dome II Ice Core Dating With Half‐Year Precision: Increasing Melting Events From 1799 to 2020 in Southeastern Greenland
Kaoru Kawakami, Yoshinori Iizuka, Mahiro Sasage, Mai Matsumoto, Takeshi Saito, Akira Hori, Sakiko Ishino, Shuji Fujita, Koji Fujita, Keita Takasugi, Takumi Hatakeyama, Saaya Hamamoto, Akihisa Watari, Nao Esashi, Miu Otsuka, Ryu Uemura, Kazuho Horiuchi, Masahiro Minowa, Shohei Hattori, Teruo Aoki, Motohiro Hirabayashi, Kenji Kawamura, Sumito Matoba
Journal of Geophysical Research: Atmospheres, 128, 20, American Geophysical Union (AGU), 13 Oct. 2023, [Peer-reviewed]
Scientific journal, Abstract

Arctic warming has accelerated surface melting even in the highland areas of the Greenland ice sheet (GrIS). Understanding the relationship between climate and surface melting is essential for improving the estimates of ice‐sheet mass loss due to warming. Here we analyze a 250 m‐long ice core from the southeastern dome of GrIS (SE‐Dome site; 67°19′17″ N, 36°47′03″ W, 3,161 m a.s.l.), where the annual mean temperature is −20.9°C and the accumulation rate is high and there is a large discrepancy among climate models regarding snow accumulation estimates. A time scale was established for 1799–2020 with a half‐year uncertainty using annual counting of H₂O₂ concentration and five time horizons determined by electrical conductivity, melt events, and tritium concentration. The annual accumulation rate from the ice core shows no significant trend over 221 years and has an average of 1.04 ± 0.20 m w.e. year⁻¹. In contrast, the frequency and thickness of refrozen melt layer (ML) have increased over 221 years, and are synchronized with temperature changes in the Arctic. The thickness of MLs correlates positively with the time‐integrated summer temperature anomaly using a reanalysis of air temperature. The in‐situ accumulation records in the southeastern GrIS provide an important basis for correcting reanalysis data such as ERA5, which in turn are valuable for improving regional climate models.

Tidal and thermal stresses drive fracture of the ice shelf of Langhovde Glacier, East Antarctica
箕輪昌紘, Evgeny Podolskiy, 杉山慎
Annual Report on Snow and Ice Studies in Hokkaido, 42, Sep. 2023, [Lead author, Corresponding author]
Japanese, 36786495

Effects of topography on dynamics and mass loss of lake-terminating glaciers in southern Patagonia
Masahiro Minowa, Marius Schaefer, Pedro Skvarca
Journal of Glaciology, 1, 18, Cambridge University Press ({CUP}), 11 Jul. 2023, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal, Abstract
Calving glaciers are highly sensitive to bedrock geometry near their terminus. To understand the mechanisms controlling rapid calving glaciers’ mass loss, we measured the lake topography in front of four lake-terminating glaciers in the southern Patagonian icefield. Using remotely sensed surface elevation data, we calculated flotation height and surface slope and compared those with changes in ice-front position, surface speed and surface elevation. Rapid retreat accompanied by rapid flow acceleration and ice surface steepening was observed at Glaciar Upsala from 2008–2011, and at O'Higgins and Viedma glaciers from 2016–present. Surface lowering in the lower part of Glaciar Upsala reached 30 m a−1 and was 18 m a−1 and 12 m a−1 at O'Higgins and Viedma glaciers, respectively. Near- or super-buoyant conditions were observed prior to these events, leading to gradual flow acceleration due to low effective pressure and decoupling from the bed. The super-buoyant condition and gradual acceleration imply full-thickness buoyant calving, which causes the ice front to retreat from the shallow bedrock topography with substantial flow acceleration. We conclude that the buoyancy force plays an important role in the rapid mass loss of lake-terminating glaciers in southern Patagonia., 36786495

Climate and Surface Mass Balance at Glaciar Perito Moreno, Southern Patagonia
Masahiro Minowa, Pedro Skvarca, Koji Fujita
Journal of Climate, 36, 2, 625, 641, American Meteorological Society, 15 Jan. 2023, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal, Abstract

The mass budget of southern Patagonian glaciers is characterized by an extreme amount of surface ablation. To understand the processes controlling surface mass balance, we analyzed in situ data including meteorological variables and ablation stakes for the 25 years between 1996 and 2020 near the terminus of Glaciar Perito Moreno in southern Patagonia in South America. The mean annual temperature has increased over the study period at a rate of 0.2°C decade⁻¹. An energy-balance model was applied to calculate a point surface mass balance, based on meteorological records. The average point surface mass balance is estimated to be −16.3 m water equivalent (w.e.) yr⁻¹ between 1996 and 2020, decreasing at a rate in the range from −0.4 to −0.9 m w.e. yr⁻¹ decade⁻¹. The greatest contribution to the surface energy balance was due to the sensible heat flux, and its variation drove the surface mass balance variation. The meteorological and surface mass balance records were compared with the Southern Annular Mode and El Niño–Southern Oscillation, which change the atmospheric circulation over southern Patagonia and influence surface mass balance near the terminus of the glacier. Our long-term dataset investigates the detailed meteorological conditions and surface mass balance and their connection with the large-scale climate variability over the last 25 years, reported for the first time in Patagonia., 34345681

利尻島ヤムナイ沢雪渓における 2021 年現地調査報告　　　　　　　　　　　　　　　
波多 俊太郎, 杉山 慎, 箕輪 昌紘, 日下 稜, 近藤 研, Wang Yefa, 渡邊 果歩
北海道の雪氷, 41, 39, 42, 2022
Japanese

東南極ラングホブデ氷河における底面滑りの直接観測　　　　　　　　　　　　　　　
近藤 研, 杉山 慎, 箕輪 昌紘
北海道の雪氷, 41, 35, 38, 2022
Japanese

南極ラングホブデ氷河における 2021/22 年の熱水掘削　　　　　　　　　　　　　　　
杉山 慎, 近藤 研, 箕輪 昌紘
北海道の雪氷, 41, 31, 34, 2022
Japanese, Symposium

Subglacial discharge controls seasonal variations in the thermal structure of a glacial lake in Patagonia
Shin Sugiyama, Masahiro Minowa, Yasushi Fukamachi, Shuntaro Hata, Yoshihiro Yamamoto, Tobias Sauter, Christoph Schneider, Marius Schaefer
Nature Communications, 12, 1, Springer Science and Business Media {LLC}, Dec. 2021, [Peer-reviewed]
English, Scientific journal, AbstractWater temperature in glacial lakes affects underwater melting and calving of glaciers terminating in lakes. Despite its importance, seasonal lake temperature variations are poorly understood because taking long-term measurements near the front of calving glaciers is challenging. To investigate the thermal structure and its seasonal variations, we performed year-around temperature and current measurement at depths of 58–392 m in Lago Grey, a 410-m-deep glacial lake in Patagonia. The measurement revealed critical impacts of subglacial discharge on the lake thermal condition. Water below a depth of ~100 m showed the coldest temperature in mid-summer, under the influence of glacial discharge, whereas temperature in the upper layer followed a seasonal variation of air temperature. The boundary of the lower and upper layers was controlled by the depth of a sill which blocks outflow of dense and cold glacial meltwater. Our data implies that subglacial discharge and bathymetry dictate mass loss and the retreat of lake-terminating glaciers. The cold lakewater hinders underwater melting and facilitates formation of a floating terminus.

Ice core drilling and the related observations at the SE-Dome site, southeastern Greenland Ice Sheet
Y. Iizuka, S. Matoba, M. Minowa, T. Yamasaki, K. Kawakami, A. Kakugo, M. Miyahara, K. Fujita, A. Hashimoto, M. Niwano, T. Tanikawa, T. Aoki
Bulletin of Glaciological Research, 39, 1, 12, Japanese Society of Snow and Ice, Oct. 2021, [Peer-reviewed]
English, Scientific journal

Thermohaline structure and circulation beneath the Langhovde Glacier ice shelf in East Antarctica
Masahiro Minowa, Shin Sugiyama, Masato Ito, Shiori Yamane, Shigeru Aoki
NATURE COMMUNICATIONS, 12, 1, NATURE PORTFOLIO, Jul. 2021, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal, Basal melting of ice shelves is considered to be the principal driver of recent ice mass loss in Antarctica. Nevertheless, in-situ oceanic data covering the extensive areas of a subshelf cavity are sparse. Here we show comprehensive structures of temperature, salinity and current measured in January 2018 through four boreholes drilled at a similar to 3-km-long ice shelf of Langhovde Glacier in East Antarctica. The measurements were performed in 302-12m-thick ocean cavity beneath 234-412m-thick ice shelf. The data indicate that Modified Warm Deep Water is transported into the grounding zone beneath a stratified buoyant plume. Water at the ice-ocean interface was warmer than the in-situ freezing point by 0.65-0.95 degrees C, leading to a mean basal melt rate estimate of 1.42ma(-1). Our measurements indicate the existence of a density-driven water circulation in the cavity beneath the ice shelf of Langhovde Glacier, similar to that proposed for warm-ocean cavities of larger Antarctic ice shelves. Basal melting of ice shelves is the principal driver of recent ice mass loss in Antarctica. The study reports comprehensive structures of temperature, salinity and current under an ice shelf in East Antarctica obtained by borehole measurements.

Variations in mineralogy of dust in an ice core obtained from northwestern Greenland over the past 100 years
Naoko Nagatsuka, Kumiko Goto-Azuma, Akane Tsushima, Koji Fujita, Sumito Matoba, Yukihiko Onuma, Remi Dallmayr, Moe Kadota, Motohiro Hirabayashi, Jun Ogata, Yoshimi Ogawa-Tsukagawa, Kyotaro Kitamura, Masahiro Minowa, Yuki Komuro, Hideaki Motoyama, Teruo Aoki
CLIMATE OF THE PAST, 17, 3, 1341, 1362, COPERNICUS GESELLSCHAFT MBH, Jun. 2021, [Peer-reviewed]
English, Scientific journal, Our study is the first to demonstrate a high-temporal-resolution record of mineral composition in a Greenland ice core over the past 100 years. To reconstruct past variations in the sources and transportation processes of mineral dust in northwestern Greenland, we analysed the morphology and mineralogical composition of dust in the SIGMA-D ice core from 1915 to 2013 using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results revealed that the ice core dust consisted mainly of silicate minerals and that the composition varied substantially on multi-decadal and inter-decadal scales, suggesting that the ice core minerals originated from different geological sources in different periods during the past 100 years. The multi-decadal variation trend differed among mineral types. Kaolinite, which generally formed in warm and humid climatic zones, was abundant in colder periods (1950-2004), whereas mica, chlorite, feldspars, mafic minerals, and quartz, which formed in arid, high-latitude, and local areas, were abundant in warmer periods (1915-1949 and 2005-2013). Comparison to Greenland surface temperature records indicates that multi-decadal variation in the relative abundance of these minerals was likely affected by local temperature changes in Greenland. Trajectory analysis shows that the minerals were transported mainly from the western coast of Greenland in the two warming periods, which was likely due to an increase in dust sourced from local icefree areas as a result of shorter snow/ice cover duration in the Greenland coastal region during the melt season caused by recent warming. Meanwhile, ancient deposits in northern Canada, which were formed in past warmer climates, seem to be the best candidate during the colder period (1950-2004). Our results suggest that SEM-EDS analysis can detect variations in ice core dust sources during recent periods of low dust concentration.

Frontal ablation and mass loss of the Patagonian icefields
Masahiro Minowa, Marius Schaefer, Shin Sugiyama, Daiki Sakakibara, Pedro Skvarca
EARTH AND PLANETARY SCIENCE LETTERS, 561, ELSEVIER, May 2021, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal, The complex dynamics of calving glaciers is a major uncertainty in projecting global glacial mass loss. We present frontal ablation and ice mass change for the 38 major calving glaciers in the Patagonian icefields based on remote-sensing observations of ice-front positions, surface speeds and elevation changes. The frontal ablation from 2000 to 2019 was -24.1 +/- 1.7 Gt a(-1), which represents 34 +/- 6% of the total ablation of the icefields. The fraction of frontal ablation was close to half in the southern icefield and about one fifth in the northern icefield. The rate of the mass loss from the icefields during the period of study was 15.2 +/- 3.5 Gt a(-1), which is generally explained by surface mass balance but was accelerated as a result of increasing frontal ablation. The frontal ablation and mass change values suggest surface mass balance to be -1.5 +/- 0.9 Gt a(-1) for the northern icefield and +11.5 +/- 2.7 Gt a(-1) for the southern icefield during this period. Our study demonstrates that a strong increase in frontal ablation at several glaciers drives the mass loss in the southern icefield, whereas increasingly negative surface mass balance drives the mass loss in the northern icefield. (C) 2021 Elsevier B.V. All rights reserved.

Rapidly changing glaciers, ocean and coastal environments, and their impact on human society in the Qaanaaq region, northwestern Greenland
Shin Sugiyama, Naoya Kanna, Daiki Sakakibara, Takuto Ando, Izumi Asaji, Ken Kondo, Yefan Wang, Yoshiki Fujishi, Shungo Fukumoto, Evgeniy Podolskiy, Yasushi Fukamachi, Minori Takahashi, Sumito Matoba, Yoshinori Iizuka, Ralf Greve, Masato Furuya, Kazutaka Tateyama, Tatsuya Watanabe, Shintaro Yamasaki, Atsushi Yamaguchi, Bungo Nishizawa, Kohei Matsuno, Daiki Nomura, Yuta Sakuragi, Yoshimasa Matsumura, Yoshihiko Ohashi, Teruo Aoki, Masashi Niwano, Naotaka Hayashi, Masahiro Minowa, Guillaume Jouvet, Eef van Dongen, Andreas Bauder, Martin Funk, Anders Anker Bjork, Toku Oshima
POLAR SCIENCE, 27, ELSEVIER, Mar. 2021, [Peer-reviewed]
English, Scientific journal, Environments along the coast of Greenland are rapidly changing under the influence of a warming climate in the Arctic. To better understand the changes in the coastal environments, we performed researches in the Qaanaaq region in northwestern Greenland as a part of the ArCS (Arctic Challenge for Sustainability) Project. Mass loss of ice caps and marine-terminating outlet glaciers were quantified by field and satellite observations. Measurements and sampling in fjords revealed the important role of glacial meltwater discharge in marine ecosystems. Flooding of a glacial stream in Qaanaaq and landslides in a nearby settlement were investigated to identify the drivers of the incidents. Our study observed rapid changes in the coastal environments, and their critical impact on the society in Qaanaaq. We organized workshops with the residents to absorb local and indigenous knowledge, as well as to share the results and data obtained in the project. Continuous effort towards obtaining long-term observations requiring involvement of local communities is crucial to contribute to a sustainable future in Greenland.

Tide-modulated ice motion and seismicity of a floating glacier tongue in East Antarctica
Masahiro Minowa, Evgeny A. Podolskiy, Shin Sugiyama
ANNALS OF GLACIOLOGY, 60, 79, 57, 67, CAMBRIDGE UNIV PRESS, Sep. 2019, [Peer-reviewed], [Lead author]
English, Scientific journal, We recorded the ice motion and icequakes on the floating part of Langhovde Glacier in East Antarctica to better understand the dynamic behavior of ice shelves and floating tongues. Diurnal and semi-diurnal variations in ice motion and seismicity were simultaneously observed at all four global navigation satellite system and three seismic stations over 2 weeks. The short-term along-flow ice motion is explained by the elastic response of the glacier to ocean tide-induced hydrostatic stress variations, which decayed at a rate of 0.8 km(-1) toward the grounding line. We observed a large number of icequakes during mid-rising and high tides that covered a broad frequency range and formed two major groups of events centered at 10 and 120 Hz, respectively. The hourly occurrence rates were similar to 500 events h(-1), with the observed seismicity consistent with fracture due to floating tongue bending. We also observed minor secondary peaks at high ice speeds, which could reflect surface cracking due to stretching or basal friction. Our observation demonstrates that tidal-modulation was the main factor to fracture the floating tongue of Langhovde Glacier.

Subglacial water pressure and ice-speed variations at Johnsons Glacier, Livingston Island, Antarctic Peninsula
Shin Sugiyama, Francisco J. Navarro, Takanobu Sawagaki, Masahiro Minowa, Takahiro Segawa, Yukihiko Onuma, Jaime Otero, Evgeny V. Vasilenko
JOURNAL OF GLACIOLOGY, 65, 252, 689, 699, CAMBRIDGE UNIV PRESS, Aug. 2019, [Peer-reviewed]
English, Scientific journal, To study subglacial hydrological condition and its influence on the glacier dynamics, we drilled Johnsons Glacier on Livingston Island in the Antarctic Peninsula region. Subglacial water pressure was recorded in boreholes at two locations over 2 years, accompanied by high-frequency ice-speed measurements during two summer melt seasons. Water pressure showed two different regimes, namely high frequency and large amplitude variations during the melt season (January-April) and small fluctuations near the overburden pressure the rest of the year. Speed-up events were observed several times in each summer measurement period. Ice motion during these events substantially contributed to total glacier motion, for example, fast ice flow over 1 week accounted for similar to 70% of the total displacement over a 25-day long measurement period. We did not find a clear relationship between subglacial water pressure and ice speed. This was probably because subglacial hydraulic conditions were spatially inhomogeneous and thus our borehole data did not always represent a large-scale subglacial condition. Ice temperature measurements in the boreholes confirmed the existence of a cold ice layer near the glacier surface. Our data provide a basis to better understand the dynamic and hydrological conditions of relatively unstudied glaciers in the Antarctic Peninsula region.

Calving flux estimation from tsunami waves
Masahiro Minowa, Evgeny A. Podolskiy, Guillaume Jouvet, Yvo Weidmann, Daiki Sakakibara, Shun Tsutaki, Riccardo Genco, Shin Sugiyama
EARTH AND PLANETARY SCIENCE LETTERS, 515, 283, 290, ELSEVIER, Jun. 2019, [Peer-reviewed], [Lead author]
English, Scientific journal, Measuring glacier calving magnitude, frequency and location in high temporal resolution is necessary to understand mass loss mechanisms of ocean-terminating glaciers. We utilized calving-generated tsunami signals recorded with a pressure sensor for estimating the calving flux of Bowdoin Glacier in northwestern Greenland. We find a relationship between calving ice volume and wave amplitude. This relationship was used to compute calving flux variation. The calving flux showed large spatial and temporal fluctuations in July 2015 and in July 2016, with a mean flux of 2.3 +/- 0.15 x 10(5) m(3) d(-1). Calving flux was greater during periods of fast ice flow, high air temperature, and at low/falling tide, indicating the importance of increased longitudinal strain due to glacier acceleration and/or submarine melting at the calving front. Long-term measurements with the method introduced here are promising for understanding the complex interplay of ice dynamics, melting and calving at glacier fronts. (C) 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Response of the flow dynamics of Bowdoin Glacier, northwestern Greenland, to basal lubrication and tidal forcing
Hakime Seddik, Ralf Greve, Daiki Sakakibara, Shun Tsutaki, Masahiro Minowa, Shin Sugiyama
JOURNAL OF GLACIOLOGY, 65, 250, 225, 238, CAMBRIDGE UNIV PRESS, Apr. 2019, [Peer-reviewed]
English, Scientific journal, We use the full-Stokes model Elmer/Ice to investigate the present dynamics of Bowdoin Glacier, a marine-terminating outlet glacier in northwestern Greenland. Short-term speed variations of the glacier were observed, correlating with air temperature and precipitation, and with the semi-diurnal ocean tides. We use a control inverse method to determine the distribution of basal friction. This reveals that most of the glacier area is characterized by near-plug-flow conditions, while some sticky spots are also identified. We then conduct experiments to test the sensitivity of the glacier flow to basal lubrication and tidal forcing at the calving front. Reduction of the basal drag by 10-40% produces speed-ups that agree approximately with the observed range of speed-ups that result from warm weather and precipitation events. In agreement with the observations, tidal forcing and surface speed near the calving front are found to be in anti-phase (high tide corresponds to low speed, and vice versa). However, the amplitude of the semi-diurnal variability is underpredicted by a factor similar to 3, which is likely related to either inaccuracies in the surface and bedrock topographies or mechanical weakening due to crevassing.

Underwater Ice Terrace Observed at the Front of Glaciar Grey, a Freshwater Calving Glacier in Patagonia
Shin Sugiyama, Masahiro Minowa, Marius Schaefer
GEOPHYSICAL RESEARCH LETTERS, 46, 5, 2602, 2609, AMER GEOPHYSICAL UNION, Mar. 2019, [Peer-reviewed]
English, Scientific journal, Underwater ice geometry at the front of calving glaciers provides crucial information for calving and underwater melting. In this study, we present ice geometry captured by operating a side-scanning sonar near the front of Glaciar Grey, a freshwater calving glacier in Patagonia. The observations revealed ice projecting into the lake with a substantially different structure from that of known tidewater glaciers. Terrace-like ice structures were found at several tens of meters below the water surface and extended up to 100m from the aerial ice front. The structure depicted by the sonar was confirmed when the ice front was exposed by flotation during a major calving event. We infer that buoyant force acting on the submerged ice terrace acted as a driver of the calving event. Our study demonstrates the importance of the underwater ice geometry, which affects sizable calving at the front of freshwater calving glaciers.Plain Language Summary Glaciers terminating in lakes and the ocean are in general retreating more rapidly than glaciers on land. This is because such glaciers lose ice by discharging icebergs and melting in water. The shape of the submerged part of the ice front provides important information for understanding iceberg production and melting, but measurements near the glacier front are difficult to obtain. In this study, we used a side-scanning sonar to visualize underwater ice of a lake terminating glacier in Patagonia. The observations revealed ice jutting into the lake, forming terrace-like structures several tens of meters below the water surface. The structure was significantly different from that of ocean terminating glaciers. The observation was confirmed when the ice front was detached from the glacier and exposed by flotation. Our study demonstrates that buoyant force acting on the ice terrace plays a key role in the production of large icebergs at the front of freshwater calving glaciers.

Glaciological traverse across the Southern Patagonian Icefield
Masahiro Minowa, Marius Schaefer, Pedro Skvarca, Sumito Matoba, GuiseIla Gacitua
BULLETIN OF GLACIOLOGICAL RESEARCH, 37, 47, 56, NIHON SEPPYO GAKKAI-JAPANESE SOC SNOW & ICE, 2019, [Peer-reviewed], [Lead author]
English, Scientific journal, To better understand the temporal variation of the ice surface elevation and the spatio-temporal variation of snow accumulation in the accumulation area of the Southern Patagonian Icefield, we carried out a glaciological traverse in October 2018. This included measurements of surface elevation, firn layers, and sampling of snow in the accumulation areas of Glaciar Viedma and Glaciar Pio XI. The main results from the traverse are: i) during the period of 2000-2018 the surface elevation in the accumulation area of Glaciar Viedma decreased by 1.7 m a(-1), but increased at Glaciar Pio XI by 0.4 m a(-1), ii) ground-penetrating radar revealed numerous firn layers with a continuous water aquifer at 20-40 m depth, iii) the water isotope ratio of surface snow samples varied with wind direction. Repeating the traverse in the area will provide an opportunity to answer questions about the contrasting glacier behavior and the snow accumulation rate, a necessary step to make reliable projections of future glacier behavior in Patagonia.

Glacier calving observed with time-lapse imagery and tsunami waves at Glaciar Perito Moreno, Patagonia
Masahiro Minowa, Evgeny A. Podolskiy, Shin Sugiyama, Daiki Sakakibara, Pedro Skvarca
JOURNAL OF GLACIOLOGY, 64, 245, 362, 376, CAMBRIDGE UNIV PRESS, Jun. 2018, [Peer-reviewed], [Lead author]
English, Scientific journal, Calving plays a key role in the recent rapid retreat of glaciers around the world. However, many processes related to calving are poorly understood since direct observations are scarce and challenging to obtain. When calving occurs at a glacier front, surface-water waves arise over the ocean or a lake in front of glaciers. To study calving processes from these surface waves, we performed field observations at Glaciar Perito Moreno, Patagonia. We synchronized time-lapse photography and surface waves record to confirm that glacier calving produces distinct waves compared with local noise. A total of 1074 calving events were observed over the course of 39 d. During austral summer, calving occurred twice more frequently than in spring. The cumulative distribution of calving-interevent time interval followed exponential model, implying random occurrence of events in time. We further investigated wave properties and found that source-to-sensor distance can be estimated from wave dispersion within similar to 20% error. We also found that waves produced by different calving types showed similar spectra in the same frequency range between 0.05-0.2 Hz, and that the amplitude of surface waves increased with the size of calving. This study demonstrates the potential of surface-wave monitoring for understanding calving processes.

Variations in mineralogy of dust in ice core obtained from Northwestern Greenland Ice Sheet
Nagatsuka Naoko, Goto-Azuma Kumiko, Tsushima Akane, Motoyama Hideaki, Matoba Sumito, Fujita Koji, Yamasaki Tetsuhide, Onuma Yukihiko, Minowa Masahiro, Aoki Teruo
Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 119, 119, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
Japanese

Seismic and infrasound monitoring of Bowdoin Glacier, Greenland
Podolskiy Evgeny A., Genco Riccardo, Sugiyama Shin, Walter Fabian, Funk Martin, Minowa Masahiro, Tsutaki Shun, Ripepe Maurizio
低温科学, 75, 15, 36, 低温科学第75巻編集委員会, 2017
English, Outlet glaciers in Greenland have retreated and lost mass over the past decade. Understandingthe dynamics of tidewater glaciers is crucial for forecasting sea-level rise and for understanding thefuture of the Greenland Ice Sheet, given the buttressing support that tidewater glaciers provide toinland ice. However, the mechanisms controlling glacier-front location and the role played byexternal forcings (e.g., meltwater input and tidal oscillation) in basal motion and fracture formationleading to iceberg calving are poorly understood. Today it is known that glaciers generate seismicand infrasound signals that are detectable at local and teleseismic distances and can be used to monitorglacier dynamics. Here, we present examples of data recorded by a temporary network of seismicand infrasound instruments deployed at a tidewater glacier (Bowdoin Glacier, Greenland) in July 2015.Some stations were installed on ice at distances as close as ～ 250 m from the calving front,representing the closest deployments to the calving front that have been made to date. Multipleseismic and infrasound events were recorded by five seismic and six infrasound sensors, and linked tosurface crevassing, calving, and ice-cliff collapses, and presumably also hydrofracturing, icebergrotations, teleseismic earthquakes, and helicopter-induced tremors. Using classic seismological andarray analysis approaches (e.g., "short-term averaging/long-term averaging" and "f-k" analysis), as wellas image processing techniques, we explore this unique dataset to understand the glacial response toexternal forcings. Our observations, supported by GPS measurements of ice velocity, local weatherstationrecords, and time-lapse photography, provide a valuable resource for studying seismogenicglacial processes and their dependence on ocean tides and other environmental factors.

Seasonal Variations in Ice-Front Position Controlled by Frontal Ablation at Glaciar Perito Moreno, the Southern Patagonia Icefield
Masahiro Minowa, Shin Sugiyama, Daiki Sakakibara, Pedro Skvarca
FRONTIERS IN EARTH SCIENCE, 5, FRONTIERS MEDIA SA, Jan. 2017, [Peer-reviewed], [Lead author]
English, Scientific journal, The front position of calving glaciers is controlled by ice speed and frontal ablation which consists of the two processes of calving and subaqueous melting. However, the relative importance of these processes in frontal variation is difficult to assess and poorly understood, particularly for freshwater calving glaciers. To better understand the mechanism of seasonal variations involved in the ice front variations of freshwater calving glaciers, we measured front position, ice surface speed, air temperature, and proglacial lakewater temperature of Glaciar Perito Moreno in Patagonia. No substantial fluctuations in front position and ice speed occurred during the 15-year period studied (1999-2013), despite a warming trend in air temperature (0.059 degrees C a(-1)). Seasonal variations were observed both in the ice-front position (+/- 50 m) and ice speed (+/- 15%). The frontal ablation rate, computed from the frontal displacement rate and the ice speed, varied in a seasonal manner with an amplitude approximately five times greater than that in the ice speed. The frontal ablation correlated well with seasonal lakewater temperature variations (r = 0.96) rather than with air temperature (r = 0.86). Our findings indicate that the seasonal ice front variations of Glaciar Perito Moreno are primarily due to frontal ablation, which is controlled through subaqueous melting by the thermal conditions of the lake.

Thermal structure of proglacial lakes in Patagonia
Shin Sugiyama, Masahiro Minowa, Daiki Sakakibara, Pedro Skvarca, Takanobu Sawagaki, Yoshihiko Ohashi, Nozomu Naito, Kazuhisa Chikita
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE, 121, 12, 2270, 2286, AMER GEOPHYSICAL UNION, Dec. 2016, [Peer-reviewed]
English, Scientific journal, Calving glaciers are rapidly retreating in many regions under the influence of ice-water interactions at the glacier front. In contrast to the numerous researches conducted on fjords in front of tidewater glaciers, very few studies have been reported on lakes in which freshwater calving glaciers terminate. To better understand ice-water interactions at the front of freshwater calving glaciers, we measured lakewater temperature, turbidity, and bathymetry near Glaciar Perito Moreno, Upsala, and Viedma, large calving glaciers of the Southern Patagonia Icefield. The thermal structures of these lakes were significantly different from those reported in glacial fjords. There was no indication of upwelling subglacial meltwater; instead, turbid and cold glacial water discharge filled the region near the lake bottom. This was because water density was controlled by suspended sediment concentrations rather than by water temperature. Near-surface wind-driven circulation reaches a depth of similar to 180 m, forming a relatively warm isothermal layer (mean temperature of similar to 5-6 degrees C at Perito Moreno, similar to 3-4 degrees C at Upsala, and similar to 6-7 degrees C at Viedma), which should convey heat energy to the ice-water interface. However, the deeper part of the glacier front is in contact with stratified cold water, implying a limited amount of melting there. In the lake in front of Glaciar Viedma, the region deeper than 120 m was filled entirely with turbid and very cold water at pressure melting temperature. Our results revealed a previously unexplored thermal structure of proglacial lakes in Patagonia, suggesting its importance in the subaqueous melting of freshwater calving glaciers.

Tide-modulated ice flow variations drive seismicity near the calving front of Bowdoin Glacier, Greenland
Evgeny A. Podolskiy, Shin Sugiyama, Martin Funk, Fabian Walter, Riccardo Genco, Shun Tsutaki, Masahiro Minowa, Maurizio Ripepe
GEOPHYSICAL RESEARCH LETTERS, 43, 5, 2036, 2044, AMER GEOPHYSICAL UNION, Mar. 2016, [Peer-reviewed]
English, Scientific journal, Glacier microseismicity is a promising tool to study glacier dynamics. However, physical processes connecting seismic signals and ice dynamics are not clearly understood at present. Particularly, the relationship between tide-modulated seismicity and dynamics of calving glaciers remains elusive. Here we analyze records from an on-ice seismometer placed 250m from the calving front of Bowdoin Glacier, Greenland. Using high-frequency glacier flow speed measurements, we show that the microseismic activity is related to strain rate variations. The seismic activity correlates with longitudinal stretching measured at the glacier surface. Both higher melt rates and falling tides accelerate glacier motion and increase longitudinal stretching. Long-term microseismic monitoring could therefore provide insights on how a calving glacier's force balance and flow regime react to changes at the ice-ocean interface.

Reconstruction of climate during the past 157years by analyzing an ice core obtained from Northwestern Greenland Ice Sheet (SIGMA-D)
Kadota Moe, Matoba Sumito, Motoyama Hideaki, Fujita Koji, Yamasaki Tetsuhide, Onuma Yukihiko, Minowa Masahiro, Komuro Yuki, Aoki Teruo
Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2015, 191, 191, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2015
Japanese

Analysis of the total concentration of metals in the Greenland, SIGMA-D shallow ice core
Komuro Yuki, Suzuki Toshitaka, Onuma Yukihiko, Minowa Masahiro, Yamasaki Tetsuhide, Matoba Sumito, Fujita Koji, Hirabayashi Motohiro, Motoyama Hideaki, Aoki Teruo
Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2015, 166, 166, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2015
Japanese

Glaciological and meteorological observations at the SIGMA-D site, northwestern Greenland Ice Sheet
Sumito Matoba, Hideaki Motoyama, Koji Fujita, Tetsuhide Yamasaki, Masahiro Minowa, Yukihiko Onuma, Yuki Komuro, Teruo Aoki, Satoru Yamaguchi, Shin Sugiyama, Hiroyuki Enomoto
BULLETIN OF GLACIOLOGICAL RESEARCH, 33, 7, 14, NIHON SEPPYO GAKKAI-JAPANESE SOC SNOW & ICE, 2015, [Peer-reviewed]
English, Scientific journal, During spring 2014, we drilled an ice core on the northwestern Greenland Ice Sheet, recovering a core of total length 225 m. We also conducted stratigraphic observations, measurements of the density of the ice core, near-infrared photography of the ice core, preparation of liquid samples for chemical analysis, and measurements of borehole temperature. The pore close-off depth was 60 m, and the temperature in the borehole was -25.6 degrees C. at a depth of 10 m. In addition, we conducted snow-pit observations, ice-velocity and surface-elevation measurements using the global positioning system (GPS), meteorological observations, and installation of an automated weather station (AWS).

Contrasting glacier variations of Glaciar Perito Moreno and Glaciar Ameghino, Southern Patagonia Icefield
Masahiro Minowa, Shin Sugiyama, Daiki Sakakibara, Takanobu Sawagaki
ANNALS OF GLACIOLOGY, 56, 70, 26, 32, CAMBRIDGE UNIV PRESS, 2015, [Peer-reviewed], [Lead author]
English, Scientific journal, Glaciar Perito Moreno (GPM) and Glaciar Ameghino (GA), Southern Patagonia Icefield, are in contact in the accumulation area, but have shown contrasting frontal variations in the past few decades. To investigate recent changes of the two glaciers and processes controlling the different responses to similar climate conditions, we measured surface elevation change from 2000 to 2008 and terminus positions from 1999 to 2012 using several types of satellite data. GPM shows no significant changes in terminus position and 0.4 +/- 0.3 m a(-1) thickening over the period, whereas GA retreated 55 +/- 2 m a(-1) and thinned 2.6 +/- 0.3 m a(-1). Mass-balance measurements over the period 1999/2000 show that accumulation at GPM was ten times greater than that at GA, but ablation was only three times greater. The mass-balance-altitude profile is similar for the two glaciers; differences in the mass-balance distribution are caused by differences in the accumulation-area ratio (AAR). Our results suggest that the AAR and the calving flux exert strong control on the evolution of glaciers in the region.

Changes in frontal position and surface elevation of Glacier Perito Moreno and Glacier Ameghino, Patagonia
Minowa, M., Sakakibara, D., Sugiyama, S., Sawagaki, T.
Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2012, 1, 2012
Scientific journal

Spatiotemporal reconstruction of accumulation rate on the South East Dome in the Greenland Ice Sheet using ground-penetrating radar
坂田 宙斗, 箕輪 昌紘, 藤田 耕史, 的場 澄人, 川上 薫, 松本 真依, 飯塚 芳徳, 北海道の雪氷, 43, Sep. 2024
Summary national conference, 42667905

Long-term monitoring of icequakes in the grounding zone of Langhovde Glacier, East Antarctica
箕輪 昌紘, 近藤 研, Evgeny Podolskiy, 藤田 耕史, 杉山 慎, 43, Sep. 2024, [Lead author]
Summary national conference, 36786495

多視点インターバルカメラ撮影によるカービング現象の観測　　　　　　　　　　　　　　　
箕輪昌紘, 雪氷研究大会講演要旨集, Oct. 2023, [Lead author, Corresponding author]
Summary national conference

Long-term monitoring of icequakes at the grounding zone of Langhovde Glacier, East Antarctica　　　　　　　　　　　　　　　
Masahiro Minowa, Ken Kondo, Evgeny Podolskiy, Shin Sugiyama, 雪氷研究大会講演要旨集, Oct. 2023, [Lead author, Corresponding author]
English, Summary national conference

Rapid mass loss at ungrounded terminus of lake-terminating glaciers, southern Patagonia
箕輪昌紘, マリウス シェーファー, ペドロ スクヴァルカ, 雪氷研究大会講演要旨集, Oct. 2022, [Lead author, Corresponding author]
Japanese, Summary national conference, 36786495

Surface mass balance and climate observed at Glaciar Perito Moreno in Patagonia　　　　　　　　　　　　　　　
箕輪昌紘, 藤田耕史, ペドロスクバルカ, 雪氷研究大会講演要旨集, Sep. 2021, [Lead author]
Summary national conference

Hot-water drilling for exploration of the Antarctic subglacial environments
杉山慎, 箕輪昌紘, 伊藤優人, 山根志織, 雪氷, 83, 1, 2021, [Peer-reviewed]

Subglacial bedforms and carbonate deposits at Glaciar Viedma, Patagonia.
澤柿教伸, 箕輪昌紘, 日本地理学会発表要旨集, 97, 2020

Subglacial bedforms and carbonate deposits at Glaciar Viedma, Patagonia.
澤柿教伸, 箕輪昌紘, 日本地理学会発表要旨集, 98, 2020

Numerical modeling of glacier frontal ablation based by observational dataset
箕輪昌紘, 杉山慎, Truffer Martin, Skvarca Pedro, 雪氷研究大会講演要旨集(Web), 2020, 2020
Report research institution

Year-round oceanic measurements under the ice shelf of Langhove Glacier in Antarctica
杉山慎, 箕輪昌紘, 雪氷研究大会講演要旨集(Web), 2019, 2019

Short-term ice speed variation at Glaciar Tempano, Patagonia
箕輪昌紘, Schaefer Marius, 波多俊太郎, 雪氷研究大会講演要旨集(Web), 2019, 2019

Streamline bedrock erosion and till observed at Glaciar Viedma, Patagonia
澤柿教伸, 箕輪昌紘, 箕輪昌紘, 安藤卓人, Skvarca Pedro, 雪氷研究大会講演要旨集(Web), 2018, 2018

Hot-water drilling at Langhove Glacier in Antarctica
杉山慎, 箕輪昌紘, 箕輪昌紘, 伊藤優人, 山根志織, 山根志織, 雪氷研究大会講演要旨集(Web), 2018, 2018

Subshelf environment of Langhovde Glacier, Antarctica
山根志織, 山根志織, 杉山慎, 箕輪昌紘, 伊藤優人, 雪氷研究大会講演要旨集(Web), 2018, 2018

南極ラングホブデ氷河における氷河下の海洋環境
山根志織, 山根志織, 杉山慎, 箕輪昌紘, 伊藤優人, 日本海洋学会大会講演要旨集, 2018, 2018

Changes of ice-front position in Langhovde Glacier, Antarctica
山根志織, 山根志織, 箕輪昌紘, 杉山慎, 雪氷研究大会講演要旨集(Web), 2017, 2017

Influence of bed geometry on the retreat of Glaciar Grey in the Southern Patagonia Icefield
山本淳博, 山本淳博, 杉山慎, 箕輪昌紘, 雪氷研究大会講演要旨集(Web), 2017, 2017

Underwater ice front structure plays a role in calving at Grey Glacier in Patagonia
杉山慎, 箕輪昌紘, 山本淳博, 山本淳博, Schaefer Marius, 雪氷研究大会講演要旨集(Web), 2017, 2017

Study on frontal ablation of a freshwater calving glacier in the Southern Patagonia Icefield
Minowa Masahiro, Sugyama Shin, Sakakibara Daiki, Skvarca Pedro, Ohashi Yoshihiko, Sawagaki Takanobu, Naito Nozomu, Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2016, 0, 184, 184, 2016
The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, Japanese

Effects from ocean and atmosphere on ice-front position of tidewater glaciers, northwest Greenland
Minowa Masahiro, Sugiyama Shin, Sawagaki Takanobu, Tsutaki Shun, Sakakibara Daiki, Ohashi Yoshihiko, Aoki Shigeru, Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2016, 0, 29, 29, 2016
The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, Japanese

Recent ice mass loss in northwestern Greenland — Results of the GRENE Greenland project and overview of the ArCS —
Sugiyama Shin, Matsuno Satoshi, Sawagaki Takanobu, Matoba Sumito, Greve Ralf, Seddik Hakime, Funk Martin, Genco Riccardo, Enomoto Hiroyuki, Tsutaki Shun, Sakakibara Daiki, Saito Jun, Ohashi Yoshihiko, Maruyama Mihiro, Katayama Naoki, Podolskiy Evgeny, Minowa Masahiro, Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2016, 0, 224, 224, 2016
The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, Japanese

Recent ice mass loss in northwestern Greenland - Results of the GRENE Greenland project and overview of the ArCS -
杉山慎, 津滝俊, 津滝俊, 榊原大貴, 榊原大貴, 斉藤潤, 斉藤潤, 大橋良彦, 大橋良彦, 丸山未妃呂, 丸山未妃呂, 片山直紀, 片山直紀, Podolskiy Evgeny, 箕輪昌紘, 箕輪昌紘, 松野智, 松野智, 澤柿教伸, 的場澄人, Greve Ralf, Seddik Hakime, Funk Martin, Genco Riccardo, 榎本浩之, 雪氷研究大会講演要旨集(Web), 2016, 2016

Recent retreat of Glaciar Grey in the Southern Patagonia Icefield
山本淳博, 山本淳博, 箕輪昌紘, 箕輪昌紘, 杉山慎, 雪氷研究大会講演要旨集(Web), 2016, 2016

Calving front of Grey Glacier in Patagonia is sticking out to the lake under the water surface
杉山慎, 箕輪昌紘, 箕輪昌紘, Schaefer Marius, 雪氷研究大会講演要旨集(Web), 2016, 2016

Mechanisms for rapid reterat and speedup of Glanciar Upsala, Southern Patagonia Icefield
榊原大貴, 榊原大貴, 杉山慎, 箕輪昌紘, 箕輪昌紘, Skvarca Pedro, 雪氷研究大会講演要旨集(Web), 2015, 2015

Mechanisms of frontal ablation change, Glaciar Perito Moreno Patagonia
箕輪昌紘, 箕輪昌紘, 杉山慎, 榊原大貴, 榊原大貴, Pedro Skvarca, 大橋良彦, 大橋良彦, 澤柿教伸, 内藤望, 雪氷研究大会講演要旨集(Web), 2015, 2015

Seasonal variation in ice-front position of Bowdoin Glacier, northwest Greenland
箕輪昌紘, 箕輪昌紘, 杉山慎, 雪氷研究大会講演要旨集(Web), 2015, 2015

グリーンランド北西氷床のアイスコア掘削について―SIGMA‐D経過報告―
本山秀明, 的場澄人, 藤田耕史, 山崎哲秀, 大沼友貴彦, 箕輪昌紘, 小室悠紀, 山口悟, 青木輝夫, 雪氷研究大会講演要旨集, 2014, 62, 2014
The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, Japanese

南パタゴニア氷原ウプサラ氷河の後退および流動加速に底面地形が与える影響
榊原大貴, 榊原大貴, 箕輪昌紘, 箕輪昌紘, 杉山慎, 澤柿教伸, 内藤望, SKVARCA Pedro, 雪氷研究大会講演要旨集, 2014, 2014

南パタゴニア氷原におけるカービング氷河前縁湖の水温構造
杉山慎, 箕輪昌紘, 箕輪昌紘, 榊原大貴, 榊原大貴, 大橋良彦, 大橋良彦, SKVARCA Pedro, 澤柿教伸, 内藤望, 知北和久, 雪氷研究大会講演要旨集, 2014, 2014

南パタゴニア氷原ペリート・モレノ氷河における末端変動メカニズムの解明
箕輪昌紘, 箕輪昌紘, 杉山慎, SKVARCA Pedro, 榊原大貴, 榊原大貴, 大橋良彦, 大橋良彦, 澤柿教伸, 内藤望, 雪氷研究大会講演要旨集, 2014, 2014

2013年12月南パタゴニア氷原ペリート・モレノ氷河における表面測量
内藤望, 箕輪昌紘, 箕輪昌紘, 榊原大貴, 榊原大貴, 大橋良彦, 大橋良彦, 澤柿教伸, 杉山慎, SKVARCA Pedro, 雪氷研究大会講演要旨集, 2014, 2014

Glaciers in the Southern Patagonia Icefield
SUGIYAMA Shin, SAWAGAKI Takanobu, SAKAKIBARA Daiki, MINOWA Masahiro, MUTO Minami, NAITO Nozomu, SKVARCA Pedro, 雪氷 : 日本雪氷協會雜誌, 75, 5, i, ii, 15 Sep. 2013
Japanese

南パタゴニア氷原ビエドマ氷河前縁湖における観測
箕輪昌紘, 箕輪昌紘, 杉山慎, 澤柿教伸, 内藤望, 榊原大貴, 榊原大貴, 武藤みなみ, SKVARCA Pedro, 雪氷研究大会講演要旨集, 2013, 2013

グリーンランド北西部における氷河・氷帽の表面高度変化
斉藤潤, 斉藤潤, 榊原大貴, 榊原大貴, 箕輪昌紘, 箕輪昌紘, 津滝俊, 津滝俊, 澤柿教伸, 杉山慎, 雪氷研究大会講演要旨集, 2013, 2013

南パタゴニア氷原ペリートモレノ氷河における氷河末端位置の季節変動
箕輪昌紘, 箕輪昌紘, 杉山慎, SKVARCA Pedro, 雪氷研究大会講演要旨集, 2013, 2013

南パタゴニア氷原の3つのカービング氷河における短期流動変化の同時測定
杉山慎, 澤柿教伸, 内藤望, 榊原大貴, 榊原大貴, 箕輪昌紘, 箕輪昌紘, 武藤みなみ, 雪氷研究大会講演要旨集, 2013, 2013

南パタゴニア氷原ペリート・モレノ氷河における氷厚変動観測
内藤望, 箕輪昌紘, 箕輪昌紘, 榊原大貴, 榊原大貴, 澤柿教伸, 武藤みなみ, 杉山慎, SKVARCA Pedro, 雪氷研究大会講演要旨集, 2013, 2013

パタゴニア・ペリートモレノ氷河,アメギノ氷河における末端変動と氷厚変化
箕輪昌紘, 箕輪昌紘, 榊原大貴, 榊原大貴, 杉山慎, 澤柿教伸, 雪氷研究大会講演要旨集, 2012, 2012

北極域の研究 : その現状と将来構想
北極環境研究コンソーシアム長期構想編集委員会, 北極環境研究コンソーシアム, 氷床の氷流出（流動・末端消耗）
海文堂出版, Mar. 2024, 9784303562304, x, 468p, Japanese, [Contributor]

氷河氷床特論　　　　　　　　　　　　　　　
Apr. 2023 - Present

地球雪氷学実習　　　　　　　　　　　　　　　
Apr. 2022 - Present

地球雪氷学基礎論　　　　　　　　　　　　　　　
Apr. 2022 - Present

Jun. 2012 - Present
International Glaciological Society　　　　　　　　　　　　　　　

Unraveling spatio-temporal variations of the Antarctic ice sheet mass balance and its governing mechanisms
Grants-in-Aid for Scientific Research
01 Apr. 2024 - 31 Mar. 2029
庭野 匡思, 杉山 慎, 箕輪 昌紘, 津滝 俊
Japan Society for the Promotion of Science, Grant-in-Aid for Transformative Research Areas (A), Japan, Meteorological Research Institute, 24H02342

Mechanism of glacier calving and its influence on the glacier fluctuation
Grants-in-Aid for Scientific Research
01 Apr. 2022 - 31 Mar. 2025
箕輪 昌紘
Japan Society for the Promotion of Science, Grant-in-Aid for Early-Career Scientists, Hokkaido University, 22K14093

汎用型氷レーダーによるデータ取得, 解析, 可視化手法の確立
ROIS-DS-JOINT
Jun. 2023 - Mar. 2024
大学共同利用機関情報・システム研究機構, 低温科学研究所, Principal investigator, 036RP2023

Investigation of firn structure and its impacts on glacier runoff in the Greenland Ice Sheet　　　　　　　　　　　　　　　
Apr. 2022 - Mar. 2024
箕輪昌紘
ArCSⅡ, Principal investigator

カービング氷河の急速な質量損失メカニズム：現地データに基づいた数値モデリング
科学研究費助成事業 特別研究員奨励費
24 Apr. 2020 - 31 Mar. 2023
箕輪 昌紘
南米パタゴニアのペリートモレノ氷河、ウプサラ氷河においてアラスカ大学と共同で運用していたインターバルカメラをそれぞれ回収した。2018年の設置以来、2年間の氷河変動を記録することに成功している。その後合計4台のカメラを、近年急速に後退しているヴィエドマ氷河周辺の基盤上に設置しデータ取得を開始した。ペリートモレノ氷河において長期間連続で精密な氷河流動を測定する為に、二周波受信GPSを氷河上に設置し、毎秒の氷河流動を測定し始めた。これらのデータは現地協力者によって随時保守点検やデータ回収が行われている。
ペリートモレノ氷河で実施している気象観測や氷河表面質量収支の観測データについてデータ解析を推進した。気象の経年変動や表面質量収支モデルによる表面質量収支の計算を実施した。近年にかけて表面融解量が増加する様子が明らかとなった。また、この氷河で計算された質量収支は、南半球の気候を主に制御するエルニーニョ・南方振動や南半球環状モードといった地球規模の気象現象との関係が示唆される結果が得られつつある。
氷河の末端消耗プロセスを理解するために、氷河流動モデルの構築を行なった。当初はアラスカ大学を訪れ数値モデルの習得を目指していたが、疫病蔓延のため申請者自身で構築を進めた。有限要素法を用いて氷河流線に沿った二次元の力平行方程式を解き、氷河流動と圧力を計算した。計算される氷の歪みより、末端消耗プロセスに関連する主応力やせん断応力が計算できるようになった。
日本学術振興会, 特別研究員奨励費, 名古屋大学, 20J00526

淡水性カービング氷河の後退に末端消耗が果たす役割の解明
科学研究費助成事業 特別研究員奨励費
25 Apr. 2018 - 31 Mar. 2021
箕輪 昌紘
日本学術振興会, 特別研究員奨励費, 名古屋大学, 18J00188

急速に後退する氷河・氷床の変動に海・湖が果たす役割の解明
科学研究費助成事業 特別研究員奨励費
22 Apr. 2016 - 31 Mar. 2018
箕輪 昌紘
パタゴニアのペリート・モレノ氷河においてカービングの測定手法の提案とカービング発生メカニズムについて解析を行った．これまでほとんど用いられていなかった水面波を使うことでカービングの頻度や氷山の体積を定量的に推定できることが提案した．またカービングの発生メカニズムについてはデータの測定期間が短期であったことから十分に考察できなかったが，平均気温と平均カービング発生回数はよく一致しており，今後長期の観測をすることが発生メカニズムを明らかにする上で重要であることが示唆された．これらの研究成果は，Journal of Glaciology誌に投稿し受理された．同様の解析はグリーンランドのボードイン氷河やアラスカのルコンテ氷河でも実施しており，現在研究成果の発表に向け準備中である．
氷河末端の水中融解の重要性についてパタゴニアの氷河湖で他時期に測定をした水温や濁度を解析することで考察を行った．解析・考察の結果，同じ気候条件であるにも関わらず氷河湖によって水温構造は大きく異なることが明らかとなった．またこの違いには，氷河融解水流出量と湖の深度が重要な影響を持つことが明らかになった．これらの結果は同地域に存在する氷河でも水中融解の重要性は大きく異なる可能性を示唆している．現在研究成果を国際誌への出版に向け準備中である．
パタゴニアの氷河での一連の研究成果については2017年7月にベルリンで開催された国際シンポジウムで発表を行った．
日本学術振興会, 特別研究員奨励費, 北海道大学, 16J01860

Direct measurement of subaqueous melting at the front of calving glaciers
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
01 Apr. 2014 - 31 Mar. 2017
Sugiyama Shin, SAWAGAKI TAKANOBU, YAMAZAKI SHINTARO, MINOWA MASAHIRO, SAKAKIBARA DAIKI, SCHAEFER MARIUS, SKVARCA PEDRO
This project aimed to quantify subaqueous melting at the front of calving glaciers by mapping under-water ice geometry using a side-scanning sonar. We operated a sonar (Imagenex Model 872) in proglacial lakes and fjords in Patagonia, Greenland and Antarctica. At the front of Grey Glacier, a freshwater calving glacier in Patagonia, we found the ice front was extending into the lake by 50-100 m under the water surface. Together with water temperature distributions in the lake, our observation implies that ice melting is enhanced near the water surface. Melt rate was not quantified only from the sonar data, but water temperature, turbidity and isotope measurements enabled us to estimate the subaqueous melting rate at the front of Grey Glacier. The results provided new insights into the frontal ablation and evolution of freshwater calving glaciers.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 26550001

Oct. 2024 - Nov. 2024
Rolwaling, Nepal, glaciological observations

Sep. 2024 - Sep. 2024
南パタゴニア氷原

Nov. 2023 - Mar. 2024
第65次南極観測隊 夏隊

Apr. 2023 - Apr. 2023
南パタゴニア氷原 氷河調査

Mar. 2023 - Mar. 2023
グリーンランド北西部カナック氷帽&トレーシー氷河

Oct. 2022 - Oct. 2022
Trambau Glacier, Nepal

Jun. 2022 - Jul. 2022
Qaanaaq Ice Cap, Northwest Greenland

Oct. 2021 - Apr. 2022
The 63rd Japanese Antarctic Research Expedition

Apr. 2021 - Jun. 2021
SE-Dome, South Eest Greenland

Oct. 2018 - Oct. 2020
パタゴニア氷原の複数の氷河での水深測量

Oct. 2018 - Oct. 2018
南パタゴニア氷原涵養域での観測

Nov. 2017 - Mar. 2018
The 59th Japanese Antarctic Research Expedition

Jan. 2017 - Feb. 2017
グレイ氷河前縁の氷河湖観測

Mar. 2016 - Mar. 2016
ペリートモレノ氷河でのカービング津波観測

Jan. 2016 - Feb. 2016
南極半島リビングストン島での氷河観測

Jul. 2015 - Aug. 2015
グリーンランド北西部ボードイン氷河での氷河観測

Oct. 2014 - Oct. 2014
南パタゴニア氷原での氷河・氷河湖観測

Apr. 2014 - Jun. 2014
グリーンランド北西部SIGMA-Dでのアイスコア掘削

Dec. 2013 - Jan. 2014
南パタゴニア氷原での氷河・氷河湖観測

Dec. 2012 - Jan. 2013
南パタゴニア氷原での氷河観測