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Iizuka Yoshinori

Institute of Low Temperature Science　Frontier Ice and Snow ScienceProfessor
Arctic Research CenterProfessor

Researcher basic information

■ Degree
  • 博士（理学）, 総合研究大学院大学
■ URL
researchmap URLホームページURL■ Various IDs
J-Global ID■ Research Keywords and Fields
Research Keyword
  • 氷床コア
  • 南極
  • 第四紀
  • 季節変動
  • エアロゾル
  • 古環境復元
  • アイスコア
  • 極地
  • 環境変動
  • 地球化学
  • 古環境変動
  • イオン濃度
  • 無機イオン濃度
  • 塩微粒子
  • 地球環境変動
  • 氷床
  • 時間スケール
  • 陸域水循環・物質循環
  • フィルン
  • AIMイベント
  • D-0イベント
  • ドームふじ
  • 高時間分解能解析
  • 気候変動
  • ミランコビッチ理論
  • ダストフラックス
  • 雪
  • 結晶組織
  • 地球規模環境変動
  • 地球規模気候変動
Research Field
  • Environmental Science/Agriculture Science, Environmental dynamic analysis
  • Natural Science, Atmospheric and hydrospheric sciences
■ Educational Organization

Career

■ Career
Career
  • 2007 - 2012
    Hokkaido University, Institute of Low Temperature Science, 助教

Research activity information

■ Awards
  • Sep. 2011, 日本雪氷学会, 平田賞
    飯塚芳徳
■ Papers
  • Variations in aerosol composition inferred from metal concentrations in the SE-Dome ice core, southeastern Greenland
    Nao Esashi; Chiaki Sasaki; Toshitaka Suzuki; Motohiro Hirabayashi; Yoshinori Iizuka; Sumito Matoba; Koji Fujita
    Polar Science, 101303, 101303, Elsevier BV, Oct. 2025
    Scientific journal
  • Evaluation of sample storage methods for single particle analyses of black carbon in snow and ice: Merits and risks of glass and plastic vials for melted sample storage
    Sayako Ueda; Sho Ohata; Yoshinori Iizuka; Osamu Seki; Sumito Matoba; Hitoshi Matsui; Makoto Koike; Yutaka Kondo
    Aerosol Science and Technology, 1, 16, Informa UK Limited, 14 Aug. 2025
    Scientific journal
  • Development and fluctuation of crystal orientation fabric in the deep sections of the Dome Fuji ice core, Antarctica: impacts of dust particles and migration recrystallization
    Tomotaka Saruya; Atsushi Miyamoto; Shuji Fujita; Kumiko Goto-Azuma; Motohiro Hirabayashi; Akira Hori; Makoto Igarashi; Yoshinori Iizuka; Takao Kameda; Hiroshi Ohno; Wataru Shigeyama; Shun Tsutaki
    The Cryosphere, 19, 7, 2365, 2385, Copernicus GmbH, 03 Jul. 2025
    Scientific journal, Abstract. This study investigated the crystalline textural properties of an Antarctic deep ice core with a length of 3035 m acquired from an inland plateau dome, with a focus on depths below 2400 m. The cluster strength of the c axes was ascertained using the dielectric tensor method to assess the bulk properties of thick sections, and detailed orientation distributions of the c and a axes were determined using the Laue X-ray diffraction technique. The c- and a-axis fabric data were compared with various other characteristics of the same ice core. Microstructural observations were made using optical microscopy. The clustering strength of the single-pole c-axis fabric was at a maximum at depths between 2400 and 2640 m. The relationship between the cluster strength and the concentration of dusty impurities was found to change at approximately 2640 m, and fluctuations in strength increased significantly below this depth. Impurity-rich layers maintained a high degree of clustering, whereas layers with fewer impurities showed relaxation. The latter layers also exhibited evidence of nucleation and grain boundary migration. In ice such as this, the degree of a-axis organization was increased with one or two sets of three preferred orientations. Dynamic recrystallization evidently played a critical role, with more pronounced effects in impurity-poor layers than in impurity-rich layers. This phenomenon promoted the relaxation of the c-axis clustering, deformation based on dislocation creep and organization of the a axis. Below 2580 m, the angles of inclination of the c-axis cluster and layers deviated significantly from the vertical, suggesting that the system rotated as a rigid body as a result of simple shear.
  • Multidecadal Variability in Atmospheric Dust Preserved in an Ice Core From the Southern Slopes of the Himalayas
    Nao Esashi; Akane Tsushima; Sumito Matoba; Yoshinori Iizuka; Ryu Uemura; Rijan B. Kayastha; Koji Fujita
    Journal of Geophysical Research: Atmospheres, 130, 12, American Geophysical Union (AGU), 12 Jun. 2025
    Scientific journal, Abstract

    Ice cores from the Himalayan region, downwind from vast arid and densely populated areas, are important in revealing long‐term dust variability and the driving factors behind such variability. However, logistical challenges in reaching the region have hindered the retrieval of long‐term dust records from the southern side of the Himalayas. This study presents a 145‐year record of atmospheric dust from an 81.2‐m ice core drilled in the Trambau (TB) glacier, a south‐facing glacier in the Nepal Himalaya, covering 1875–2019 CE. Comparison of dust records from the northern and southern slopes of the Himalayas indicates that the ice core from the southern slopes has preserved higher dust concentrations and larger particle sizes than records from the northern slopes. Furthermore, the TB core record shows 50‐ to 70‐year multidecadal variability, positively correlated with the Atlantic Multidecadal Oscillation (AMO). Based on correlation and composite analyses using ERA5 reanalysis data, AMO phases have been linked with surface wetness/dryness in dust source regions in the Middle East and Southwest Asia, likely contributing to variations in dust loading at the TB core site.
  • A 60-year atmospheric nitrate isotope record from a southeastern Greenland ice core with minimal postdepositional alteration
    Zhao Wei; Shohei Hattori; Asuka Tsuruta; Zhuang Jiang; Sakiko Ishino; Koji Fujita; Sumito Matoba; Lei Geng; Alexis Lamothe; Ryu Uemura; Naohiro Yoshida; Joel Savarino; Yoshinori Iizuka
    Atmospheric Chemistry and Physics, 25, 11, 5727, 5742, Copernicus GmbH, 11 Jun. 2025
    Scientific journal, Abstract. Stable isotopes of atmospheric nitrate (NO3-) are valuable tools for tracing nitrogen sources and processes; however, their signals in ice core records are often disrupted by postdepositional processes. The ice core from the southeastern Dome (SE-Dome) in Greenland is a potential record of variations in atmospheric chemistry that has experienced a lower postdepositional effect owing to a high accumulation rate (∼1 m water equivalent per year). Herein, we report 60-year (1959–2014) δ15N(NO3-) and Δ17O(NO3-) records from the SE-Dome ice core. The δ15N(NO3-) decreased from 1960 to 1974 and exhibited clear seasonal changes (high in summer and low in winter). The Δ17O(NO3-) did not exhibit any significant long-term trends, but it did contain seasonal patterns. The mass-weighted annual average of δ15N(NO3-) values in the SE-Dome core were 4.2±2.8 ‰ lower than those in the Greenland Summit ice core between 1959 and 2006. The TRansfer of Atmospheric Nitrate Stable Isotopes To the Snow (TRANSITS) model under the SE-Dome condition estimated changes of only 0.9 ‰ for δ15N(NO3-) and −0.2 ‰ for Δ17O(NO3-) from the initial deposition. Although differences in the source of NO3- cannot be discounted, the lower δ15N(NO3-) values observed at SE-Dome compared to Summit were likely due to reduced postdepositional alteration. Therefore, the SE-Dome ice core NO3- record offers a precise reconstruction of nitrogen oxides (NOx) emissions from both North America and western Europe, as well as atmospheric oxidation chemistry and transport, thereby providing reliable insight into atmospheric nitrogen cycling.
  • Acidity-driven gas-particle partitioning of nitrate regulates its transport to Arctic through the industrial era
    Yoshinori Iizuka; Mai Matsumoto; Kaoru Kawakami; Mahiro Sasage; Sakiko Ishino; Shohei Hattori; Ryu Uemura; Hitoshi Matsui; Koji Fujita; Naga Oshima; Andrea Spolaor; Anders Svensson; Bo Møllesøe Vinther; Hiroshi Ohno; Osamu Seki; Sumito Matoba
    Nature Communications, 16, 1, Springer Science and Business Media LLC, 19 May 2025
    Scientific journal
  • Contrasting Responses of Ion Concentration Variations to Atmospheric Patterns in Central Himalayan Ice Cores
    Akane Tsushima; Nao Esashi; Sumito Matoba; Yoshinori Iizuka; Ryu Uemura; Kouji Adachi; Takeshi Kinase; Motohiro Hirabayashi; Kaoru Kawakami; Rijan B. Kayastha; Koji Fujita
    Journal of Geophysical Research: Atmospheres, 130, 2, American Geophysical Union (AGU), 23 Jan. 2025
    Scientific journal, Abstract

    We analyzed the water‐soluble chemical composition of an 81.2‐m‐long ice core collected in 2019 from 6,000 m elevation on a south‐facing glacier in the Nepal Himalaya. The ice core chronology is based on variability in nitrate and calcium ions, which reveal an apparently seasonal periodicity (with winter maxima) throughout the core's length. Two annual boundaries are consistent with the tritium peak representing nuclear tests conducted in 1963 CE and with the spike in sulfate ions due to the eruption of Krakatau in 1883 CE. The ice core spans 145 years from 1875 to 2019 CE. Dating uncertainties due to the layer counting methodology were estimated as year for 1963–2019 CE and years for 1875–1963 CE. Comparison with earlier ice cores drilled on the northern side of the Himalayas revealed that the ion components exhibit inverse correlations with two key climatic indices: the North Atlantic Oscillation and Southern Oscillation Index. Composite analysis of reanalysis climate data suggests that these inverse relationships reflect springtime pressure patterns, which show regional differences between the northern and southern sides of the Himalayan range.
  • Atmospheric dust record preserved in an ice core from Trambau Glacier, Nepal Himalaya
    Nao Esashi; Akane Tsushima; Ryu Uemura; Sumito Matoba; Yoshinori Iizuka; Kouji Adachi; Takeshi Kinase; Rijan B. Kayastha; Koji Fujita
    09 Mar. 2024
  • Development of deformational regimes and microstructures in the deep sections and overall layered structures of the Dome Fuji ice core, Antarctica
    Tomotaka Saruya; Atsushi Miyamoto; Shuji Fujita; Kumiko Goto-Azuma; Motohiro Hirabayashi; Akira Hori; Makoto Igarashi; Yoshinori Iizuka; Takao Kameda; Hiroshi Ohno; Wataru Shigeyama; Shun Tsutaki
    05 Jan. 2024
  • 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
    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.
  • Increased oceanic dimethyl sulfide emissions in areas of sea ice retreat inferred from a Greenland ice core
    Yutaka Kurosaki; Sumito Matoba; Yoshinori Iizuka; Koji Fujita; Rigen Shimada
    Communications Earth & Environment, 3, 1, Springer Science and Business Media LLC, 26 Dec. 2022
    Scientific journal, Abstract

    Ocean phytoplankton are an important source of dimethyl sulfide, which influences marine cloud formation. Model studies suggest that declines in Arctic sea ice may lead to increased dimethyl sulfide emissions, however observational support is lacking. Here, we present a 55-year high-resolution ice core record of methane sulfonic acid flux, an oxidation product of dimethyl sulfide, from the southeast Greenland Ice Sheet. We infer temporal variations in ocean dimethyl sulfide emissions and find that springtime (April–June) fluxes of methane sulfonic acid correlate well with satellite-derived chlorophyll-a concentration in the Irminger Sea. Summertime (July–September) methane sulfonic acid fluxes were 3 to 6 times higher between 2002–2014 than 1972–2001. We attribute this to sea ice retreat day becoming earlier and a coincident increase in chlorophyll-a concentration in the adjacent open coastal waters.
  • Inclusions in ice layers formed by melting and refreezing processes in a Greenland ice core
    Kaoru Kawakami; Yoshinori Iizuka; Sumito Matoba; Teruo Aoki; Takuto Ando
    Journal of Glaciology, 1, 13, Cambridge University Press (CUP), 21 Nov. 2022
    Scientific journal, Abstract

    In recent decades, surface melting on the inland Greenland ice sheet has increased, leading to significant meltwater-refreezing in the snow and firn. Increased knowledge of the physical and chemical characteristics of these melt features (i.e., ice layers) is needed to help estimate future global sea-level rise. Here, using a combination of microscopy and spectroscopy, we investigate the size, shape, location, and chemical compositions of inclusions in 12 ice layers of the SIGMA-A ice core in the northwestern Greenland ice sheet (78°03′06″N, 67°37′42″W, 1490 m a.s.l.). In the ice layers, we found inclusions exceeding 30 μm diameter that could only be formed by melting–refreezing, which we classify into columnar-, particle-, and rod-like inclusions. We propose that the smaller columnar- and particle-like inclusions of solid Na2SO4⋅10H2O and CaSO4⋅2H2O form first, within the ice grains, followed by the larger rod-like inclusions of brines with mainly Na+ and Cl− in grain boundaries. Our results suggest a new proxy that may help identify past warm climates in deeper ice cores in Greenland and for studying future ice sheet melting behavior.
  • High Flux of Small Sulfate Aerosols During the 1970s Reconstructed From the SE‐Dome Ice Core in Greenland
    Y. Iizuka; R. Uemura; H. Matsui; N. Oshima; K. Kawakami; S. Hattori; H. Ohno; S. Matoba
    Journal of Geophysical Research: Atmospheres, 16 Sep. 2022, [Peer-reviewed]
    English, Scientific journal
  • Development of crystal orientation fabric in the Dome Fuji ice core in East Antarctica: implications for the deformation regime in ice sheets
    Tomotaka Saruya; Shuji Fujita; Yoshinori Iizuka; Atsushi Miyamoto; Hiroshi Ohno; Akira Hori; Wataru Shigeyama; Motohiro Hirabayashi; Kumiko Goto-Azuma
    The Cryosphere, 16, 7, 2985, 3003, Copernicus GmbH, 27 Jul. 2022
    Scientific journal, Abstract. The crystal orientation fabric (COF) of a polar ice sheethas a significant effect on the rheology of the ice sheet. With the aim ofbetter understanding the deformation regime of ice sheets, the workpresented here investigates the COF in the upper 80 % of the Dome FujiStation ice core in East Antarctica. Dielectric anisotropy (Δε) data were acquired as a novel indicator of the verticalclustering of COF resulting from vertical compressional strain within thedome. The Δε values were found to exhibit a generalincrease with depth, but with fluctuations over distances in the order of10–102 m. In addition, significant decreases in Δεwere found to be associated with depths corresponding to three major glacialto interglacial transitions. These changes in Δε areascribed to variations in the deformational history caused by dislocationmotion occurring from near-surface depths to deeper layers. Fluctuations inΔε over distances of less than 0.5 m exhibited a stronginverse correlation with Δε at depths greater thanapproximately 1200 m, indicating that they were enhanced during theglacial-interglacial transitions. The Δε data alsoexhibited a positive correlation with the concentration of chloride ions andan inverse correlation with the amount of dust particles in the ice core atgreater depths corresponding to decreases in the degree of c axis clustering.Finally, we found that fluctuations in Δε persisted toapproximately 80 % of the total depth of the ice sheet. These data suggestthat the factors determining the deformation of ice include theconcentration of chloride ions and the amount of dust particles, and thatthe layered contrast associated with the COF is preserved all the way fromthe near-surface to a depth corresponding to approximately 80 % of thethickness of the ice sheet. These findings provide important implicationsregarding further development of the COF under the various stress-strainconfigurations that the ice will experience in the deepest region,approximately 20 % of the total depth from the ice/bed interface.
  • Gypsum formation from calcite in the atmosphere recorded in aerosol particles transported and trapped in Greenland ice core sample is a signature of secular change of SO2 emission in East Asia
    Chihiro Miyamoto; Yoshinori Iizuka; Sumito Matoba; Shohei Hattori; Yoshio Takahashi
    Atmospheric Environment, 278, 119061, 119061, Elsevier BV, Jun. 2022
    Scientific journal
  • Soluble salts in deserts as a source of sulfate aerosols in an Antarctic ice core during the last glacial period
    Ryu Uemura; Kosuke Masaka; Yoshinori Iizuka; Motohiro Hirabayashi; Hitoshi Matsui; Risei Matsumoto; Miki Uemura; Koji Fujita; Hideaki Motoyama
    Earth and Planetary Science Letters, 578, 117299, 117299, Elsevier BV, Jan. 2022
    Scientific journal
  • Pure rotational Raman spectroscopy applied to N2/O2 analysis of air bubbles in polar firn
    Hiroshi Ohno; Yoshinori Iizuka; Shuji Fujita
    Journal of Glaciology, 67, 265, 903, 908, Cambridge University Press (CUP), Oct. 2021
    Scientific journal, AbstractEarlier gas measurements of firn air (atmosphere in open pore channels) at polar sites have revealed the occurrence of gas fractionation phenomena during bubble close-off, in addition to well-known thermal and gravitational gas separation. Nevertheless, because of difficulties posed by measurement, little is known about the distribution of air constituents in already closed pores (bubbles) in firn. Herein, we describe the application of high-sensitivity pure rotational Raman spectroscopy, combined with sample immersion in the fluorocarbon-based inert fluid for removing the optical disturbance by diffused reflection. That application efficiently elicits information about nitrogen and oxygen composition ratios (N2/O2 or O2/N2) for each air bubble in firn. The developed methodology presents important implications for elucidating how gas records are formed and modified in the course of pore close-off in polar firn.
  • Physically Based Summer Temperature Reconstruction From Melt Layers in Ice Cores
    Koji Fujita; Sumito Matoba; Yoshinori Iizuka; Nozomu Takeuchi; Akane Tsushima; Yutaka Kurosaki; Teruo Aoki
    Earth and Space Science, 8, 7, American Geophysical Union ({AGU}), 17 Jul. 2021
    Scientific journal
  • Isotopic evidence for acidity-driven enhancement of sulfate formation after SO2 emission control
    Shohei Hattori; Yoshinori Iizuka; Becky Alexander; Sakiko Ishino; Koji Fujita; Shuting Zhai; Tomás Sherwen; Naga Oshima; Ryu Uemura; Akinori Yamada; Nozomi Suzuki; Sumito Matoba; Asuka Tsuruta; Joel Savarino; Naohiro Yoshida
    Science Advances, 7, 19, eabd4610, eabd4610, American Association for the Advancement of Science (AAAS), May 2021
    Scientific journal, After the 1980s, atmospheric sulfate reduction is slower than the dramatic reductions in sulfur dioxide (SO2) emissions. However, a lack of observational evidence has hindered the identification of causal feedback mechanisms. Here, we report an increase in the oxygen isotopic composition of sulfate (Δ17OSO42−) in a Greenland ice core, implying an enhanced role of acidity-dependent in-cloud oxidation by ozone (up to 17 to 27%) in sulfate production since the 1960s. A global chemical transport model reproduces the magnitude of the increase in observed Δ17OSO42− with a 10 to 15% enhancement in the conversion efficiency from SO2 to sulfate in Eastern North America and Western Europe. With an expected continued decrease in atmospheric acidity, this feedback will continue in the future and partially hinder air quality improvements.
  • Increasing dust emission from ice free terrain in southeastern Greenland since 2000
    Tomomi Amino; Yoshinori Iizuka; Sumito Matoba; Rigen Shimada; Naga Oshima; Toshitaka Suzuki; Takuto Ando; Teruo Aoki; Koji Fujita
    Polar Science, 27, 100599, 100599, Elsevier {BV}, Mar. 2021
    Scientific journal
  • Inclusions in ice layers of an ice core, Greenland
    Kawakami Kaoru; Iizuka Yoshinori; Matoba Sumito; Aoki Teruo; Sugiyama Shin; Ando Takuto
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2021, 34, 34, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2021
    Japanese
  • The analysis of water stable isotopes of the ice core from Trambau glacier, Nepal Himalaya
    Esashi Nao; Tsushima Akane; Uemura Ryu; Iizuka Yoshinori; Matoba Sumito; Fujita Koji
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2021, 21, 21, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2021
    Japanese
  • Isotopic evidence for changes in sulfate formation after SO2 emission control
    Hattori Shohei; Iizuka Yoshinori; Alexander Becky; Ishino Sakiko; Fujita Koji; Zhai Shuting; Sherwen Tomas; Oshima Naga; Uemura Ryu; Yamada Akinori; Suzuki Nozomi; Matoba Sumito; Tsuruta Asuka; Savarino Joel; Yoshida Naohiro
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 68, 158, GEOCHEMICAL SOCIETY OF JAPAN, 2021
    Japanese, 大気中の硫酸の三酸素同位体組成は、大気中におけるSO2から硫酸への酸化過程における酸化剤の寄与率を反映して変動する。本研究では、グリーンランド南東ドームで採取された過去60年分のアイスコアを用い、その硫酸の三酸素同位体組成を分析することで、過去の大気化学反応の変化を復元した。硫酸の三酸素同位体組成は過去60年間で上昇し、SO2の液相O3酸化の寄与率が高くなっていたことを示した。硫酸の三酸素同位体組成の中和率やH+フラックスの変化とよく相関していた。SO2の液相O3酸化は酸性度が低いほど促進されることから、1980年代以降のSO2排出量の削減とアンモニア排出の増加による大気中酸性度の低下が促進の要因であると考えられる。このように、硫酸の三酸素同位体組成の分析によって、SO2排出規制にも関わらず硫酸エアロゾルの減少が鈍化するケミカルフィードバック機構の要因が、大気酸性度の低下によるSO2の液相O3酸化の促進であることが特定された。
  • Ice Core Drilling and the Related Observations at SE-Dome site, southeastern Greenland Ice Sheet
    Yoshinori IIZUKA; Sumito MATOBA; Masahiro MINOWA; Tetsuhide YAMASAKI; Kaoru KAWAKAMI; Ayako KAKUGO; Morihiro MIYAHARA; Akihiro HASHIMOTO; Masashi NIWANO; Tomonori TANIKAWA; Koji FUJITA; Teruo AOKI
    Bulletin of Glaciological Research, 39, 1, 12, Japanese Society of Snow and Ice, 2021
    Scientific journal
  • 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 Bjørk; Toku Oshima
    Polar Science, 27, 2021
    Scientific journal
  • Reconstruction of sea ice concentration in northern Baffin Bay using deuterium excess in a coastal ice core from the northwestern Greenland Ice Sheet
    Yutaka Kurosaki; Sumito Matoba; Yoshinori Iizuka; Masashi Niwano; Tomonori Tanikawa; Takuto Ando; Akira Hori; Atsushi Miyamoto; Shuji Fujita; Teruo Aoki
    Journal of Geophysical Research: Atmospheres, 125, 16, American Geophysical Union (AGU), Aug. 2020, [Peer-reviewed]
    Scientific journal
  • Compositions of Dust and Sea Salts in the Dome C and Dome Fuji Ice Cores From Last Glacial Maximum to Early Holocene Based on Ice‐Sublimation and Single‐Particle Measurements
    I. Oyabu; Y. Iizuka; K. Kawamura; E. Wolff; M. Severi; R. Ohgaito; A. Abe‐Ouchi; M. Hansson
    Journal of Geophysical Research: Atmospheres, 125, 4, American Geophysical Union ({AGU}), 27 Feb. 2020
    Scientific journal
  • Inclusions in ice layers of SIGMA-A ice core, northwestern Greenland
    Kawakami Kaoru; Iizuka Yoshinori; Matoba Sumito; Aoki Teruo; Sugiyama Shin; Ando Takuto
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2020, 66, 66, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2020
    Japanese
  • ArCS II Cryosphere Research 3 “Water and material circulations in seasonal sea ice regions and their impacts on environment in the Arctic”
    Matoba Sumito; Iizuka Yoshinori; Miyazaki Yuzo; Suzuki Toshitaka; Hattori Shohei; Uemura Ryu; Hara Keiichiro; Oshima Naga; Yamasaki Tetsuhide; Aoki Teruo
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2020, 111, 111, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2020
    Japanese
  • Sulfate aerosol composition and flux during 1970’s derived from the SE-Dome ice core, Greenland
    Iizuka Yoshinori; Uemura Ryu; Matsui Hitoshi; Oshima Naga; Matoba Sumito
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2020, 67, 67, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2020
    Japanese
  • Measurements of beryllium isotopes in ice wedges in Alaska
    Kazuho Horiuchi; Hiroshi Ohno; Go Iwahana; Yoshinori Iizuka; Hiroyuki Matsuzaki
    Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 459, 64, Elsevier {BV}, Nov. 2019, [Peer-reviewed]
  • Reduced marine phytoplankton sulphur emissions in the Southern Ocean during the past seven glacials
    Goto-Azuma K; Hirabayashi M; Motoyama H; Miyake T; Kuramoto T; Uemura R; Igarashi M; Iizuka Y; Sakurai T; Horikawa S; Suzuki K; Suzuki T; Fujita K; Kondo Y; Hattori S; Fujii Y
    Nature Communications, 10, 1, 324, Jul. 2019, [Peer-reviewed]
    English, Scientific journal
  • Metal elements in snow and ice core from H128, Antarctica
    Nishino Saori; Suzuki Toshitaka; Iizuka Yoshinori; Hirabayashi Motohiro; Kawamura Kenji; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2019, 83, 83, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2019
    Japanese
  • The analysis of metal elements in the Dome Fuji deep ice core, Antarctica - Reconstruction of sea ice extent fluctuations from the concentration of sea salt sodium
    Esashi Nao; Suzuki Toshitaka; Iizuka Yoshinori; Hirabayashi Motohiro; Kawamura Kenji; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2019, 84, 84, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2019
    Japanese
  • Open-sea and sea-ice fluctuations in nearshore Beaufort Sea during the last deglaciation derived from ion concentrations in ice wedge
    Iizuka, Y; C. Miyamoto; S. Matoba; G. Iwahana; K. Horiuchi; Y. Takahashi; N. Kanna; K. Suzuki; H. Ohno
    Earth and Planetary Science Letter, 515, 58, 66, 2019, [Peer-reviewed]
    English, Scientific journal
  • Ion concentrations in ice wedges: An innovative approach to reconstruct past climate variability
    Iizuka Yoshinori; Miyamoto Chihiro; Matoba Sumito; Iwahana Go; Horiuchi Kazuho; Takahashi Yoshio; Kanna Naoya; Suzuki Koji; Ohno Hiroshi
    Earth and Planetary Science Letters, 515, 58, 66, Elsevier {BV}, 2019, [Peer-reviewed]
    Scientific journal
  • Assessment for paleoclimatic utility of biomass burning tracers in SE-Dome ice core, Greenland
    Parvin F; Seki O; Fujita K; Iizuka Y; Matoba S; Ando T; Sawada K
    Atmospheric Environment, 196, 86, 94, Jan. 2019, [Peer-reviewed]
    English, Scientific journal
  • Asynchrony between Antarctic temperature and CO2 associated with obliquity over the past 720,000 years
    Ryu Uemura; Hideaki Motoyama; Valérie Masson-Delmotte; Jean Jouzel; Kenji Kawamura; Kumiko Goto-Azuma; Shuji Fujita; Takayuki Kuramoto; Motohiro Hirabayashi; Takayuki Miyake; Hiroshi Ohno; Koji Fujita; Ayako Abe-Ouchi; Yoshinori Iizuka; Shinichiro Horikawa; Makoto Igarashi; Keisuke Suzuki; Toshitaka Suzuki; Yoshiyuki Fujii
    Nature Communications, 9, 1, 01 Dec. 2018, [Peer-reviewed]
    English, Scientific journal
  • High-resolution 129I bomb peak profile in an ice core from SE-Dome site, Greenland
    Angel T. Bautista; Yasuto Miyake; Hiroyuki Matsuzaki; Yoshinori Iizuka; Kazuho Horiuchi
    Journal of Environmental Radioactivity, 184-185, 14, 21, 01 Apr. 2018, [Peer-reviewed]
    English, Scientific journal
  • NHM-SMAP: Spatially and temporally high-resolution nonhydrostatic atmospheric model coupled with detailed snow process model for Greenland Ice Sheet
    Masashi Niwano; Teruo Aoki; Akihiro Hashimoto; Sumito Matoba; Satoru Yamaguchi; Tomonori Tanikawa; Koji Fujita; Akane Tsushima; Yoshinori Iizuka; Rigen Shimada; Masahiro Hori
    Cryosphere, 12, 2, 635, 655, 23 Feb. 2018, [Peer-reviewed]
    English, Scientific journal
  • A 60 Year Record of Atmospheric Aerosol Depositions Preserved in a High-Accumulation Dome Ice Core, Southeast Greenland
    Yoshinori Iizuka; Ryu Uemura; Koji Fujita; Shohei Hattori; Osamu Seki; Chihiro Miyamoto; Toshitaka Suzuki; Naohiro Yoshida; Hideaki Motoyama; Sumito Matoba
    Journal of Geophysical Research: Atmospheres, 123, 1, 574, 589, Wiley-Blackwell, 16 Jan. 2018, [Peer-reviewed]
    Scientific journal
  • Field activities at the SIGMA-A site, northwestern Greenland Ice Sheet, 2017
    Matoba Sumito; Niwano Masashi; Tanikawa Tomonori; Iizuka Yoshinori; Yamasaki Tetsuhide; Kurosaki Yutaka; Aoki Teruo; Hashimoto Akihiro; Hosaka Masahiro; Sugiyama Shin
    Bulletin of Glaciological Research, 36, 0, 15, 22, 2018, [Peer-reviewed]
    Scientific journal
  • Past 60 years changes in oxidation pathways of tropospheric sulfur from triple oxygen isotopic composition of sulfate preserved in SE-Dome ice core
    Hattori Shohei; Iizuka Yoshinori; Uemura Ryu; Suzuki Nozomi; Tsuruta Asuka; Ishino Sakiko; Fujita Koji; Matoba Sumito; Yoshida Naohiro
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 65, 12, GEOCHEMICAL SOCIETY OF JAPAN, 2018
    Japanese, グリーンランドの氷床コアは北アメリカやヨーロッパ由来の大気が由来し、過去のエアロゾル動態を復元する貴重な環境媒体である。産業革命以降の人間活動の増大に伴い、大気中に放出される硫黄及び窒素酸化物の濃度が上昇し、1970年以降に北アメリカ、ヨーロッパで排出が抑制された。事実、氷床コア中の硫酸濃度の減少がSO2排出量の減少と対応していることが知られている。本研究では、グリーンランド南東ドーム(SE-Dome)で採取された約90 m、60年分のアイスコアを用い、時間解像度3~6年で硫酸の三酸素同位体組成を分析した。
  • Transportation of aerosol studied from metal elements in snow from H128, Antarctica
    Nishino Saori; Arai Miho; Suzuki Toshitaka; Iizuka Yoshinori; Hirabayashi Motohiro; Kawamura Kenji; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2018, 23, 23, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2018
    Japanese
  • Variation of Al/Dust ratio in the Dome Fuji deep ice core, Antarctica
    Yonekura Ayaka; Suzuki Toshitaka; Iizuka Yoshinori; Hirabayashi Motohiro; Motoyama Hideaki; Kawamura Kenji
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2018, 22, 22, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2018
    Japanese
  • バフィン湾周辺の環境がグリーンランド北西部の降雪中のd-excessと化学成分に与える影響
    黒﨑豊; 的場澄人; 飯塚芳徳; 庭野匡思; 谷川朋範; 青木輝夫
    雪氷, 80, 6, 515, 529, 2018, [Peer-reviewed]
  • Seasonal-Scale Dating of a Shallow Ice Core From Greenland Using Oxygen Isotope Matching Between Data and Simulation
    Ryoto Furukawa; Ryu Uemura; Koji Fujita; Jesper Sjolte; Kei Yoshimura; Sumito Matoba; Yoshinori Iizuka
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 122, 20, 10873, 10887, Oct. 2017, [Peer-reviewed]
    English, Scientific journal
  • Overview of the chemical composition and characteristics of Na+ and Cl– distributions in samples from Antarctic ice core DF01 (Dome Fuji) drilled in 2001
    Yuko Motizuki; K. Takahashi; Y. Nakai; Y. Iizuka; K. Suzuki; H. Motoyama
    RIKEN Accel. Prog. Rep., 49, 133, Mar. 2017, [Peer-reviewed]
  • State dependence of climatic instability over the past 720,000 years from Antarctic ice cores and climate modeling
    Kenji Kawamura; Ayako Abe-Ouchi; Hideaki Motoyama; Yutaka Ageta; Shuji Aoki; Nobuhiko Azuma; Yoshiyuki Fujii; Koji Fujita; Shuji Fujita; Kotaro Fukui; Teruo Furukawa; Atsushi Furusaki; Kumiko Goto-Azuma; Ralf Greve; Motohiro Hirabayashi; Takeo Hondoh; Akira Hori; Shinichiro Horikawa; Kazuho Horiuchi; Makoto Igarashi; Yoshinori Iizuka; Takao Kameda; Hiroshi Kanda; Mika Kohno; Takayuki Kuramoto; Yuki Matsushi; Morihiro Miyahara; Takayuki Miyake; Atsushi Miyamoto; Yasuo Nagashima; Yoshiki Nakayama; Takakiyo Nakazawa; Fumio Nakazawa; Fumihiko Nishio; Ichio Obinata; Rumi Ohgaito; Akira Oka; Jun'ichi Okuno; Junichi Okuyama; Ikumi Oyabu; Frederic Parrenin; Frank Pattyn; Fuyuki Saito; Takashi Saito; Takeshi Saito; Toshimitsu Sakurai; Kimikazu Sasa; Hakime Seddik; Yasuyuki Shibata; Kunio Shinbori; Keisuke Suzuki; Toshitaka Suzuki; Akiyoshi Takahashi; Kunio Takahashi; Shuhei Takahashi; Morimasa Takata; Yoichi Tanaka; Ryu Uemura; Genta Watanabe; Okitsugu Watanabe; Tetsuhide Yamasaki; Kotaro Yokoyama; Masakazu Yoshimori; Takayasu Yoshimoto
    SCIENCE ADVANCES, 3, 2, Feb. 2017, [Peer-reviewed]
    English, Scientific journal
  • A firn densification process in the high accumulation dome of southeastern Greenland
    Yoshinori Iizuka; Atsushi Miyamoto; Akira Hori; Sumito Matoba; Ryoto Furukawa; Takeshi Saito; Shuji Fujita; Motohiro Hirabayashi; Satoru Yamaguchi; Koji Fujita; Nozomu Takeuchi
    ARCTIC ANTARCTIC AND ALPINE RESEARCH, 49, 1, 13, 27, Feb. 2017, [Peer-reviewed]
    English, Scientific journal
  • Seasonal scale dating of a shallow ice core from Greenland using oxygen isotope matching between data and simulation
    Furukawa Ryoto; Uemura Ryu; Fujita Koji; Sjolte Jesper; Yoshimura Kei; Matoba Sumito; Iizuka Yoshinori
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 64, 18, 18, GEOCHEMICAL SOCIETY OF JAPAN, 2017
    Japanese,

  • The past 60 years variation of nitrogen isotopic composition of nitrate preserved in SE-Dome site, southeastern Greenland Ice Sheet
    Tsuruta Asuka; Hattori Shohei; Iizuka Yoshinori; Fujita Koji; Uemura Ryu; Matoba Sumito; Yoshida Naohiro
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 64, 19, 19, GEOCHEMICAL SOCIETY OF JAPAN, 2017
    Japanese,

  • Analysis of insoluble particles in the ice core from south-east dome, Greenland
    Amino Tomomi; Iizuka Yoshinori; Matoba Sumito
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 154, 154, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
    Japanese
  • The past 60 years variations of sources and formation pathways of nitrate preserved in SE-Dome site, southeastern Greenland Ice Sheet
    Tsuruta Asuka; Hattori Shohei; Iizuka Yoshinori; Fujita Koji; Uemura Ryu; Matoba Sumito; Yoshida Naohiro
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 120, 120, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
    Japanese
  • Field activities at the northwestern Greenland Ice Sheet (SIGMA-A site) in 2017
    Matoba Sumito; Niwano Masashi; Tanikawa Tomonori; Iizuka Yoshinori; Yamasaki Tetsuhide; Kurosaki Yutaka; Aoki Teruo; Hashimoto Akihiro; Hosaka Masahiro; Sugiyama Shin
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 288, 288, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
    Japanese
  • Relationship between metal elements and microparticles in the Dome Fuji deep ice core, Antarctica
    Yonekura Ayaka; Suzuki Toshitaka; Iizuka Yoshinori; Hirabayashi Motohiroi; Kawamura Kenji; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 30, 30, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
    Japanese
  • Metal elements in the ice sheet surface in the south of Dome Fuji, Antarctica
    Suzuki Toshitaka; Shoji Airi; Shibata Mai; Iizuka Yoshinori; Hirabayashi Motohitro; Kawamura Kenji; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 29, 29, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
    Japanese
  • Fluctuations of total concentration of metals recorded in the ice core from southeast dome, Greenland
    Sasaki Chiaki; Suzuki Toshitaka; Hirabayashi Motohiro; Iizuka Yoshinori
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 28, 28, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
    Japanese
  • Reconstruction of paleoclimate past 100 years from ice core at northwestern Greenland Ice Sheet
    Kurosaki Yutaka; Matoba Sumito; Iizuka Yoshinori; Aoki Teruo; Sugiyama Shin
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2017, 191, 191, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2017
    Japanese
  • Characteristics of Na+ and Cl– distributions in shallow samples from an Antarctic ice core DF01 (Dome Fuji) drilled in 2001: Result of strong atmospheric high-pressure blocking events?
    Y. Motizuki; H. Motoyama; Y. Nakai; K. Suzuki; Y. Iizuka; K. Takahashi
    RIKEN Accel. Prog. Rep., 50, 144, 2017, [Peer-reviewed]
    English
  • Seasonal variations in the major chemical species of snow at the South East Dome in Greenland
    Ikumi Oyabu; Sumito Matoba; Tetsuhide Yamasaki; Moe Kadota; Yoshinori Iizuka
    POLAR SCIENCE, 10, 1, 36, 42, Mar. 2016, [Peer-reviewed]
    English, Scientific journal
  • Sulfur isotope measurement of sulfate aerosols in an Antarctic ice core
    Uemura Ryu; Masaka Kosuke; Matsumoto Risei; Uemura Miki; Iizuka Yoshinori; Hirabayashi Motohiro; Motoyama Hideaki
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 63, 23, GEOCHEMICAL SOCIETY OF JAPAN, 2016
    Japanese, 硫酸エアロゾルは、直接・間接効果によって気候変動に影響を与える物質である。その硫黄安定同位体比(δ34S)は、起源ごとに特有の値を持つとともに、酸化過程による分別によって変動することも知られている。したがって、アイスコアのδ34S値から、過去数万年スケールの硫酸エアロゾルの変動メカニズムや起源推定が行える可能性がある。本研究では、最終氷期から完新世にかけてのドームふじアイスコアのδ34Sを測定し、変動メカニズムの解析を行った。DF1コアの完新世のδ34S値は、現在の東南極表面積雪の値と誤差範囲で一致していた。また、DF1コアのδ34Sは、最終氷期から完新世にかけての温暖化に対応して、高くなる傾向を示した。
  • Temperature and accumulation rate reconstructions from the ice core in south-east dome, Greenland
    Furukawa Ryoto; Iizuka Yoshinori; Matoba Sumito; Uemura Ryu
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2016, 31, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2016
    Japanese
  • The next deep ice coring in the Dome Fuji region, East Antarctica
    Kawamura Kenji; Iizuka Y.; Uemura R.; Uchida T.; Oono H.; Kameda T.; Suzuki T.; Takata M.; Hirabayashi M.; Fujita K.; Fukui K.; Motoyama H.; Hori A.; Horiuchi K.; Matoba S.; Miyamoto A.; Goto-Azuma K.; Fujita S.; Furukawa T.; Nakazawa F.; Aoki S.; Azuma N.; Abe-Ouchi A.
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2016, 194, 194, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2016
    Japanese
  • Spatial distributions of soluble salts in surface snow of East Antarctica
    Yoshinori Iizuka; Hiroshi Ohno; Ryu Uemura; Toshitaka Suzuki; Ikumi Oyabu; Yu Hoshina; Kotaro Fukui; Motohiro Hirabayashi; Hideaki Motoyama
    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY, 68, 2016, [Peer-reviewed]
    English, Scientific journal
  • Observation of the snow pit and atmospheric aerosols at the South-East Dome in Greenland
    Oyabu Ikumi; Iizuka Yoshinori; Matoba Sumito; Yamasaki Tetsuhide; Kadota Moe
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2015, 73, 73, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2015
    Japanese
  • Metal components in the Dome Fuji deep ice core, Antarctica
    Arai Miho; Suzuki Toshitaka; Iizuka Yoshinori; Hirabayashi Motohiro; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2015, 208, 208, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2015
    Japanese
  • Metal composition of basal ice at Dome Fuji, Antarctica
    Kumagai Kohei; Suzuki Toshitaka; Iizuka Yoshinori; Hirabayashi Motohiro; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2015, 209, 209, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2015
    Japanese
  • Chemical compositions of solid particles present in the Greenland NEEM ice core over the last 110,000 years
    Ikumi Oyabu; Yoshinori Iizuka; Hubertus Fischer; Simon Schüpbach; Gideon Gfeller; Anders Svensson; Manabu Fukui; Jørgen Peder Steffensen; Margareta Hansson
    Journal of Geophysical Research, 120, 18, 9789, 9813, Wiley-Blackwell, 2015, [Peer-reviewed]
    English, Scientific journal
  • Chemical compositions of sulfate and chloride salts over the last termination reconstructed from the dome fuji ice core, inland antarctica
    Ikumi Oyabu; Yoshinori Iizuka; Ryu Uemura; Takayuki Miyake; Motohiro Hirabayashi; Hideaki Motoyama; Toshimitsu Sakurai; Toshitaka Suzuki; Takeo Hondoh
    Journal of Geophysical Research, 119, 24, 14, 058, Wiley-Blackwell, 27 Dec. 2014, [Peer-reviewed]
    English, Scientific journal
  • Chemical compositions of sulfate and chloride salts over the last termination reconstructed from the Dome Fuji ice core, inland Antarctica
    Ikumi Oyabu; Yoshinori Iizuka; Ryu Uemura; Takayuki Miyake; Motohiro Hirabayashi; Hideaki Motoyama; Toshimitsu Sakurai; Toshitaka Suzuki; Takeo Hondoh
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 119, 24, 14045, 14058, Dec. 2014, [Peer-reviewed]
    English, Scientific journal
  • Effect of accumulation rate on water stable isotopes of near-surface snow in inland Antarctica
    Yu Hoshina; Koji Fujita; Fumio Nakazawa; Yoshinori Iizuka; Takayuki Miyake; Motohiro Hirabayashi; Takayuki Kuramoto; Shuji Fujita; Hideaki Motoyama
    Journal of Geophysical Research, 119, 1, 274, 283, Wiley-Blackwell, 16 Jan. 2014, [Peer-reviewed]
    English, Scientific journal
  • 日本-スウェーデン共同南極トラバース2007/2008実施報告(1)企画立案・事前準備と科学研究成果の概要
    藤田 秀二; 福井 幸太郎; 中澤 文男; 榎本 浩之; 杉山 慎; 藤井 理行; 藤田 耕史; 古川 晶雄; 原 圭一郎; 保科 優; 五十嵐 誠; 飯塚 芳徳; 伊村 智; 本山 秀明; Surdyk Sylviane; 植村 立; Shuji Fujita; Kotaro Fukui; Fumio Nakazawa; Hiroyuki Enomoto; Shin Sugiyama; Yoshiyuki Fujii; Koji Fujita; Teruo Furukawa; Keiichiro Hara; Yu Hoshina; Makoto Igarashi; Yoshinori Iizuka; Satoshi Imura; Hideaki Motoyama; Sylviane Surdyk; Ryu Uemura
    南極資料, 58, 3, 352, 392, 国立極地研究所, 2014, [Peer-reviewed]
    Japanese, Scientific journal, 南極地域観測第Ⅶ期5か年計画に基づき，2007/2008 年の南極の夏期シーズンに，国立極地研究所を中心とした研究グループは，スウェーデンの研究者グループと共同で，東南極内陸域のドロンイングモードランド地域の内陸部の氷床環境調査を実施した．本報告は，現地調査前に5年間を費やした研究計画の企画検討の経過や行った事前準備と，現地野外観測を終了した後の6年間に得られた研究成果の概要をまとめるものである．本プロジェクトの調査により，南極内陸高原部の氷床環境の時空間分布について，多くの科学的知見が明らかになった．本報告はその概要を報告する．現地調査の実行の経過は別途の報告に記述する．In the seventh five-year plan of the Japanese Antarctic Research Expedition, a group of Japanese scientists (led by the National Institute of Polar Research) together with a group of Swedish scientists, conducted field surveys to better understand the glaciology of the ice sheet in Dronning Maud Land, East Antarctica, during the 2007/2008 austral summer season. This paper reports on the planning and field preparations, and outlines the scientific achievements of the field expedition. We have gained numerous new scientific insights on the spatio-temporal distribution of the ice sheet environment in the inland plateau. Here, we provide an overview of the new knowledge gained.
  • Effect of accumulation rate on water stable isotopes of near-surface snow in inland Antarctica
    Yu Hoshina; Koji Fujita; Fumio Nakazawa; Yoshinori Iizuka; Takayuki Miyake; Motohiro Hirabayashi; Takayuki Kuramoto; Shuji Fujita; Hideaki Motoyama
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 119, 1, 274, 283, Jan. 2014, [Peer-reviewed]
    English, Scientific journal
  • Mineral and Sea-Salt Aerosol Fluxes over the Last 340 kyr Reconstructed from the Total Concentration of Al and Na in the Dome Fuji Ice Core
    SatoH, SuzukiT; HirabayashiM; MotoyamaH; IizukaY; FujiiY
    Atmospheric and Climate Sciences, 3, 186, 192, 2013, [Peer-reviewed]
    Scientific journal
  • The rates of sea salt sulfatization in the atmosphere and surface snow of inland Antarctica
    Yoshinori Iizuka; Akira Tsuchimoto; Yu Hoshina; Toshimitsu Sakurai; Margareta Hansson; Torbjorn Karlin; Koji Fujita; Fumio Nakazawa; Hideaki Motoyama; Shuji Fujita
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 117, Feb. 2012, [Peer-reviewed]
    English, Scientific journal
  • Study of precise measurement for borehole temperature in glacier and ice sheet
    Motoyama Hideaki; Furusaki Atsushi; Takahashi Hiromu; Takata Morimasa; Takahashi Akiyoshi; Miyahara Morihiro; Motoba Sumito; Sugiyama Shin; Iizuka Yoshinori; Shinbori Kunio
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2012, 161, 161, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2012
    Japanese
  • Potassium alum and aluminum sulfate micro-inclusions found in Antarctic ice from Dome Fuji
    Ohno Hiroshi; Iizuka Yoshinori; Hondoh Takeo; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2012, 159, 159, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2012
    Japanese
  • Post-depositional change of water stable isotope and major ion concentration by snow accumulation environment in inland Antarctica
    Hoshina Yu; Fujita Koji; Nakazawa Fumio; Iizuka Yoshinori; Miyake Takayuki; Hirabayashi Motohiro; Kuramoto Takayuki; Motoyama Hideaki; Fujita Shuji
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2012, 121, 121, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2012
    Japanese
  • Formation and metamorphism of stratified firn at sites located under spatial variations of accumulation rate and wind speed on the East Antarctic ice divide near Dome Fuji
    Fujita, S; Enomoto, H; Fukui, K; Iizuka, Y; Motoyama, H; Nakazawa, F; Sugiyama, S; Surdyk, S
    The Cryosphere Discussions, 6, 2, 1205-1267, 3, 2012
    English, Abstract. The initial stage of postdepositional metamorphism in polar firn was investigated at sites located under spatial variations of accumulation rate and wind speed along the East Antarctic ice divide near Dome Fuji. A better understanding of this process is important for interpreting local insolation proxies used for astronomical dating of deep ice cores. Three 2–4 m deep pits were excavated and physical properties, including density ρ, grain size D, reflectance R of near infrared light and microwave dielectric anisotropy Δε, were investigated at high spatial resolution. We found that Δε ranges between 0.028 and 0.067 and that such high values occur in the surface ~0.1 m. In addition, short scale variations of ρ are correlated with those of Δε, and inversely correlated with those of D, confirming contrasting development of initially higher density layers and initially lower density layers. Moreover, postdepositional metamorphism makes these contrasts more distinct with increasing depths. Both the contrasts and Δε for given values of ρ are higher under lower accumulation rate conditions and under less windy conditions. Insolation efficiently causes evolution of strata of firn at the ice sheet surface under such conditions. Under more windy conditions, the strata contain more wind-driven hard layers with higher ρ and Δε and thus have larger fluctuations of ρ and Δε. We suggest that the initial variability of ρ at the surface and the duration of exposure to diurnal and seasonal temperature gradients play sequential roles in determining the physical/mechanical properties of firn, which is retained throughout the densification process.
  • Spatial and temporal variability of snow accumulation rate on the East Antarctic ice divide between Dome Fuji and EPICA DML
    S. Fujita; P. Holmlund; I. Andersson; I. Brown; H. Enomoto; Y. Fujii; K. Fujita; K. Fukui; T. Furukawa; M. Hansson; K. Hara; Y. Hoshina; M. Igarashi; Y. Iizuka; S. Imura; S. Ingvander; T. Karlin; H. Motoyama; F. Nakazawa; H. Oerter; L. E. Sjöberg; S. Sugiyama; S. Surdyk; J. Ström; R. Uemura; F. Wilhelms
    The Cryosphere, 5, 4, 1057, 1081, 28 Nov. 2011, [Peer-reviewed]
    Scientific journal
  • Dissociation Behavior of C2H6 Hydrate at Temperatures below the Ice Point: Melting to Liquid Water Followed by Ice Nucleation
    Hiroshi Ohno; Ikumi Oyabu; Yoshinori Iizuka; Takeo Hondoh; Hideo Narita; Jiro Nagao
    JOURNAL OF PHYSICAL CHEMISTRY A, 115, 32, 8889, 8894, Aug. 2011, [Peer-reviewed]
    English, Scientific journal
  • The chemical forms of water-soluble microparticles preserved in the Antarctic ice sheet during Termination I
    Toshimitsu Sakurai; Hiroshi Ohno; Shinichiro Horikawa; Yoshinori Iizuka; Tsutomu Uchida; Kazuomi Hirakawa; Takeo Hondoh
    JOURNAL OF GLACIOLOGY, 57, 206, 1027, 1032, 2011, [Peer-reviewed]
    English, Scientific journal
  • The behavior of sulfate and chloride ions in ice sheets as a function of increasing depth
    Toshimitsu Sakurai; Shinichiro Horikawa; Yoshinori Iizuka; Takayuki Miyake; Tsutomu Uchida; Takeo Hondoh
    Physics and Chemistry of Ice 2010 [Y. Furukawa, G. Sazaki, T. Uchida, N. Watanabe (Eds)], Institute of Low Temperature Science, Hokkaido University press, Hokkaido, Japan, 37, 44, 2011, [Peer-reviewed]
    English, Scientific journal
  • Symmetric Stretching Vibration of CH4 in Clathrate Hydrate Structures
    Hiroshi Ohno; Masato Kida; Toshimitsu Sakurai; Yoshinori Iizuka; Takeo Hondoh; Hideo Narita; Jiro Nagao
    CHEMPHYSCHEM, 11, 14, 3070, 3073, Oct. 2010, [Peer-reviewed]
    English, Scientific journal
  • Magnesium methanesulfonate salt found in the Dome Fuji (Antarctica) ice core
    Toshimitsu Sakurai; Hiroshi Ohno; F. Elif Genceli; Shinichirou Horikawa; Yoshinori Iizuka; Tsutomu Uchida; Takeo Hondoh
    JOURNAL OF GLACIOLOGY, 56, 199, 837, 842, 2010, [Peer-reviewed]
    English, Scientific journal
  • Evidence of past migration of the ice divide between the Shirase and Soya drainage basins derived from chemical characteristics of the marginal ice in the Soya drainage basin, East Antarctica
    Yoshinori Iizuka; Hideki Miura; Shogo Iwasaki; Hideaki Maemoku; Takanobu Sawagaki; Ralf Greve; Hiroshi Satake; Kimikazu Sasa; Yuki Matsushi
    JOURNAL OF GLACIOLOGY, 56, 197, 395, 404, 2010, [Peer-reviewed]
    English, Scientific journal
  • A Technique for Measuring Microparticles in Polar Ice Using Micro-Raman Spectroscopy
    T. Sakurai; H. Ohno; S. Horikawa; Y. Iizuka; T. Uchida; T. Hondoh
    International Journal of Spectroscopy, 2010, 384956-1, 384956-7, Hindawi Publishing Corporation, 2010, [Peer-reviewed]
    English, Scientific journal, We describe in detail our method of measuring the chemical forms of microparticles in polar ice samples through micro-Raman spectroscopy. The method is intended for solid ice samples, an important point because melting the ice can result in dissociation, contamination, and chemical reactions prior to or during a measurement. We demonstrate the technique of measuring the chemical forms of these microparticles and show that the reference spectra of those salts expected to be common in polar ice are unambiguously detected. From our measurements, Raman intensity of sulfate salts is relatively higher than insoluble dust due to the specific Raman scattering cross-section of chemical forms of microparticles in ice.
  • Meridianiite detected in ice
    F. Elif Genceli; Shinichirou Horikawa; Yoshinori Iizuka; Toshimitsu Sakurai; Takeo Hondoh; Toshiyuki Kawamura; Geert-Jan Witkamp
    JOURNAL OF GLACIOLOGY, 55, 189, 117, 122, 2009, [Peer-reviewed]
    English, Scientific journal
  • Direct observation of salts as micro-inclusions in the Greenland GRIP ice core
    Toshimitsu Sakurai; Yoshinori Iizuka; Shinichiro Horikawa; Sigfus Johnsen; Dorthe Dahl-Jensen; Jorgen Peder Steffensen; Takeo Hondoh
    JOURNAL OF GLACIOLOGY, 55, 193, 777, 783, 2009, [Peer-reviewed]
    English, Scientific journal
  • Constituent elements of insoluble and non-volatile particles during the Last Glacial Maximum exhibited in the Dome Fuji (Antarctica) ice core
    Yoshinori Iizuka; Takayuki Miyake; Motohiro Hirabayashi; Toshitaka Suzuki; Sumito Matoba; Hideaki Motoyama; Yoshiyuki Fujii; Takeo Hondoh
    JOURNAL OF GLACIOLOGY, 55, 191, 552, 562, 2009, [Peer-reviewed]
    English, Scientific journal
  • Chemical compounds of water-soluble impurities in Dome Fuji ice core (Physics of ice core records (2)) -- (Chemical properties and isotopes)
    Iizuka Yoshinori; Ohno Hiroshi; Sakurai Toshimitsu
    低温科学, 68, 273, 285, Institute of Low Temperature Science, Hokkaido University, 2009, [Peer-reviewed]
    English, Scientific journal, The amounts of water-soluble impurities in ice cores have been widely discussed in past research on prehistoric climates; in those studies, the analysis of the soluble-aerosol signals of several ion concentrations took place after the ice cores were melted. However, the chemical compounds of the impurities being studied were unclear, due to the ionization of the impurities being caused by the melting of the ice cores. In this paper, the chemical compounds of water-soluble impurities in Dome Fuji ice core are discussed and analyzed using micro-Raman spectroscopy and ion chromatography. Raman spectroscopy helped identify micro-inclusions within ice grains as water-soluble impurities made up primarily of sodium sulfate formed in warm periods and calcium sulfate in cold periods. The major chemical compounds of the water-soluble impurities (sodium sulfate and calcium sulfate) were deduced by examining ion concentrations and the stability of chemical compounds. The amounts of impurities reflect the differences in climatic time periods, as the environment was acidic during warm times and reductive during cold.Physics of Ice Core Records II : Papers collected after the 2nd International Workshop on Physics of Ice Core Records, held in Sapporo, Japan, 2-6 February 2007. Edited by Takeo Hondoh
  • 南極ドームふじ氷床コアによる過去72万年間の水溶性エアロゾルの主要組成変動
    飯塚 芳徳; 鈴木 利孝; 平林 幹啓; 三宅 隆之; 本山 秀明; 藤井 理行; 本堂 武夫
    日本地球化学会年会要旨集, 56, 39, 39, 日本地球化学会, 2009
    Japanese, 年平均気温が-50℃以下になる南極内陸地域はほぼすべての主要な水溶性エアロゾル塩が固体として存在するため、南極内陸の氷床コアは水溶性エアロゾルの良い保存媒体となる。発表者らは南極ドームふじで採取された氷コアを-50℃環境で昇華させ、残渣の不揮発性粒子の元素組成を分析した。その結果、不溶性粒子の99％にはSiが含まれ、主にシリカ鉱物であること、水溶性粒子のほとんどにはS、Clが含まれ、それぞれ硫酸塩や塩化物塩であることが示唆された。また、最近の氷期-間氷期サイクルにおける水溶性エアロゾルは、1)間氷期や氷期初期の硫酸ナトリウムが水溶性エアロゾルの主成分でエアロゾル濃度の低い時期、2)氷期中期の硫酸カルシウムが主成分で濃度の低い時期、3)氷期末期の硫酸カルシウムが主成分で濃度の高い時期という周期的な変遷をしていることが示唆された。
  • Postdepositional changes of chemical components in the snow at Dome Fuji, Antarctica
    Hoshina Yu; Fujita Koji; Nakazawa Fumio; Iizuka Yoshinori; Miyake Takayuki; Hirabayashi Motohiro; Kuramoto Takayuki; Motoyama Hideaki
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2009, 84, 84, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2009
    Japanese
  • Constituent elements of soluble particles recent glacial cycles exhibited in the Dome Fuji ice core (Antarctica)
    Iizuka Yoshinori; Suzuki Toshitaka; Sakurai Toshimitsu; Hirabayashi Motohiro; Miyake Takayuki; Motoyama Hideaki; Fujii Yoshiyuki; Hondoh Takeo
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2009, 83, 83, The Japanese Society of Snow and Ice / Japan Society for Snow Engineering, 2009
    Japanese
  • Antarctic sea ice extent during the Holocene reconstructed from inland ice core evidence
    Yoshinori Iizuka; Takeo Hondoh; Yoshiyuki Fujii
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 113, D15, Aug. 2008, [Peer-reviewed]
    English, Scientific journal
  • A relationship between ion balance and the chemical compounds of salt inclusions found in the Greenland Ice Core Project and Dome Fuji ice cores
    Yoshinori Iizuka; Shinichiro Horikawa; Toshimitsu Sakurai; Sigfus Johnson; Dorthe Dahl-Jensen; Jørgen Peder Steffensen; Takeo Hondoh
    Journal of Geophysical Research Atmospheres, 113, 7, Blackwell Publishing Ltd, 16 Apr. 2008, [Peer-reviewed]
    English, Scientific journal
  • A relationship between ion balance and the chemical compounds of salt inclusions found in the Greenland Ice Core Project and Dome Fuji ice cores
    Yoshinori Iizuka; Shinichiro Horikawa; Toshimitsu Sakurai; Sigfus Johnson; Dorthe Dahl-Jensen; Jorgen Peder Steffensen; Takeo Hondoh
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 113, D7, Apr. 2008, [Peer-reviewed]
    English, Scientific journal
  • Water soluble aerosols during glacial and interglacial climate reconstructed from bipolar ice cores
    Sakurai Toshimitsu; Ohno Hiroshi; Iizuka Yoshinori; Horikawa Shinichirou; Aoki Teruo; Johnsen Sigfus; Dahl-Jensen Dorthe; Steffensen J.P.; Hondoh Takeo
    Abstracts of Annual Meeting of the Geochemical Society of Japan, 55, 422, 422, GEOCHEMICAL SOCIETY OF JAPAN, 2008
    過去数十万年間における氷期・間氷期サイクルの詳細な情報は、南極やグリーンランド氷床の頂上で鉛直に掘られた氷床コアから復元できる。氷期から間氷期へ気候が急激に変化する引き金は、北半球の日射量の増加であると考えられた。しかし、日射量の変化が、地球の気候に影響を与えることは間違いないが、地球システムの複雑な現象が絡み合っているため、日射量の変化に応答する地表面の気候変動を詳細に見積もることは難しい。それを見積もるためにはまず、過去の大気成分を氷コアから復元して、日射量が地表面まで伝達する過程を氷期と間氷期について計算する（放射強制力）必要がある。本研究は、氷コアに含まれる微粒子の数密度・化学組成を融かさずに測定し、氷期・間氷期における水溶性エアロゾルの詳細を復元することを目的とし、エアロゾルによる氷期・間氷期の放射強制力を明らかにすることを目指すものである。
  • Antarctic sea ice extent during the Holocene reconstructed from inland ice core evidence
    Yoshinori Iizuka; Takeo Hondoh; Yoshiyuki Fujii
    Journal of Geophysical Research Atmospheres, 113, 15, Blackwell Publishing Ltd, 2008, [Peer-reviewed]
    English, Scientific journal
  • Aerosol flux variation on the East Antarctic Plateau during the past 720,000 years
    Goto-Azuma Kumiko; Hirabayashi Motohiro; Miyake Takayuki; Uemura Ryu; Kohno Mika; Motoyama Hideaki; Fujii Yoshiyuki; Iizuka Yoshinori; Horikawa Shinichiro; Suzuki Toshitaka; Igarashi Makoto; Satow Kazuhide; Suzuki Keisuke; Fukuoka Takaaki; Fujita Koji; Yoshida Naohiro; Watanabe Okitsugu
    Preprints of the Annual Conference, Japanese Society of Snow and Ice, 2007, 18, 18, THE JAPANESE SOCIETY OF SNOW AND ICE, 2007
    Japanese
  • High-time resolution analysis of dust in the Dome Fuji deep ice core, Antarctica: relationship between dust and calcium ion
    Miyake Takayuki; Iizuka Yoshinori; Tatenuma Takuya; Yanagisawa Takahiro; Sano Kiyofumi; Uemura Ryu; Hondoh Takeo; Fujii Yoshiyuki
    Preprints of the Annual Conference, Japanese Society of Snow and Ice, 2007, 177, 177, THE JAPANESE SOCIETY OF SNOW AND ICE, 2007
    Japanese
  • A record of dust concentration variation in the Dome Fuji deep ice cores, Antarctica
    Miyake Takayuki; Fujii Yoshiyuki; Goto-Azuma Kumiko; Iizuka Yoshinori; Igarashi Makoto; Uemura Ryu; Kohno Mika; Satow Kazuhide; Suzuki Keisuke; Suzuki Toshitaka; Hirabayashi Motohiro; Fukuoka Takaaki; Fujita Koji; Horikawa Shinichiro; Motoyama Hideaki; Yoshida Naohiro; Watanabe Okitsugu
    Preprints of the Annual Conference, Japanese Society of Snow and Ice, 2007, 101, 101, THE JAPANESE SOCIETY OF SNOW AND ICE, 2007
    Japanese
  • Na2SO4 and MgSO4 salts during the Holocene period derived by high-resolution depth analysis of a Dome Fuji ice core
    Yoshinori Iizuka; Takeo Hondoh; Yoshiyuki Fujii
    JOURNAL OF GLACIOLOGY, 52, 176, 58, 64, 2006, [Peer-reviewed]
    English, Scientific journal
  • Na+ concentration in snow and ice of the Dome Fuji region as a proxy of sea ice extent
    Iizuka Yoshinori; Hondoh Takeo; Fujii Yoshiyuki
    Preprints of the Annual Conference, Japanese Society of Snow and Ice, 2006, 211, 211, THE JAPANESE SOCIETY OF SNOW AND ICE, 2006
    Japanese
  • Ice core processing at Dome Fuji Station, Antarctica
    FUJITA SHUJI; AZUMA KUMIKO; IGARASHI MAKOTO; AZUMA NOBUHIKO; KAMEDA TAKAO; IIZUKA YOSHINORI; SAITO TAKESHI; SHOJI HITOSHI; TAKATA MORIMASA; TANAKA YOICHI; SUZUKI KEISUKE; SUZUKI TOSHITAKA; FUJII YOSHIYUKI; FUJITA KOJI; FURUSAKI ATSUSI; HONDOH TAKEO; MOTOYAMA HIDEAKI; WATANABE OKITSUGU
    Preprints of the Annual Conference, Japanese Society of Snow and Ice, 2006, 210, 210, THE JAPANESE SOCIETY OF SNOW AND ICE, 2006
    Japanese
  • Fluctuations in Antarctic sea-ice extent during the past 30 kyr.
    Iizuka, Y; Hondoh, T; Fujii, Y
    Earth and Planetary Science Letters., 2006, [Peer-reviewed]
  • SO42- minimum in summer snow layer at Dome Fuji, Antarctica, and the probable mechanism
    Y Iizuka; Y Fujii; N Hirasawa; T Suzuki; H Motoyama; T Furukawa; T Hondoh
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 109, D4, Feb. 2004, [Peer-reviewed]
    English, Scientific journal
  • Stratigraphic analysis of Dome Fuji Antarctic ice core using an optical scanner
    M Takata; Y Iizuka; T Hondoh; S Fujita; Y Fujii; H Shoji
    ANNALS OF GLACIOLOGY, VOL 39, 2004, 39, 467, 472, 2004, [Peer-reviewed]
    English, Scientific journal
  • High-time-resolution profiles of soluble ions in the last glacial period of a Dome Fuji (Antarctica) deep ice core
    Y Iizuka; M Takata; T Hondoh; Y Fujii
    ANNALS OF GLACIOLOGY, VOL 39, 2004, 39, 452, 456, 2004, [Peer-reviewed]
    English, Scientific journal
  • Chemical characteristics in a 22-m ice core on the Belukha Glacier, Russia
    Iizuka Yoshinori; Fujita Koji; Matoba Sumito; Fujii Yoshiyuki; Matsuki Kenichiro; Kohno Mika; Aizen Vladimir B
    Polar meteorology and glaciology, 18, 114, 120, National Institute of Polar Research, 2004, [Peer-reviewed]
    English, Scientific journal, To better understand how the chemical composition of a glacier in an inland continental region relates to the local climate, we collected ice core samples from the Belukha Glacier, Russia, in July 2001. We analyzed the samples for pH, anions, and cations. The primary soluble ions were SO42-, NO3-, NH4+, Ca2+, and HCOO-. Moreover, we argue the following. 1) Ca2+ and its equivalent SO42-+ NO3- likely originated from terrestrial dust such as soil. 2) HCOO- and its equivalent NH4+ likely originated from vegetation and/or biomass burning. 3) The remaining SO42-+NO3- and NH4+ likely originated from livestock, commercial fertilizers, and natural fertilizers. 4) The NH4+ concentration was low when there was no contribution from vegetation and/or biomass burning.
  • Regional characteristics of surface snow chemistry at East Dronning Maud Land, Antarctica
    Motoyama, H; K. Kamiyama; T. Shiraiwa; T. Saito; T. Kameda; N. Azuma; S. Fujita; Y. Fujii; K. Suzuki; T. Yamada; T. Suzuki; Y. Iizuka; T. Furukawa; K. Nishimura; S. Kanamori; O. Watanabe
    Seventh International Symposium on Antarctic Glaciology, 11, 01 Aug. 2003
    English, International conference proceedings
  • 第二期Dome Fuji氷床コアプロジェクトに用いる光学層位記録装置の開発
    高田 守昌; 飯塚 芳徳; 庄子 仁; 宮本 淳; 本堂 武夫; 藤田 秀二; 藤井 理行; Morimasa Takata; Yoshinori Iizuka; Hitoshi Shoji; Atsushi Miyamoto; Sepp Kipfstuhl; Takeo Hondoh; Shuji Fujita; Yoshiyuki Fujii
    南極資料 = Antarctic Record, 47, 3, 328, 337, 2003, [Peer-reviewed]
    Japanese, Scientific journal, 第二期ドームふじ氷床コアプロジェクトの現場解析において,簡便に光学層位を記録するため,専用装置を開発した.この装置は,二次元的な光の散乱強度を氷床コアサンプルの深さ方向に沿って連続的に測定する.我々は,この装置のハードウェアおよび制御ソフトウェアを開発した.この結果,経験のないオペレーターでも容易に測定可能な,自動測定装置が完成した.測定速度は5mm/sを想定しており,この場合,現場処理解析の基本長である1.5mのサンプルを約6分間で測定可能である.この装置は第44次越冬隊が南極ドームふじ観測拠点に搬入し,第45次夏隊から始まる深層コア掘削の現場解析処理に使用される予定である.An optical scanner for stratigraphical study was developed for the Dome Fuji ice core project II. The optical scanner measures two-dimensional light scattering intensities and records optical structures of ice cores. We developed the scanner hardware and control software. The line scanner is controlled by a personal computer and is constructed for automatic measurement. The sliding speed of the scanner is about 5mm per second and, therefore, one ice core sample with a standard length for our sample processes (1.5m long) can be measured within about six minutes. The line scanner was transported to Dome Fuji Station, Antarctica, by the wintering party of the 44th Japanese Antarctic Research Expedition (JARE-44), and will be used for Dome Fuji II ice core measurement by the JARE-45 summer party and successive parties.
  • Spatial distribution of chemical tracers in snow along the route from the coast to 1000km inland at east Dronning Maud Land, Antarctica
    Suzuki, T; Y. Iizuka; T. Furukawa; K. Matsuoka; K. Kamiyama; O. Watanabe
    Chinese Journal of Polar Science, 14, 48-56, 2003, [Peer-reviewed]
  • Distribution of sea salt components in snow cover along the traverse route from the coast to Dome Fuji station 1000 km inland at east Dronning Maud Land, Antarctica
    T Suzuki; Y Iizuka; K Matsuoka; T Furukawa; K Kamiyama; O Watanabe
    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY, 54, 4, 407, 411, Sep. 2002, [Peer-reviewed]
    English, Scientific journal
  • Glaciological data collected by the 39th and 40th Japanese Antarctic Research Expedition during 1998-2000
    Furukawa, T; T. Yamada; K. Suzuki; T. Suzuki; K. Matsuoka; K. Horikawa; E. Murakata; K. Yasugahira; Y. Iizuka
    JARE Data Reports, No. 267 (Glaciology 29), 01 Apr. 2002
    English, Research institution
  • 東南極、ハムナ氷瀑底面氷の結晶方位分布
    飯塚 芳徳; 渡辺 興亜
    Bulletin of glaciological research, 19, 59, 62, 2002, [Peer-reviewed]
    Scientific journal
  • Ratios of Mg2+/Na+ in snowpack and an ice core at Austfonna ice cap, Svalbard, as an indicator of seasonal melting
    Y Iizuka; M Igarashi; K Kamiyama; H Motoyama; O Watanabe
    JOURNAL OF GLACIOLOGY, 48, 162, 452, 460, 2002, [Peer-reviewed]
    English, Scientific journal
  • Formation processes of a pocket consisting of bubble-free ice in Hamna ice cliff, Soya Coast, East Antarctica
    Iizuka Yoshinori; Satake Hiroshi; Watanabe Okitsugu
    Polar meteorology and glaciology, 16, 53, 60, 2002, [Peer-reviewed]
    English, Scientific journal, To clarify the basal hydrology of Soya drainage, East Antarctica, we studied the formation processes of a pocket consisting of bubble-free ice in Hamna ice cliff, Soya Coast by using stable isotope ratios (δ^<18>O andδD). The stable isotopes of this bubble-free ice are almost the same values withoutδ-value fluctuations as those from Rayleigh-type fractionation; isotopically, the bubble-free ice was heavier by 3.8 and 27‰ for δ^<18>O and δD, respectively, than the neighboring bubbly ice. These results suggest that the pocket was formed by meltwater refreezing during the discharge of water to the lower reach under the Soya drainage. Meltwater under the Soya drainage is considered to have flowed through R-channels.
  • 1996・1997年のカムチャツカ半島カレイタ氷河における流出および水文化学的特性
    松元 高峰; 飯塚 芳徳; 兒玉 裕二; Muravyev Yaroslav D; 鈴木 啓助
    Bulletin of glaciological research, 19, 71, 80, 2002, [Peer-reviewed]
    Scientific journal
  • 雪氷コアの処理方法の改良
    神山 孝吉; 飯塚 芳徳; Kokichi Kamiyama; Yoshinori Iizuka; Bernhard Stauffer
    南極資料 = Antarctic Record, 45, 2, 171, 184, 2001, [Peer-reviewed]
    Japanese, Scientific journal, 雪氷コアの解析には, 初期に様々な処理作業を必要とする。特に化学解析の場合には試料を解析機器に導入する前の処理作業が不可欠であり汚染除去の方法など従来から検討されてきた。ここでは低温実験室で行っていた作業の一部を常温実験室で行い, 処理作業環境の向上を目指した。極地研究所の低温実験室に冷凍保管していた雪氷コアの切断作業を常温実験室に設置した温度コントロールチェンバーを利用して行った。チェンバー内部に小型のコア切断機器を設置し試料を整形した後, 直ちにコア密度を測定した。融解後試料の電気伝導度などを測定し, ラベルを記載した専用容器に保管し, その後トリチウム濃度などの計測に供した。コア試料の切断・密度測定・融解・電気伝導度測定・融解保存容器への保管整理で5m/6時間/一人の作業量効率であることを確認した。また冷凍状態での雪氷コア試料を, 常温実験室で深さ方向の連続融解と試料のサンプル容器への自動分注方法について検討した。実際のコア試料を連続融解しイオン分析用に専用の容器への分注を行ったが, 10試料/15cm/30分/一人の作業量を必要とした。なお作業については複数の人間が携わる必要はなく処理作業効率が上昇し, 測定結果は十分満足できる精度であった。Ice core analyses start with the processing of ice cores. Especially for chemical analyses, pre-treatments for introducing the samples to the measuring instruments without contamination is essential. Part of processing can be carried out under a normal laboratory instead of the cold one to improve the efficiency of processing the core samples. The ice core cutting was carried out in a small chamber, with temperature control, installed in a normal laboratory. The ice core sample was cut with a small instrument in the chamber and melted after the determination of solid bulk density. The melted samples were stored after labeling for the planned measurements, such as HTO measurements. The core processing including cutting in the chamber, measurement of bulk density and electrical conductivity before the storage of melted samples with labeling, were carried out at the rate of 5m/(6 hours・person). The continuous melting and sampling procedures for the ice core sample toward the depth direction are also discussed. Continuous melting with continuous sampling for measurement of ion chromatography was carried out on 10 samples/(15cm・30min・person). The processing was efficient for the delicate sampling, and the data obtained in the procedure was supported by those obtained with normal procedure.
  • The reduction of chloride ion concentration in basal ice near Hamna Icefall, East Antarctica
    Iizuka Yoshinori; Satake Hiroshi; Watanabe Okitsugu
    Polar meteorology and glaciology, 15, 107, 113, National Institute of Polar Research, 2001, [Peer-reviewed]
    English, Scientific journal, The present paper mainly discusses chloride ions (Cl^-) in debris-laden basal ice near Hamna Icefall, Queen Maud Land, East Antarctica. The basal ice consists of alternating layers of bubble-free and bubbly ice of the order of mm to cm in thickness. Detailed analyses of Cl^- and stable isotopes (δ^<18>O and δD) on the alternating layers were performed. The Cl^- concentrations in the bubble-free ice layers and in the bubbly ice layers whose isotopic fluctuations decrease from neighboring bubble-free ice layers are reduced compared to those in the bubbly ice layers having quasi-neutral values on the isotopic profile. The reduction of Cl concentration in frozen ice compared to that in pre-freezing water was also observed from an experiment on ion fractionation by freezing. These results suggest that the bubble-free ice layers and the bubbly ice layers whose isotopic fluctuation is decreased from that in neighboring bubble-free ice layers were formed by melt-refreezing processes. The reduction of Cl concentration in the basal ice is considered to be an indicator to distinguish whether the basal ice has experienced melt-refreezing or not.
  • Regional distribution of chemical tracers in snow cover along the route from S16 to Dome Fuji Station, east Dronning Maud Land, Antarctica
    Suzuki Toshitaka; Iizuka Yoshinori; Furukawa Teruo; Matsuoka Kenichi; Kamiyama Kokichi; Watanabe Okitsugu
    Polar meteorology and glaciology, 15, 133, 140, National Institute of Polar Research, 2001, [Peer-reviewed]
    English, Scientific journal, We show and discuss the regional distributions of Cl^-, Na^+, SO_4^2,NO_3 and ^7Be concentrations in snow cover along the route from S16 to Dome Fuji Station in east Dronning Maud Land, Antarctica. The concentrations of Cl and Na^+ at the coast exponentially decreased with distance from the coast up to 200km inland. Between 200-1000km inland, the concentrations of Na^+ were nearly constant. On the other hand, the concentrations of Cl increased with distance beyond 750km inland. Furthermore, the contribution factors between Cl and Na^+ decreased and the Cl/Na^+ ratio and the nssCl^-/Cl^- ratio increased toward the interior of the continent. These results indicate that sea salt aerosols are transported from the coastal region toward the inland region of the Antarctic continent, and that a source of Cl other than sea salt exists in the inland plateau of Antarctica. The concentrations of SO_4^2,NO_3 and ^7Be in snow were relatively high in the coastal region and the inland plateau region compared with those in the katabatic-wind region.
  • Regional characteristics of chemical constituents in surface snow, Arctic cryosphere
    Motoyama Hideaki; Watanabe Okitsugu; Kamiyama Kokichi; Igarashi Makoto; Azuma Kumiko; Fujii Yoshiyuki; Iizuka Yoshinori; Matoba Sumito; Narita Hideki; Kameda Takao
    Polar meteorology and glaciology, 15, 55, 66, National Institute of Polar Research, 2001, [Peer-reviewed]
    English, Scientific journal, Surface snow observations were carried out on many glaciers in the Arctic. The observational sites were in Svalbard, Severnaya Zemlya, Greenland and arctic Canada. The seasonal variations of chemical constituents in snowfall remained in the surface snow on the central Greenland ice sheet where the effect of snowmelt was weak. Conversely, the chemical constituents in the snow layer changed with infiltration of melt water on the Svalbard glacier where strong snowmelt occurred, even in high latitudes. But in general, specific regional characteristics remained in all the glaciers. The concentrations of ions in snow were significantly decreased, because of percolation of melt water. But the ratio of NO_3 to Cl still had unique regional characteristic values.
  • 内陸旅行：夏期ドーム旅行
    古川晶雄; 鈴木利孝; 松岡健一; 五十嵐賢二; 草谷洋光; 飯塚芳徳
    日本南極地域観測隊第40次隊報告, 369, 386, 01 Apr. 2000
    Japanese, Research institution
  • スバールバル諸島アウストフォンナ氷帽頂上における融解による積雪中化学主成分の流出
    飯塚 芳徳; 五十嵐 誠; 渡辺 幸一; 神山 孝吉; 渡辺 興亜
    雪氷, 62, 3, 245, 254, The Japanese Society of Snow and Ice, 2000, [Peer-reviewed]
    Japanese, Scientific journal, Snowpack samples were collected from the dome of Austfonna ice cap, Svalbard, in the spring of 1998. Snowpack samples were analyzed for anions, cations, pH, EC and δ18O. The results showed that the concentration levels in melted and refrozen snowpack were much lower than those in non-melted snowpack. It is suggested that the ions were flushed out from the snowpack during the thaw. A clear difference of Mg2+/Na+ ratio between the melting experienced snowpack (0.03±0.02) and the non-melted snowpack (0.11±0.02) was detected. We propose that the Mg2+/Na+ ratio become an indicator to distinguish whether firn in the ice core has experienced of melting or not.
  • Chemical characteristics of basal ice near Hamna Icefall, East Antarctica
    Iizuka Yoshinori; Igarashi Makoto; Shiraiwa Takayuki; Naruse Renji; Yamada Tomomi; Watanabe Okitsugu
    Polar meteorology and glaciology, 14, 8, 15, National Institute of Polar Research, 2000, [Peer-reviewed]
    English, Scientific journal, Debris-laden basal ice is exposed along an ice cliff (about 30m high) near Hamna Icefall, Soya Coast, East Antarctica. The basal ice about 6.8m thick can be divided into an upper part (5.5m) and a lower part (1.3m) based on stratigraphic features. Major dissolved ions of the basal ice are probably composed of eight species (Na^+, K^+, Mg^<2+>, Ca^<2+>, Cl, SO_4^2,NO_3 and HCO_3). Almost all Na^+, K^+, Mg^<2+>, Ca^<2+>, SO_4^2 and HCO_3 in the basal ice are considered to have originated from chemical erosion of rock minerals at the base of the ice sheet. According to a calculation of ion composition, the primary rock mineral dissolved in the basal ice is considered to be carbonate.
■ Other Activities and Achievements
■ Books and other publications
  • アイスコア 地球環境のタイムカプセル
    飯塚芳徳
    Mar. 2010, [Joint work]
  • なぞの宝庫 南極大陸
    飯塚芳徳
    2008, [Joint work]
■ Syllabus
  • 古海洋学特論, 2024年, 修士課程, 環境科学
  • 地球雪氷学実習Ⅱ, 2024年, 修士課程, 環境科学院
  • 古環境学基礎論, 2024年, 修士課程, 環境科学
  • 地球雪氷学実習Ⅰ, 2024年, 修士課程, 環境科学院
  • 氷河・氷床学特論, 2024年, 修士課程, 環境科学院
  • 大学院共通授業科目（教育プログラム）：南極学, 2024年, 修士課程, 大学院共通科目
  • 古環境学基礎論, 2024年, 修士課程, 環境科学院
  • 地球雪氷学基礎論, 2024年, 修士課程, 環境科学院
  • 一般教育演習(ﾌﾚｯｼｭﾏﾝｾﾐﾅｰ), 2024年, 学士課程, 全学教育
■ Research Themes
  • Investigation of the Impact on Climate Change via a 4-Dimensional Assessment of Material Circulation and Atmospheric Oxidation Capacity in the Antarctic Troposphere
    Grants-in-Aid for Scientific Research
    01 Apr. 2024 - 31 Mar. 2028
    原 圭一郎; 平林 幹啓; 高島 久洋; 的場 澄人; 飯塚 芳徳; 須藤 健悟; 竹中 規訓; 石野 咲子; 矢吹 正教
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Fukuoka University, 24H00757
  • 氷床コア中の過酸化水素の酸素同位体組成を用いた産業革命前の対流圏オゾン濃度の復元
    科学研究費助成事業
    01 Apr. 2023 - 31 Mar. 2027
    石野 咲子; 飯塚 芳徳
    日本学術振興会, 基盤研究(B), 金沢大学, 23K28212
  • Reconstruction of particle size distribution of sulfate aerosols from pre-industrial to present using an ice core
    Grants-in-Aid for Scientific Research
    01 Apr. 2023 - 31 Mar. 2027
    飯塚 芳徳; 植村 立; 大島 長
    本研究の目的は世界で最も沈着エアロゾルが保存されているグリーンランド南東部のアイスコアを用いて、産業革命前から現在までの硫酸エアロゾルの沈着フラックスと粒径分布を復元することである。また、過去の硫酸エアロゾル粒子の化合物状態や硫黄同位体比を分析し、過去の硫酸エアロゾルの粒径分布がどのようなメカニズムで変化するのかを明らかにする。
    これまで、過去の硫酸エアロゾルの分級データは、申請者らによる1973-75年と2010-12年の0.4マイクロメートルを区別したデータしか存在しない。本研究では、現在の大気エアロゾル分級で用いられる低圧カスケードインパクタ（東京ダイレック社 MAIS9）を導入し、アイスコアから過去の硫酸エアロゾルを多段のフィルターに分画し、より細かく粒子径を分級する装置を開発している。2024年3月時点でコンタミ除去がほぼ終わり、テストケースとしてグリーンランド南東部のアイスコアの1851年夏の氷試料を用いて、硫酸イオン濃度の分級をはじめた。その結果、粒径が0.24マイクロメートル付近で硫酸エアロゾルのピークがあること、この分布は現在の硫酸エアロゾルの粒径分布と似ていることが分かった。これまで、0.2マイクロメートルの大きさの粒径をアイスコアから分析した例はほとんどなく、より小さいエアロゾルの重要性を認識した。これらの研究成果を日本雪氷学会の全国大会で発表した。今後、人為硫黄最盛期など他の時代の分析を進めていく予定である。
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 23H00511
  • 氷床コア中の過酸化水素の酸素同位体組成を用いた産業革命前の対流圏オゾン濃度の復元
    科学研究費助成事業
    01 Apr. 2023 - 31 Mar. 2027
    石野 咲子; 飯塚 芳徳
    日本学術振興会, 基盤研究(B), 金沢大学, 23H03522
  • Modulation of Polar Ice Sheet Dynamics by Aerosols: Insights from Ice Core Analyses and Radar Soundings
    Grants-in-Aid for Scientific Research
    Apr. 2024 - Mar. 2027
    藤田 秀二; 平林 幹啓; 飯塚 芳徳; 津滝 俊; 中澤 文男; 大野 浩; 東 久美子
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), National Institute of Polar Research, 24H00760
  • アイスコアに含まれる過去の有機物エアロゾル粒子の粒径と化合物組成の測定方法の開発
    科学研究費助成事業
    30 Jun. 2023 - 31 Mar. 2025
    飯塚 芳徳
    本研究はラマン分光器に新しいラマンレーザーを導入し、過去の有機物エアロゾル粒子の粒径や化合物状態を分析する手法の確立を目的とする。その手法を、世界で最も沈着エアロゾルが保存されているグリーンランド南東部のアイスコアに適用して、産業革命前から現在までの有機物エアロゾルの粒径と組成を復元することである。
    本研究ではすでに申請者が確立してきたアイスコアから過去のエアロゾル粒子を抽出する手法を改良し、有機物クリーンにするために孔径0.1マイクロメートルの有機物除去フィルターや炭素フリーの配管に改良し、有機物的にクリーンな乾燥空気を作成した。次に、エアロゾルをメンブレンフィルターではなく、鏡面金属板などラマン不活性の試料抽出台を用いる。こういった装置の改良により、アイスコアに含まれる過去の有機物エアロゾルの粒径と化合物組成を分析する手法を開発した。また、有機物の検出に強いとされる赤色のラマンレーザーを顕微ラマン分光器に導入した。中央アジアヒマラヤのアイスコアをクリーンな状態で昇華させ、氷に含まれる直径数マイクロメートル程度の不純物粒子を抽出し、不純物のラマン分析を実施した。その結果、有機物と思われる波長1300から1400㎝-1のピークを検出した。この波長はCH3もしくはCH2の結合を示す可能性が高く、この微粒子が有機物を有する可能性が極めて高いことを示唆している。これはアイスコアに含まれる数マイクロメートルの微粒子を検出できたことを示す成果である。ただ、この波長をもつ有機物がどのような化合物なのかが不明であり、今後、いくつかの有機物の標準試料のラマンスペクトルを測定し、有機物の同定を進めていく必要がある。
    日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 23K18516
  • Study on physics and layers of ice cores containing information of climate change over the past 720 k-years, and study on the "oldest ice"
    Grants-in-Aid for Scientific Research
    11 Jun. 2018 - 31 Mar. 2023
    藤田 秀二; 平林 幹啓; 飯塚 芳徳; 大野 浩
    当初計画に従い、以下の項目の研究を遂行した。
    Ⅰ．アイスコアの物理層位の計測：①ミリ波誘電率テンソルの計測を2400m深から深い側に延伸した。② ①とあわせ、結晶Ｃ軸方位の直接計測とを実施し比較を実施した。③水平面内での誘電テンソルの主軸２成分の差を明らかにする分析を実施した。④ミリ波誘電テンソルにかかる研究成果の論文化を開始し、2021年4月と11月にそれぞれ投稿し、前者は出版に至った。後者は公開査読論文として出版され、本報告執筆時には公開査読が継続されている。
    Ⅱ．連続融解計測装置系（CFA）を用いたアイスコアの化学層位計測：①2019年度までに開発した小型融解ヘッドの試験を重ねている。ただし、ドームふじアイスコアの分析・消費については、他研究分野との調整の必要が生じ、この計測実施を最終年度に延期した。②ドームふじアイスコアの中層のアイスコアとしては、約570m深～600m深の試料についての連続解析を実施した。また同様に、ドームふじ近傍で2017/2018年に新たに掘削された152m長の浅層コアについて、約75m深よりも浅い深度区間の計測を完了した。
    Ⅲ. 塩微粒子の層位にかかる研究：不純物の存在状態の検知計測を、ラマン分光散乱を用いて継続した。
    Ⅳ. アイスコアの信号形成にかかるプロセスにかかる研究：2020年度は、以下の２点についての研究を推進した。氷床に閉じ込められてから数百年程度以内の深度約100-120m深の気泡をラマン分光散乱で解析し、気泡中の酸素と窒素の分別比を実測した。
    このほか、ドームふじアイスコアの固体電気伝導度解析として前年度まで実施してきたDEPデータの解析、氷床探査用レーダの観測データとアイスコアデータとの比較、アイスコア間の気候変動イベントの年代差の抽出作業を、同期進捗に応じ随時実施した。
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (S), National Institute of Polar Research, 18H05294
  • Construction of world’s most reliable deposited-aerosol database on the Anthropocene (from 1850 to 2020)
    Grants-in-Aid for Scientific Research
    11 Jun. 2018 - 31 Mar. 2023
    飯塚 芳徳; 植村 立; 関 宰; 的場 澄人; 大島 長; 藤田 耕史; 大野 浩; 服部 祥平
    本プロジェクトの目的は産業革命から現在までの高確度エアロゾルデータベースの構築とアイスコアの新規分析手法から人新世の大気環境復元を高度化することである。最初の目的のために、グリーンランド南東ドームでの250mのアイスコア掘削した。2020年度では、コロナ禍でデンマークやグリーンランドは通年レベル3の渡航禁止下であり、2021年度（本年度）に計画を延期していた。2021年度もデンマークやグリーンランドは通年レベル3の渡航禁止下であり続けたが、4―7月に困難な状況のもとで掘削を決行し、250mのアイスコアの取得に成功した。11月にアイスコアが輸入され、2021年度末現在、そのアイスコアの初期解析を実施している。
    第2の目的達成のために、すでに本プロジェクトで公開済のエアロゾルデータを参考にしつつ、1)衛星による近過去の雲量との統計的解析（主担当：藤田）、2)氷晶核能測定装置の開発、3)ダストデータの高精度解読、4)電子顕微鏡による硝酸塩組成の復元（主担当：大野）、5）過酸化水素分析法の確立（主担当：服部）、6）硫酸エアロゾル中の酸素同位体比を用いた大気酸化力の復元（主担当：服部）、7）メタンスルホン酸による海氷面積・海洋生物活動の復元（主担当：的場）、8）過去の硫酸エアロゾルの粒径復元、9）ラマン分析によるアンモニウム塩・硝酸塩の組成復元、10）放射光によるカルシウムエアロゾルの化合物同定のなどの分析に着手してきた。
    このうち、硫酸エアロゾル中の酸素同位体比を用いた大気酸化力の復元から、1980年以降の二酸化硫黄排出規制にもかかわらず、硫酸エアロゾルの減少が鈍化しているメカニズムを解明し、論文にまとめた。アンモニアなどのアルカリ性物質の増加による大気の酸性度低下が原因で、大気化学過程が変化し、結果的に硫酸生成効率が上昇することを突きとめた。今後の北極域の環境変動予測に重要な成果である。
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (S), Hokkaido University, 18H05292
  • Recent surface darkening and abrupt melting of Greenland ice sheet (SIGMA2)
    Grants-in-Aid for Scientific Research
    01 Apr. 2016 - 31 Mar. 2020
    Aoki Teruo
    In order to clarify the recent surface melting of the Greenland ice sheet, in-situ field observations, satellite remote sensing and numerical modelling were conducted. In the field observations, existing automatic weather station observations were continued and the data were published. Ice core samples were analyzed to characterize water vapor and mineral dust transport. In satellite remote sensing, we developed an algorithm to retrieve the snow and ice physical parameters using a non-spherical snow particle shape model and quantified the causes of ice sheet surface darkening. In numerical modelling, a regional meteorological model including the detailed processes of light-absorbing aerosols (LAA) was developed. A regional meteorological model including snow metamorphism was used to simulate the time and spatial variation of ice sheet surface melting. In addition, the radiative forcing due to LAA in the atmosphere and snow/ice was estimated by an earth system model.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), 16H01772
  • Sulfur and nitrogen isotopes in a single particle of sulfate and nitrate aerosols in polar ice cores
    Grants-in-Aid for Scientific Research
    01 Apr. 2016 - 31 Mar. 2019
    Iizuka Yoshinori; Uemura Ryu; Sano Yuji; Kagoshima Shogo; Ando Takuto
    In order to measure sulfur and nitrogen isotopes in a single particle of sulfate and nitrate aerosols in polar ice cores, we collected particles on a mesh from ice cores. Then, we measured sulfur isotopes of the single particles. As a result, the average isotope values are about 22 ‰, which is reasonable result for natural sulfate aerosols, however with large error of about 10 ‰.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 16K12573
  • Paleoenvironmental reconstruction using Alaskan permafrost ground ice
    Grants-in-Aid for Scientific Research
    01 Apr. 2016 - 31 Mar. 2019
    Ohno Hiroshi
    This study has attempted paleoenvironmental reconstruction using Alaskan ancient permafrost ground ice (14000 to 12300 B.P.).
    It has become evident that methane concentration and stable carbon isotope ratio of methane in the ground ice co-vary with temperature (stable oxygen isotope ratio of ice), indicating relation between methane productivity (formation pathway) and climate changes.
    Also, significantly high methanesulfonic acid concentrations were found even in the cold period (Younger Dryas) ice, indicating that near-shore region in the Alaskan Beaufort Sea may not have been completely filled by permanent sea ice at that time.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Kitami Institute of Technology, 16H05615
  • Evaluation of anthropogenic air temperature change by using past aerosols in a Greenlandic ice core.
    Grants-in-Aid for Scientific Research
    01 Apr. 2014 - 31 Mar. 2019
    Iizuka Yoshinori
    The Southeastern Greenland Dome (SE-Dome) has both a high elevation and a high accumulation rate (1.01 m w.e. yr-1), which are suitable properties for reconstructing past environmental changes with a high time resolution. For this study, we measured the major ion fluxes in a 90-m ice core drilled from the SE-Dome region in 2015, and present the records of annual ion fluxes from 1957 to 2014. From 1970 to 2010, the trend of non-sea-salt (nss) SO42- flux decreases, whereas that for NH4+ increases, tracking well with the anthropogenic SOx and NH3 emissions mainly from North America. The result suggests that these fluxes reflect histories of the anthropogenic SOx and NH3 emissions. In contrast, the decadal trend of NO3- flux differs from the decreasing trend of anthropogenic NOx emissions.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 26257201
  • Climate analysis using sulfur stable isotope ratio from Antarctic snow and ice core
    Grants-in-Aid for Scientific Research
    01 Apr. 2014 - 31 Mar. 2018
    UEMURA Ryu; HIRABAYASHI Motohiro; IIZUKA Yoshinori
    Sulfate aerosols affect Earth’s radiative forcing through direct and indirect effects. Ice core data suggest minor changes in sulfate aerosols over the glacial cycles. However, the variations of source contributions of sulfate aerosols remain unclear. In this project, to estimate the changes in source contributions of sulfate aerosols in Antarctica, we analyzed sulfur isotopic ratios of surface snow and ice core. Sulfur isotope ratio of present-day surface snow over East Antarctica shows that the effects of the transport process are small, and major source of present-day sulfate aerosol is marine biogenic activity. The ice core data show that the sulfur isotopic ratio increased from the last glacial period to Holocene.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, University of the Ryukyus, 26550013
  • Chemical compositions of soluble inclusions in cold snowfall
    Grants-in-Aid for Scientific Research
    01 Apr. 2014 - 31 Mar. 2016
    Iizuka Yoshinori; NAKAMURA Kazuki; Sato Tomonori
    In this study, we had aerosol and snow precipitation sampling at same time in Tomamu basin, and then measured chemical compositions of solid particles both of insoluble and soluble materials. This study produce a first approach that direct comparison of chemical components between dry and wet depositions at same time in same place. We will discuss the difference of chemical components between dry and wet depositions.
    As a result, the chemical components between inclusions in snow and aerosols are diffrent. Especially, inclusions in snow have many NaCl not but aerosols have less NaCl particles. Also, inclusions in diamond dust have less NaCl. These diffrences are probably due to the diffrence of origins of inclusion.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 26610147
  • Warming events and their impacts during the past 150,000 years viewed from Greenland ice
    Grants-in-Aid for Scientific Research
    01 Apr. 2010 - 31 Mar. 2016
    Azuma Kumiko; KAWAMURA Kenji; FUJITA Shuji; UETAKE Jun; MOTOYAMA Hideaki; HIRABAYASHI Motohiro; KOBASHI Takuro; TAKAMURA Chikako; KURAMOTO Takayuki; SEGAWA Takahiro; AOKI Shuji; AZUMA Nobuhiko; IIZUKA Yoshinori
    We analyzed the ice core drilled under the international project North Greenland Eemian Ice Drilling. The air temperature during the warmest period of Eemian interglacial was warmer than the present by 8℃±４℃, which caused extensive surface melt in north Greenland. The thickness of the northwest Greenland ice sheet decreased by 400±250ｍ during 6000 years, which was much smaller than that had been expected. Mass loss of Antarctic ice sheet should have played a role in sea-level rise during the Eemian. Variations of methane, nitrous oxide, noble gases in the air extracted from the ice core, and those of ionic species and bacterial cell concentrations in ice provided us with valuable information on changes in atmospheric circulation, vegetation, microbial activities, mean ocean temperature etc during the warm periods and abrupt warming events.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (S), National Institute of Polar Research, 22221002
  • Physical processes of formation of climate signals in deposited snow in inland plateau of the Antarctic Ice Sheet
    Grants-in-Aid for Scientific Research
    01 Apr. 2012 - 31 Mar. 2015
    FUJITA Shuji; HACHIKUBO Akihiro; IIZUKA Yoshinori; HORI Akira; KAWAMURA Kenji; KOBASHI Takuro; KIM Koui; KIPFSTUHL Josef
    In order to better understand the physical processes of formation of climate signals in deposited snow in inland plateau of the Antarctic Ice Sheet of polar firn, firn cores from Dome Fuji, Antarctica and NEEM Camp, Greenland, were investigated. Layers with initially smaller density and smaller geometrical anisotropy deform preferentially throughout the densification process due to textural effects. Second, layers having a higher concentration of chloride and/or fluoride ions deform preferentially during a limited period from the ice sheet surface until smoothing out of layered ions by diffusion. We hypothesize that these ions softened firn due to modulation of dislocation movement. Moreover, firn differs markedly between the sites in terms of strength of geometrical anisotropy, mean rate of densification, and density fluctuation. We hypothesize that these differences are caused by textural effects resulting from differences in depositional conditions within various spatial scales.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), National Institute of Polar Research, 24241007
  • Past atmospheric characteristics of glacial and interglacial periods reconstructed from aerosol compositions preserved in bipolar ice cores.
    Grants-in-Aid for Scientific Research
    2011 - 2012
    IIZUKA Yoshinori
    Sulphate aerosols, particularly micron-sized particles of sulphate salt and sulphate-adhered dust, can act as cloud condensation nuclei, leading to increased solar scattering. Evidence for sulphate-climate coupling in the current era has not been found, but may be revealed in the long-term sulphate record from polar ice cores. Melted ice-core samples have previously provided only sulphate-ion concentrations, which may be due to sulphuric acid. We present profiles of sulphate-salt fluxes over the past 300,000 years from the Dome Fuji ice core in inland Antarctica. Results show the sulphate-salt flux correlates inversely with temperature, suggesting a climatic coupling between particulate sulphur and temperature. Although based on a model with serious uncertainties when applied to the ice core record, this analysis indicates that the glacial-to-interglacial decrease in sulphate would lessen the aerosol indirect effects on cloud albedo, leading to an Antarctic warming of 0.1 to 5.2 K.
    Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (A), Hokkaido University, Principal investigator, Competitive research funding, 23681001
  • Study on the global environmental change with the various time scales by the various analysis of ice cores
    Grants-in-Aid for Scientific Research
    2009 - 2012
    MOTOYAMA Hideaki; AZUMA Kumiko; IIZUKA Yoshinori; UEMURA Ryu; SUZUKI Kazue; OHNO Hiroshi; KAWAMURA Kenji; FUJITA Shuji; MIYAKE Takayuki; HIRABAYASHI Motohiro; KURAMOTO Takayuki
    An ice core was drilled to a depth of 3035 m at the Dome Fuji station in Antarctica. Ice cores contain records of global environmental changes dating back to 720,000 years into the past. The age of the ice core was estimated with high accuracy, and a global standard record of climate and environmental changes was soon published. Further, a study of the mechanism of global environmental changes was developed. Results indicate that sulfate aerosol contributed to temperature change during the glacial-interglacial period. In addition, we clarified that the origin of the sulfate was not only the sea biological activity but also dust.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (S), National Institute of Polar Research, Coinvestigator not use grants, Competitive research funding, 21221002
  • reconstruction of aerosol components in Dome Fuji ice core recent 720kyr
    Grants-in-Aid for Scientific Research(若手研究(B))
    2009 - 2010
    Yoshinori IIZUKA
    we reconstructed past aerosol components recent 720kyrBP by using Dome Fuji ice core. As a result, primary components in soluble aerosols were calcium sulfate and sodium chloride during glacial maximums ; on the other hand, primary components were sodium sulfate during interglacials.
    Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 21710002
  • Physical mechanisms for formation of strata at the surface of the ice sheet in the interior of the Antarctic ice sheet, and remote sensing for them with radio waves
    Grants-in-Aid for Scientific Research
    2008 - 2010
    FUJITA Shuji; FUKUI Kotaro; KAWAMURA Kenji; AZUMA Kumiko; SURDYK Sylviane; ENOMOTO Horoyuki; NAKAZAWA Fumio; SUGIYAMA Shin; MIYAMOTO Atsushi; IIZUKA Yoshinori; HORI Akira; NISHIMURA Daisuke
    Using the snow/firn samples and data obtained by traversing the interior of the Antarctic ice sheet, we studied physical mechanisms of the formation of the strata within snow and firn. Major findings include spatial distribution of the depositional environment in Antarctica, seasonal effects on firn density and spatial distribution of the subglacial environment. In addition, we found that polarization ratio of the microwave emissivity from the ice sheet surface is well correlated to accumulation rate observed by radar sounding.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), National Institute of Polar Research, 20241007
  • Reconstruct of depositions of terrestrial materials into the northern North Pacific by ice-core analysis
    Grants-in-Aid for Scientific Research
    2007 - 2009
    SHIRAIWA Takayuki; MATOBA Sumito; YAMATAGA Kotaro; SUGIYAMA Shin; IIZUKA Yoshinori; YOSHIKAWA Kenji; SASAKI Hirotaka; FUKUDA Takehiro; TSUSHIMA Akane
    In order to study the relationship between the North Pacific climate regime shift and ocean primary production, we analyzed iron concentrations in an ice core drilled at Aurora Peak, Alaskan Range. It was found that the averaged iron deposition was 8.8mg m^2yr^<-1> for the last 10 years, but it was 29 and 19mg m^2yr^<-1> for 2001 and 2002 when there were significant Kosa events. The results suggest that the atmospheric iron deposition to the upper 30-m mixed layer will not affect the biomass production in average but the amounts as recorded in 2001 and 2002 will be high enough to affect the ocean primary production.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Research Institute for Humanity and Nature, 19340137
  • Paleoclimatic reconstruction on inter-annual scale of interglacials analyzed by Dome Fuji ice core, Antractica
    Grants-in-Aid for Scientific Research(若手研究(B))
    2007 - 2008
    Yoshinori IIZUKA
    南極ドームふじ氷床コアの溶存イオン濃度を数mm 分解能の深さ分解能で分析し、おもな溶存イオン濃度の短周期変動が季節変動に起因していることを示唆した。完新世のナトリウムイオン濃度の短周期変動が南極海の海氷面積の季節変動と対応していることを提唱し、南極のヒプシサーマルの時期はそれ以後のやや寒冷な時期に比べて、海氷の季節変動幅が小さく、冬季に現在ほど北上していない可能性を示唆した。
    Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 19710001
  • Study on abrupt climate and environment changes during glacial cycles by high time resolution anlalyzes of polar ice cores.
    Grants-in-Aid for Scientific Research(基盤研究(S))
    2003 - 2007
    Yoshiyuki FUJII; 神山 孝吉; 吉田 尚弘; 古川 晶雄; 藤田 秀二; 本山 秀明; 東 久美子; 三宅 隆之; 青木 周司; 吉田 尚弘; 飯塚 芳徳; 川村 賢二
    (Objects) The two deep ice cores from Dome Fuji, Antarctica showed the occurrences of a number of abrupt climate and environment changes during the glacial cycles. Objectives of the research project are 1. to establish high time resolution analysis of the deep ice core from Dome Fuji, 2. to reconstruct detailed climatic and environment changes with yearly time scale, and 3. to study scenarios caused the abrupt changes in climate and environment(Results) The high time resolution analyses of ice core in various climate stages (Holocene, LGM, interstadial and glacial stages) were done and the ...
    Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(S), 国立極地研究所, Coinvestigator not use grants, Competitive research funding, 15101001
  • 氷床コア中無機イオン濃度の高時間分解能解析による完新世・最終氷期の季節変動解読
    科学研究費補助金(若手研究(B))
    2004 - 2006
    飯塚 芳徳
    フィルンのイオン濃度プロファイルをこれまでにない高い時間分解能で測定した。その結果、主要なイオン種間の反応が表面から約8mの範囲(反応層)で生じていることを明らかにした。例えば、硫酸塩について、表面積雪の[Na^+]+[Mg^<2+>]のプロファイルと[SO_4^<2->]プロファイルの相関を調べると、部分的な相関は認められるが相関係数としては0.6程度であるのに対して、深度8mで0.8を越えて両者のプロファイルは酷似するようになる。すなわち、大気中でも硫酸塩は形成されるが、フィルン内部でもNaCl、MgCl_2(固)とH_2SO_4(液)の反応によって、硫酸塩が生成されることを意味している。また、この反応は、液体であるH_2SO_4が氷粒子の表面に広がって固体粒子であるNaCl等と接触することによって生ずると考えられるから、反応層以深のSO_4^<2->の濃度プロファイルは各深度の[Na^+]+[Mg^<2+>]プロファイルをなぞっているに他ならない。この例のように、生成される塩微粒子や液相で残る酸等の量や分布には、その深度のコアに含まれるイオン濃度のバランスによって様々な違いが生ずるが、[Na^+]や[Mg^<2+>]などのカチオンは堆積後移動しにくいため良い古気候シグナルになることがわかった。現在、カチオンを用いて季節変動による化学物質の存在状態の違いから完新世・最終氷...
    文部科学省, 若手研究(B), 弓削商船高等専門学校->北海道大学, Principal investigator, Competitive research funding, 16710012
  • Physical processes in polar ice sheets and high resolution analyses of Earth's history in climatic and environmental changes
    Grants-in-Aid for Scientific Research(学術創成研究費)
    2002 - 2006
    Takeo HONDOH; 成田 英器; 白岩 孝行; 堀 彰; 藤田 秀二; 飯塚 芳徳; GREVE R・G; 亀田 貴雄
    The aim of the present study is to develop a new research field, Nanoglaciology, for better understanding the ice sheet processes on a macroscopic scale on the basis of various microphysical mechanisms involved in the processes, and to clarify the meaning of paleoclimate-and paleoenvironment-signals and their reliabilities. The main results obtained are summarized as ;1. A mass transfer in the firn and the formation process of layer structures : We revealed structural changes of the layering formed at the surface with depth by the use of various experimental methods. Using SEM-EDS and micro...
    Ministry of Education, Culture, Sports, Science and Technology, 学術創成研究費, 北海道大学, Coinvestigator not use grants, Competitive research funding, 14GS0202