Updated on 2023/09/19

写真a

 
MIYAKE Fusa
 
Organization
Institute for Space-Earth Environmental Research Division for Cosmic Ray Research Associate professor
Graduate School
Graduate School of Science
Title
Associate professor
Contact information
メールアドレス
External link

Degree 1

  1. 博士(理学) ( 2013.12   名古屋大学 ) 

Research Interests 2

  1. 宇宙線生成核種

  2. 太陽活動

Research Areas 1

  1. Natural Science / Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics

Current Research Project and SDGs 1

  1. 宇宙線生成核種を用いた過去の極端太陽現象の調査

Research History 3

  1. Nagoya University   Institute for Space-Earth Environmental Research Division for Cosmic Ray Research   Associate professor

    2017.4

  2. アリゾナ大学滞在研究員

    2015.1 - 2016.3

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    Country:United States

  3. Institute for Advanced Research (Institute for Space-Earth Environmental Research), Nagoya University   Designated assistant professor

    2014.4 - 2017.3

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    Country:Japan

Education 2

  1. Nagoya University   Graduate School, Division of Natural Science

    - 2013.12

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    Country: Japan

  2. Nagoya University   Faculty of Science

    - 2009.3

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    Country: Japan

Professional Memberships 3

  1. 日本物理学会

  2. 日本地球惑星科学連合

  3. 応用物理学会

Awards 4

  1. José A. Boninsegna Frontiers in Dendrochronology Award

    2022.6   Tree-Ring Society  

    Fusa Miyake

  2. 平成29年度 文部科学大臣表彰 若手科学者賞

    2017.4   文部科学省  

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    Country:Japan

  3. 育志賞

    2014   日本学術振興会  

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    Country:Japan

  4. 名古屋大学学術奨励賞

    2013   名古屋大学  

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    Country:Japan

 

Papers 48

  1. Another rapid event in the carbon-14 content of tree rings Reviewed

    F. Miyake, K. Masuda, T. Nakamura

    Nature Communications     2013

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/ncomms2873

  2. A signature of cosmic-ray increase in AD 774-775 from tree rings in Japan Reviewed

    F. Miyake, K. Nagaya, K. Masuda, T. Nakamura

    Nature     page: 240-242   2012

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

  3. TWO NEW MILLENNIUM-LONG TREE-RING OXYGEN ISOTOPE CHRONOLOGIES (2349–1009 BCE AND 1412–466 BCE) FROM JAPAN

    Masaki Sano, Katsuhiko Kimura, Fusa Miyake, Fuyuki Tokanai, Takeshi Nakatsuka

    Radiocarbon   Vol. 65 ( 3 ) page: 721 - 732   2023.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Cambridge University Press (CUP)  

    ABSTRACT

    We present two new millennium-long tree-ring oxygen isotope chronologies for central and northern Japan, based on 9693 annually resolved measurements of tree-ring oxygen isotopes from 39 unearthed samples consisting mainly of Japanese cedar (Cryptomeria japonica). These chronologies were developed through cross-dating of tree-ring widths and δ<sup>18</sup>O data from multiple samples covering the periods 2349–1009 BCE (1341 yr) and 1412–466 BCE (947 yr) for central and northern Japan, respectively. In combination with our published chronology for central Japan, the tree-ring δ<sup>18</sup>O dataset currently available covers the past 4354 yr (2349 BCE to 2005 CE), which represents the longest annually resolved tree-ring δ<sup>18</sup>O dataset for Asia. Furthermore, the high-resolution temporal record of <sup>14</sup>C contents independently developed by Sakurai et al. (2020) was reproduced by our <sup>14</sup>C measurements of earlywood and latewood in annual rings for the period 667–660 BCE.

    DOI: 10.1017/RDC.2023.29

    Web of Science

    Scopus

  4. Present status of the YU-AMS system and its operation over the past 10 years Reviewed

    Mirei Takeyama, Toru Moriya, Hisako Saitoh, Hiroko Miyahara, Fusa Miyake, Motonari Ohyama, Rimi Sato, Rie Shitara, Hirohisa Sakurai, Fuyuki Tokanai

    Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms   Vol. 538   page: 30 - 35   2023.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.nimb.2023.01.021

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  5. A WIGGLE-MATCHED 297-YR TREE-RING OXYGEN ISOTOPE RECORD FROM THAILAND: INVESTIGATING THE <sup>14</sup>C OFFSET INDUCED BY AIR MASS TRANSPORT FROM THE INDIAN OCEAN

    Masaki Sano, Nathsuda Pumijumnong, Koji Fujita, Masataka Hakozaki, Fusa Miyake, Takeshi Nakatsuka

    Radiocarbon   Vol. 65 ( 2 ) page: 505 - 519   2023.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Cambridge University Press (CUP)  

    ABSTRACT

    Regional offsets from Northern Hemisphere radiocarbon (<sup>14</sup>C) calibration curves are widely recognized for monsoon Asia and often hinder accurate <sup>14</sup>C dating. In this paper, we explore the possible linkage between summer monsoon intensity and <sup>14</sup>C offsets using tree-ring δ<sup>18</sup>O and <sup>14</sup>C data from Thailand. We developed a 297-yr floating tree-ring δ<sup>18</sup>O chronology comprising seven teak log-coffin samples from the Ban Rai rock shelter site, northwestern Thailand. The outermost ring of our chronology was estimated to date from 358–383 CE, within a 95.4% (2σ) probability range, based on a total of 10 <sup>14</sup>C measurements that were wiggle-matched against a mixed calibration curve evenly weighted from the IntCal20 and SHCal20 curves. Backward trajectory analysis showed that an intensified (weakened) summer monsoon detected in a modern tree-ring δ<sup>18</sup>O chronology was most likely to be induced by increased (decreased) air mass transport from the tropical Indian Ocean, which is an area of intense upwelling where the <sup>14</sup>C concentration is lower than the atmospheric <sup>14</sup>C level. However, partly because of the limited sample size and dating uncertainty, the direct linkage between the tree-ring δ<sup>18</sup>O series and <sup>14</sup>C records obtained from our teak log-coffin samples could not be statistically verified.

    DOI: 10.1017/RDC.2023.14

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  6. Modeling the Transport and Deposition of <sup>10</sup> Be Produced by the Strongest Solar Proton Event During the Holocene Reviewed

    T. C. Spiegl, S. Yoden, U. Langematz, T. Sato, R. Chhin, S. Noda, F. Miyake, K. Kusano, K. Schaar, M. Kunze

    Journal of Geophysical Research: Atmospheres   Vol. 127 ( 13 )   2022.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union (AGU)  

    Prominent excursions in the number of cosmogenic nuclides (e.g., 10Be) around 774 CE/775 document the most severe solar proton event (SPE) throughout the Holocene. Its manifestation in ice cores is valuable for geochronology, but also for solar-terrestrial physics and climate modeling. Using the ECHAM/MESSy Atmospheric Chemistry (EMAC) climate model in combination with the Warning System for Aviation Exposure to SEP (WASAVIES), we investigate the transport, mixing, and deposition of the cosmogenic nuclide 10Be produced by the 774 CE/775 SPE. By comparing the model results to the reconstructed 10Be time series from four ice core records, we study the atmospheric pathways of 10Be from its stratospheric source to its sink at Earth's surface. The reconstructed post-SPE evolution of the 10Be surface fluxes at the ice core sites is well captured by the model. The downward transport of the 10Be atoms is controlled by the Brewer-Dobson circulation in the stratosphere and cross-tropopause transport via tropopause folds or large-scale sinking. Clear hemispheric differences in the transport and deposition processes are identified. In both polar regions the 10Be surface fluxes peak in summertime, with a larger influence of wet deposition on the seasonal 10Be surface flux in Greenland than in Antarctica. Differences in the peak 10Be surface flux following the 774 CE/775 SPE at the drilling sites are explained by specific meteorological conditions depending on the geographic locations of the sites.

    DOI: 10.1029/2021JD035658

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2021JD035658

  7. Regional Differences in Carbon-14 Data of the 993 CE Cosmic Ray Event Reviewed

    Fusa Miyake, Masataka Hakozaki, Katsuhiko Kimura, Fuyuki Tokanai, Toshio Nakamura, Mirei Takeyama, Toru Moriya

    Frontiers in Astronomy and Space Sciences   Vol. 9   2022.7

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Frontiers Media SA  

    Cosmogenic nuclides such as <sup>14</sup>C from tree rings and <sup>10</sup>Be and <sup>36</sup>Cl from ice cores are excellent proxies for the past extremely large solar energetic particle (SEP) events, which are dozens of times larger than the largest SEP event in the history of observation. So far, several rapid <sup>14</sup>C increases have been discovered, which are considered to have originated from extreme SEP events (or set of successive SEP events) from verifications using multiple cosmogenic nuclide analyses in natural archives. Although these events are characterized by a rapid increase in cosmogenic nuclide concentrations, <sup>14</sup>C data recorded worldwide do not always show similar variations, especially during the 993 CE event, where a rapid increase was recorded in either 992–993 CE or 993–994 CE in several records. We present new <sup>14</sup>C data of the Japanese cedar sample for the 993 CE event. Although the latest data show no significant increase in 1 year, an overall increase pattern is consistent with the previously reported <sup>14</sup>C data of the Japanese cedar, which supports that a significant <sup>14</sup>C increase occurred from 993 to 994 CE in the Japanese sample. Given the dominant <sup>14</sup>C production in high latitudes by SEPs, the difference in timing of increase may be a transport effect in the atmosphere. Moreover, the difference in the timing of the <sup>14</sup>C increase can cause a 1-year age-determination error using the 993 CE radiocarbon spike. Compared with the <sup>14</sup>C data between tree samples from high latitude and midlatitude, including Japan, high-latitude data can capture <sup>14</sup>C changes originating from SEP events more quickly and clearly and may be more suitable for a SEP event exploration in the past.

    DOI: 10.3389/fspas.2022.886140

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  8. High‐Resolution 10 Be and 36 Cl Data from the Antarctic Dome Fuji Ice Core (∼100 years around 5480 BCE): An Unusual Grand Solar Minimum Occurrence? Reviewed

    K. Kanzawa, F. Miyake, K. Horiuchi, K. Sasa, K. Takano, M. Matsumura, T. Takahashi, Y. Motizuki, K. Takahashi, Y. Nakai, K. Ohtani, Y. Tada, Y. Ochiai, H. Motoyama, H. Matsuzaki, A. Yamazaki, Y. Muramatsu, T. Yamagata

    Journal of Geophysical Research: Space Physics   Vol. 126 ( 10 )   2021.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union (AGU)  

    Cosmogenic nuclides in tree rings and polar ice cores record the information of past cosmic ray intensities and solar activities. A large 14C increase over 10 years has been discovered around 5480 BCE. The 14C variations in this event differ from those of other short-term cosmic ray events and typical grand solar minima. To elucidate the cause of the 14C increase around 5480 BCE, we measured the 10Be and 36Cl concentrations in the Antarctic Dome Fuji ice core at quasi-annual and 4–5 years resolutions, respectively. Based on the combined 14C, 10Be, and 36Cl data, the 5480 BCE event was probably not caused by a solar proton event (SPE) or a gamma-ray event, because the 36Cl concentration did not significantly increase as expected in these events. The incremented 10Be data were enhanced similarly to those of recent grand solar minima, but more rapidly increased (over ∼10 years). These results suggest that an unusual grand solar minimum occurred around 5480 BCE, characterized by a rapidly decreasing solar activity.

    DOI: 10.1029/2021JA029378

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  9. The measurement of ion-induced cloud nucleation irradiated with a 180-MeV nitrogen ion and proton beams at HIMAC accelerator facility

    Suzuki A., Itow Y., Sako T., Nakayama T., Masuda K., Miyake F., Matsumi Y., Miura K., Kusano K.

    Proceedings of Science   Vol. 358   2021.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Proceedings of Science  

    Ion-induced nucleation by cosmic rays influenced by solar modulation is of interest, and several studies with radioactive sources or accelerator beams have been performed. We focused on ionization with high-linear energy transfer (LET) particles, such as protons, neutrons, and ions, in secondary cosmic rays and the ion density of the secondary cosmic rays near the ground using the excel-based program for calculating atmospheric cosmic-ray spectrum (EXPACS). According to the calculation, not only muons but also protons and neutrons leave substantial traces of solar modulation at an altitude of 3 km from the ground. To verify the ion-induced nucleation by these secondary high-LET cosmic rays, a chamber experiment was conducted at the accelerator facility HIMAC. Using a chamber with a capacity of 75 L, experiments were conducted by irradiating protons and nitrogen ion beams with a constant energy of 180 MeV/u with varying intensity. The experimental results confirm that the ion density and aerosol density increased as the beam intensity increased. The aerosol density was found to be proportional to the ion density, but irrelevant to the ionization density. It was concluded that the ion-induced nucleation by high-LET secondary cosmic rays, such as protons and neutrons, provides no evidence of enhancement owing to ionization density and cannot account for the claimed variation of cloud formation due to the solar modulation.

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  10. Cosmogenic Evidence for Past SEP Events

    Miyake F.

    Proceedings of Science   Vol. 358   2021.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Proceedings of Science  

    Terrestrial cosmogenic nuclides (e.g., 14C, 10Be, and 36Cl) are primarily produced by galactic cosmic rays. However, a certain amount of these nuclides is also produced by solar energetic particles (SEPs) derived from sporadic solar events such as solar flares and coronal mass ejections. Cosmic ray increase events in AD 774/775, AD 993/994 (or AD 992/993), and ~BC 660 have been discovered using 14C data in tree rings (Miyake et al. 2012, 2013; Park et al. 2017). It is considered that the most plausible cause of these events was an extreme SEP events with very hard energy spectra based on 14C analyses of tree rings and 10Be and 36Cl analyses of ice cores (e.g., Mekhaldi et al. 2015; Miyake et al. 2015, 2019; Büntgen et al. 2018; O'Hare et al. 2019). These SEP events are estimated to be several dozens of times larger than the largest events seen in direct observations, and an event of that size might have a serious impact on modern society. Therefore, it is important to investigate the occurrence rate of past extreme events. In recent years, surveys of past SEP events have been actively conducted via cosmogenic nuclide measurements with high time resolution (~one-year resolution). Here the detected past SEP candidates and a further survey of similar events are reviewed.

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  11. A Single-Year Cosmic Ray Event at 5410 BCE Registered in 14C of Tree Rings. Reviewed International coauthorship International journal

    F Miyake, I P Panyushkina, A J T Jull, F Adolphi, N Brehm, S Helama, K Kanzawa, T Moriya, R Muscheler, K Nicolussi, M Oinonen, M Salzer, M Takeyama, F Tokanai, L Wacker

    Geophysical research letters   Vol. 48 ( 11 ) page: e2021GL093419   2021.6

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    The annual 14C data in tree rings is an outstanding proxy for uncovering extreme solar energetic particle (SEP) events in the past. Signatures of extreme SEP events have been reported in 774/775 CE, 992/993 CE, and ∼660 BCE. Here, we report another rapid increase of 14C concentration in tree rings from California, Switzerland, and Finland around 5410 BCE. These 14C data series show a significant increase of ∼6‰ in 5411-5410 BCE. The signature of 14C variation is very similar to the confirmed three SEP events and points to an extreme short-term flux of cosmic ray radiation into the atmosphere. The rapid 14C increase in 5411/5410 BCE rings occurred during a period of high solar activity and 60 years after a grand 14C excursion during 5481-5471 BCE. The similarity of our 14C data to previous events suggests that the origin of the 5410 BCE event is an extreme SEP event.

    DOI: 10.1029/2021GL093419

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  12. Exploration of Carrington SEP(Solar Energetic Particle) Event with radiocarbon in tree-ring

    Tada Yuma, Miyake Fusa, Kanzawa Kayo, Nakamura Toshio, Nakatuka Takeshi, Tokanai Fuyuki, Sakamoto Minoru, Hakozaki Makoto

    JSAP Annual Meetings Extended Abstracts   Vol. 2020.2   page: 356 - 356   2020.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:The Japan Society of Applied Physics  

    DOI: 10.11470/jsapmeeting.2020.2.0_356

  13. Findings from an in-Depth Annual Tree-Ring Radiocarbon Intercomparison Reviewed International coauthorship International journal

    L. Wacker, E. M. Scott, A. Bayliss, D. Brown, E. Bard, S. Bollhalder, M. Friedrich, M. Capano, A. Cherkinsky, D. Chivall, B. J. Culleton, M. W. Dee, R. Friedrich, G. W.L. Hodgins, A. Hogg, D. J. Kennett, T. D.J. Knowles, M. Kuitems, T. E. Lange, F. Miyake, M. J. Nadeau, T. Nakamura, J. P. Naysmith, J. Olsen, T. Omori, F. Petchey, B. Philippsen, C. Bronk Ramsey, G. V.Ravi Prasad, M. Seiler, J. Southon, R. Staff, T. Tuna

    Radiocarbon   Vol. 62 ( 4 ) page: 873 - 882   2020.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    © 2020 Cambridge University Press. All rights reserved. The radiocarbon (C) calibration curve so far contains annually resolved data only for a short period of time. With accelerator mass spectrometry (AMS) matching the precision of decay counting, it is now possible to efficiently produce large datasets of annual resolution for calibration purposes using small amounts of wood. The radiocarbon intercomparison on single-year tree-ring samples presented here is the first to investigate specifically possible offsets between AMS laboratories at high precision. The results show that AMS laboratories are capable of measuring samples of Holocene age with an accuracy and precision that is comparable or even goes beyond what is possible with decay counting, even though they require a thousand times less wood. It also shows that not all AMS laboratories always produce results that are consistent with their stated uncertainties. The long-term benefits of studies of this kind are more accurate radiocarbon measurements with, in the future, better quantified uncertainties.

    DOI: 10.1017/RDC.2020.49

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  14. THE INTCAL20 NORTHERN HEMISPHERE RADIOCARBON AGE CALIBRATION CURVE (0-55 CAL KBP) Reviewed International coauthorship International journal

    Paula J. Reimer, William E. N. Austin, Edouard Bard, Alex Bayliss, Paul G. Blackwell, Christopher Bronk Ramsey, Martin Butzin, Hai Cheng, R. Lawrence Edwards, Michael Friedrich, Pieter M. Grootes, Thomas P. Guilderson, Irka Hajdas, Timothy J. Heaton, Alan G. Hogg, Konrad A. Hughen, Bernd Kromer, Sturt W. Manning, Raimund Muscheler, Jonathan G. Palmer, Charlotte Pearson, Johannes van der Plicht, Ron W. Reimer, David A. Richards, E. Marian Scott, John R. Southon, Christian S. M. Turney, Lukas Wacker, Florian Adolphi, Ulf Buentgen, Manuela Capano, Simon M. Fahrni, Alexandra Fogtmann-Schulz, Ronny Friedrich, Peter Koehler, Sabrina Kudsk, Fusa Miyake, Jesper Olsen, Frederick Reinig, Minoru Sakamoto, Adam Sookdeo, Sahra Talamo

    RADIOCARBON   Vol. 62 ( 4 ) page: 725 - 757   2020.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:UNIV ARIZONA DEPT GEOSCIENCES  

    Radiocarbon (C-14) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric C-14 concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international C-14 calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable C-14 offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the C-14 ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine C-14 data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.

    DOI: 10.1017/RDC.2020.41

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  15. 775 and 994 14C events in the tree-rings of northern Japanese trees International journal

    M. Hakozaki, F. Miyake, T. Nakamura

    Proceedings of EA-AMS 8 & JAMS-22     page: 89 - 90   2020.6

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    Language:English   Publishing type:Research paper (international conference proceedings)  

  16. Prolonged production of 14C during the ~660 BCE solar proton event from Japanese tree rings. Reviewed International journal

    Hirohisa Sakurai, Fuyuki Tokanai, Fusa Miyake, Kazuho Horiuchi, Kimiaki Masuda, Hiroko Miyahara, Motonari Ohyama, Minoru Sakamoto, Takumi Mitsutani, Toru Moriya

    Scientific reports   Vol. 10 ( 1 ) page: 660 - 660   2020.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

    Annual rings record the intensity of cosmic rays (CRs) that had entered into the Earth's atmosphere. Several rapid 14C increases in the past, such as the 775 CE and 994CE 14C spikes, have been reported to originate from extreme solar proton events (SPEs). Another rapid 14C increase, also known as the ca. 660 BCE event in German oak tree rings as well as increases of 10Be and 36Cl in ice cores, was presumed similar to the 775 CE event; however, as the 14C increase of approximately 10‰ in 660 BCE had taken a rather longer rise time of 3-4 years as compared to that of the 775 CE event, the occurrence could not be simply associated to an extreme SPE. In this study, to elucidate the rapid increase in 14C concentrations in tree rings around 660 BCE, we have precisely measured the 14C concentrations of earlywoods and latewoods inside the annual rings of Japanese cedar for the period 669-633 BCE. Based on the feature of 14C production rate calculated from the fine measured profile of the 14C concentrations, we found that the 14C rapid increase occurred within 665-663.5 BCE, and that duration of 14C production describing the event is distributed from one month to 41 months. The possibility of occurrence of consecutive SPEs over up to three years is offered.

    DOI: 10.1038/s41598-019-57273-2

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  17. Characterization of the Measured Events International journal

    Cliver E, Ebihara Y, Hayakawa H, Jull T, Mekhaldi F, Miyake F, Muscheler R

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach6

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  18. Measurements of Radionuclides International journal

    Wacker L, Baroni M, Mekhaldi F, Miyake F, Oinonen M

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach5

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  19. Further Search for Extreme Events International journal

    Miyake F, Ebihara Y, Hayakawa H, Maehara H, Mitsuma Y, Usoskin I, Wang F, Willis D. M

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach7

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  20. Extreme Solar Particle Storms The hostile Sun Introduction International journal

    Usoskin I, Miyake F

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach1

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  21. 古木から読み解く過去の宇宙

    三宅 芙沙

    日本歴史   Vol. 870号(11月号)   page: 74 - 75   2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    CiNii Research

  22. Radiocarbon Production Events and their Potential Relationship with the Schwabe Cycle Reviewed International journal

    A. Scifo, M. Kuitems, A. Neocleous, B. J. S. Pope, D. Miles, E. Jansma, P. Doeve, A. M. Smith, F. Miyake, M. W. Dee

    Scientific Reports   Vol. 9 ( 1 ) page: 17056   2019.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    Extreme cosmic radiation events occurred in the years 774/5 and 993/4 CE, as revealed by anomalies in the concentration of radiocarbon in known-age tree-rings. Most hypotheses point towards intense solar storms as the cause for these events, although little direct experimental support for this claim has thus far come to light. In this study, we perform very high-precision accelerator mass spectrometry (AMS) measurements on dendrochronological tree-rings spanning the years of the events of interest, as well as the Carrington Event of 1859 CE, which is recognized as an extreme solar storm even though it did not generate an anomalous radiocarbon signature. Our data, comprising 169 new and previously published measurements, appear to delineate the modulation of radiocarbon production due to the Schwabe (11-year) solar cycle. Moreover, they suggest that all three events occurred around the maximum of the solar cycle, adding experimental support for a common solar origin.

    DOI: 10.1038/s41598-019-53296-x

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  23. The Earliest Candidates of Auroral Observations in Assyrian Astrological Reports: Insights on Solar Activity around 660 BCE Reviewed International journal

    H. Hayakawa, Y. Mitsuma, Y. Ebihara, F. Miyake

    Astrophys. J. Lett.   Vol. 884 ( 1 )   2019.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    Auroral records found in historical archives and cosmogenic isotopes found in natural archives have served as sound proxies of coronal mass ejections and solar energetic particles (SEPs), respectively, for dates prior to the onset of telescopic sunspot observations in 1610. These space weather events constitute a significant threat to a modern civilization, because of its increasing dependency on an electronic infrastructure. Recent studies have identified multiple extreme space weather events derived from SEPs in natural archives, such as the event in 660 BCE. While the level of solar activity around 660 BCE is of great interest, this had not been within the coverage of the hitherto-known datable auroral records in historical documents that extend back to the 6th century BCE. Therefore, we have examined Assyrian astrological reports in the 8th and 7th centuries BCE, identified three observational reports of candidate aurorae, and dated these reports to approximately 680 BCE-650 BCE. The Assyrian cuneiform tablets let us extend the history of auroral records and solar activity by a century. These cuneiform reports are considered to be the earliest datable records of candidate aurorae and they support the concept of enhanced solar activity suggested by the cosmogenic isotopes from natural archives.

    DOI: 10.3847/2041-8213/ab42e4

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  24. Cosmogenic Evidence for Past SEP Events International journal

    MIYAKE Fusa

    Proc. 36th International Cosmic Ray Conference     2019.8

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    Language:English   Publishing type:Research paper (international conference proceedings)  

  25. 過去3000年間の宇宙線強度年変動 International journal

    三宅芙沙, 増田公明, 中村俊夫, 箱﨑真隆, 木村勝彦, 門叶冬樹, 森谷透, 武山美麗, Jull T, Panyushkina I

    第20回AMSシンポジウム報告集     page: 83 - 86   2019.2

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  26. 10Be signature of the cosmic ray event in the 10th century CE in both hemispheres, as confirmed by quasi‐annual 10Be data from the Antarctic Dome Fuji ice core Reviewed International journal

    F. Miyake, K. Horiuchi, Y. Motizuki, Y. Nakai, K. Takahashi, K. Masuda, H. Motoyama, H. Matsuzaki

    Geophysical Research Letters   Vol. 46 ( 1 ) page: 11 - 18   2019.1

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    DOI: 10.1029/2018GL080475

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  27. Cosmogenic evidence for past SEP events International journal

    Miyake F.

    Proceedings of Science   Vol. 358   2019

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    Terrestrial cosmogenic nuclides (e.g., 14C, 10Be, and 36Cl) are primarily produced by galactic cosmic rays. However, a certain amount of these nuclides is also produced by solar energetic particles (SEPs) derived from sporadic solar events such as solar flares and coronal mass ejections. Cosmic ray increase events in AD 774/775, AD 993/994 (or AD 992/993), and ~BC 660 have been discovered using 14C data in tree rings (Miyake et al. 2012, 2013; Park et al. 2017). It is considered that the most plausible cause of these events was an extreme SEP events with very hard energy spectra based on 14C analyses of tree rings and 10Be and 36Cl analyses of ice cores (e.g., Mekhaldi et al. 2015; Miyake et al. 2015, 2019; Büntgen et al. 2018; O'Hare et al. 2019). These SEP events are estimated to be several dozens of times larger than the largest events seen in direct observations, and an event of that size might have a serious impact on modern society. Therefore, it is important to investigate the occurrence rate of past extreme events. In recent years, surveys of past SEP events have been actively conducted via cosmogenic nuclide measurements with high time resolution (~one-year resolution). Here the detected past SEP candidates and a further survey of similar events are reviewed.

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  28. The measurement of ion-induced cloud nucleation irradiated with a 180-MeV nitrogen ion and proton beams at HIMAC accelerator facility International journal

    Asami Suzuki, Yoshitaka Itow, Takashi Sako, Tomoki Nakayama, Kimiaki Masuda, Fusa Miyake, Yutaka Matsumi, Kazuhiko Miura, Kanya Kusano

    Proceedings of Science   Vol. 358   2019

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    Ion-induced nucleation by cosmic rays influenced by solar modulation is of interest, and several studies with radioactive sources or accelerator beams have been performed. We focused on ionization with high-linear energy transfer (LET) particles, such as protons, neutrons, and ions, in secondary cosmic rays and the ion density of the secondary cosmic rays near the ground using the excel-based program for calculating atmospheric cosmic-ray spectrum (EXPACS). According to the calculation, not only muons but also protons and neutrons leave substantial traces of solar modulation at an altitude of 3 km from the ground. To verify the ion-induced nucleation by these secondary high-LET cosmic rays, a chamber experiment was conducted at the accelerator facility HIMAC. Using a chamber with a capacity of 75 L, experiments were conducted by irradiating protons and nitrogen ion beams with a constant energy of 180 MeV/u with varying intensity. The experimental results confirm that the ion density and aerosol density increased as the beam intensity increased. The aerosol density was found to be proportional to the ion density, but irrelevant to the ionization density. It was concluded that the ion-induced nucleation by high-LET secondary cosmic rays, such as protons and neutrons, provides no evidence of enhancement owing to ionization density and cannot account for the claimed variation of cloud formation due to the solar modulation.

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  29. Author Correction: Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE. Reviewed International journal

    Büntgen U, Wacker L, Galván JD, Arnold S, Arseneault D, Baillie M, Beer J, Bernabei M, Bleicher N, Boswijk G, Bräuning A, Carrer M, Ljungqvist FC, Cherubini P, Christl M, Christie DA, Clark PW, Cook ER, D'Arrigo R, Davi N, Eggertsson Ó, Esper J, Fowler AM, Gedalof Z, Gennaretti F, Grießinger J, Grissino-Mayer H, Grudd H, Gunnarson BE, Hantemirov R, Herzig F, Hessl A, Heussner KU, Jull AJT, Kukarskih V, Kirdyanov A, Kolář T, Krusic PJ, Kyncl T, Lara A, LeQuesne C, Linderholm HW, Loader NJ, Luckman B, Miyake F, Myglan VS, Nicolussi K, Oppenheimer C, Palmer J, Panyushkina I, Pederson N, Rybníček M, Schweingruber FH, Seim A, Sigl M, Churakova Sidorova O, Speer JH, Synal HA, Tegel W, Treydte K, Villalba R, Wiles G, Wilson R, Winship LJ, Wunder J, Yang B, Young GHF

    Nature communications   Vol. 9 ( 1 ) page: 5399   2018.12

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    DOI: 10.1038/s41467-018-07636-6

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  30. Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE Reviewed International journal

    Buntgen Ulf, Wacker Lukas, Galvan J. Diego, Arnold Stephanie, Arseneault Dominique, Baillie Michael, Beer Jurg, Bernabei Mauro, Bleicher Niels, Boswijk Gretel, Brauning Achim, Carrer Marco, Ljungqvist Fredrik Charpentier, Cherubini Paolo, Christl Marcus, Christie Duncan A, Clark Peter W, Cook Edward R, D'Arrigo Rosanne, Davi Nicole, Eggertsson Olafur, Esper Jan, Fowler Anthony M, Gedalof Ze'ev, Gennaretti Fabio, Griessinger Jussi, Grissino-Mayer Henri, Grudd Hakan, Gunnarson Bjorn E, Hantemirov Rashit, Herzig Franz, Hessl Amy, Heussner Karl-Uwe, Jull A. J. Timothy, Kukarskih Vladimir, Kirdyanov Alexander, Kolar Tomas, Krusic Paul J, Kyncl Tomas, Lara Antonio, LeQuesne Carlos, Linderholm Hans W, Loader Neil J, Luckman Brian, Miyake Fusa, Myglan Vladimir S, Nicolussi Kurt, Oppenheimer Clive, Palmer Jonathan, Panyushkina Irina, Pederson Neil, Rybnicek Michal, Schweingruber Fritz H, Seim Andrea, Sigl Michael, Churakova (Sidorova, Olga, Speer James H, Synal Hans-Arno, Tegel Willy, Treydte Kerstin, Villalba Ricardo, Wiles Greg, Wilson Rob, Winship Lawrence J, Wunder Jan, Yang Bao, Young Giles H. F

    NATURE COMMUNICATIONS   Vol. 9 ( 1 ) page: 3605   2018.9

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    Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the C-14 content in 484 individual tree rings formed in the periods 770-780 and 990-1000 CE. Distinct C-14 excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved C-14 measurements are needed.

    DOI: 10.1038/s41467-018-06036-0

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  31. 14Cスパイク法によるB-Tmテフラの精密年代と相関係数マッチング法の検討 International journal

    奥野充, 八塚槙也, 木村勝彦, 坂本稔, 箱﨑真隆, 洪完, 三宅芙沙, 増田公明, 中村俊夫

    国際火山噴火史情報研究集会講演要旨集2018-1     page: 50 - 54   2018.7

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  32. 日本産樹木年輪の14Cオフセット International journal

    中村俊夫, 増田公明, 三宅芙沙, 箱﨑真隆, 奥野充

    国際火山噴火史情報研究集会講演要旨集2018-1     page: 31 - 41   2018.7

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  33. MORE RAPID C-14 EXCURSIONS IN THE TREE-RING RECORD: A RECORD OF DIFFERENT KIND OF SOLAR ACTIVITY AT ABOUT 800 BC? Reviewed International journal

    Jull A. J. Timothy, Panyushkina Irina, Miyake Fusa, Masuda Kimiaki, Nakamura Toshio, Mitsutani Takumi, Lange Todd E, Cruz Richard J, Baisan Chris, Janovics Robert, Varga Tamas, Molnar Mihaly

    RADIOCARBON   Vol. 60 ( 4 ) page: 1237 - 1248   2018.6

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    Two radiocarbon (C-14) excursions are caused by an increase of incoming cosmic rays on a short time scale found in the Late Holocene (AD 774-775 and AD 993-994), which are widely explained as due to extreme solar proton events (SPE). In addition, a larger event has also been reported at 5480 BC (Miyake et al. 2017a), which is attributed to a special mode of a grand solar minimum, as well as another at 660 BC (Park et al. 2017). Clearly, other events must exist, but could have different causes. In order to detect more such possible events, we have identified periods when the C-14 increase rate is rapid and large in the international radiocarbon calibration (IntCal) data (Reimer et al. 2013). In this paper, we follow on from previous studies and identify a possible excursion starting at 814-813 BC, which may be connected to the beginning of a grand solar minimum associated with the beginning of the Hallstatt period, which is characterized by relatively constant C-14 ages in the period from 800-400 BC. We compare results of annual C-14 measurements from tree rings of sequoia (California) and cedar (Japan), and compare these results to other identified excursions, as well as geomagnetic data. We note that the structure of the increase from 813 BC is similar to the increase at 5480 BC, suggesting a related origin. We also assess whether there are different kinds of events that may be observed and may be consistent with different types of solar phenomena, or other explanations.

    DOI: 10.1017/RDC.2018.53

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  34. Verification of the annual dating of the 10th century Baitoushan volcano eruption based on an 774-775 radiocarbon spike Reviewed International journal

    M. Hakozaki, F. Miyake, T. Nakamura, K. Kimura, K. Masuda, M. Okuno

    Radiocarbon   Vol. 60 ( 1 ) page: 261 - 268   2018.2

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    The so-called Millennium Eruption of Baitoushan Volcano is one of the largest of the Common Era but its date has been uncertain. Recently, Oppenheimer et al. (2017) reported the eruptive year as late AD 946 using a new method called carbon-14 spike matching. However, it is necessary to verify their result to confirm the eruptive year, since only one wood sample was used in their study. We verified the eruptive year by measuring C-14 contents in tree rings from another wood sample buried during the Baitoushan eruption. We succeeded in reproducing the AD 774-775 C-14 spike (Miyake et al. 2012), and counted the number of rings from the outermost ring accompanied by bark to the ring possessing the AD 774-775 C-14 spike. We found the outermost ring was formed in AD 946. Our study supported the result of Oppenheimer et al. (2017), which makes the eruptive year conclusive. Also, we suggest that the C-14 spike-matching method can be a prominent dating tool applicable to ancient woods that are difficult to date using the usual dendrochronology techniques.

    DOI: 10.1017/RDC.2017.75

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  35. Study for elucidation of the 5480 BC cosmic ray event using cosmogenic nuclides 10Be and 36Cl.

    Takano Kenta, Sasa Kimikazu, Takahashi Tsutomu, Matsumura Masumi, Ochiai Yuta, Sueki Keisuke, Miyake Fusa, Horiuchi Kazuho, Matsuzaki Hiroyuki

    Abstracts of Annual Meeting of the Geochemical Society of Japan   Vol. 65 ( 0 ) page: 230   2018

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    <p>Recently, the increase of cosmic ray flux was found around 5480 BC using the <sup>14</sup>C measurements for tree rings with 1- to 2-y resolution. It is assumed that it may be caused by the large solar flares but we cannot specify the detail cause of this event. In this study, we aim to elucidate the cause of 5480 BC cosmic ray event by measuring <sup>10</sup>Be and <sup>36</sup>Cl in the ice core which was drilled at the Dome Fuji Station in Antarctica, and investigate the variation of cosmic ray flux around 5480 BC. The result of <sup>36</sup>Cl concentration variation using the Accelerator Mass Spectrometry (AMS) system in the University of Tsukuba is reported in this presentation. In addition, the performance of <sup>10</sup>Be-AMS and the future plan is also presented.</p>

    DOI: 10.14862/geochemproc.65.0_230

    CiNii Research

  36. 白頭山10世紀噴火のAD775 14C-spikeおよび酸素同位体比年輪年代測定に基づく年代検証 International journal

    箱﨑真隆, 三宅芙沙, 中村俊夫, 木村勝彦, 佐野雅規, 對馬あかね, 李貞, 中塚武, 増田公明, 奥野充

    Korea-Japan dendrochronology workshop toward a new phase of archeology     page: 22 - 22   2017.8

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  37. 樹木年輪と単年宇宙線イベント Invited International journal

    三宅芙沙, 増田公明, 中村俊夫, 箱崎真隆, 木村勝彦, I P Panyushkina・A J, T Ju

    第19回AMSシンポジウム・2016年度「樹木年輪」研究会共同開催シンポジウム報告集     page: 12 - 15   2017.6

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  38. SUPERNOVAE AND SINGLE-YEAR ANOMALIES IN THE ATMOSPHERIC RADIOCARBON RECORD Reviewed International journal

    Michael Dee, Benjamin Pope, Daniel Miles, Sturt Manning, Fusa Miyake

    RADIOCARBON   Vol. 59 ( 2 ) page: 293 - 302   2017.4

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    Single-year spikes in radiocarbon production are caused by intense bursts of radiation from space. Supernovae emit both high-energy particle and electromagnetic radiation, but it is the latter that is most likely to strike the atmosphere all at once and cause a surge in C-14 production. In the 1990s, it was claimed that the supernova in 1006 CE produced exactly this effect. With the C-14 spikes in the years 775 and 994 CE now attributed to extreme solar events, attention has returned to the question of whether historical supernovae are indeed detectable using annual C-14 measurements. Here, we combine new and existing measurements over six documented and putative supernovae, and conclude that no such astrophysical event has yet left a distinct imprint on the past atmospheric C-14 record.

    DOI: 10.1017/RDC.2016.50

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  39. SEARCH FOR ANNUAL C-14 EXCURSIONS IN THE PAST Reviewed International journal

    Fusa Miyake, Kimiaki Masuda, Toshio Nakamura, Katsuhiko Kimura, Masataka Hakozaki, A. J. Timothy Jull, Todd E. Lange, Richard Cruz, Irina P. Panyushkina, Chris Baisan, Matthew W. Salzer

    RADIOCARBON   Vol. 59 ( 2 ) page: 315 - 320   2017.4

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:UNIV ARIZONA DEPT GEOSCIENCES  

    Two radiocarbon excursions (AD 774-775 and AD 993-994) occurred due to an increase of incoming cosmic rays on a short timescale. The most plausible cause of these events is considered to be extreme solar proton events (SPE). It is possible that there are other annual C-14 excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the C-14 contents in bristlecone pine tree-ring samples during the periods when the rate of C-14 increase in the IntCal data is large. We analyzed four periods every other year (2479-2455 BC, 4055-4031 BC, 4465-4441 BC, and 4689-4681 BC), and found no anomalous C-14 excursions during these periods. This study confirms that it is important to do continuous measurements to find annual cosmic-ray events at other locations in the tree-ring record.

    DOI: 10.1017/RDC.2016.54

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  40. Atmospheric impacts of the strongest known solar particle storm of 775 AD Reviewed International journal

    Timofei Sukhodolov, Ilya Usoskin, Eugene Rozanov, Eleanna Asvestari, William T. Ball, Mark A. J. Curran, Hubertus Fischer, Gennady Kovaltsov, Fusa Miyake, Thomas Peter, Christopher Plummer, Werner Schmutz, Mirko Severi, Rita Traversi

    SCIENTIFIC REPORTS   Vol. 7   page: 45257   2017.3

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    Sporadic solar energetic particle (SEP) events affect the Earth's atmosphere and environment, in particular leading to depletion of the protective ozone layer in the Earth's atmosphere, and pose potential technological and even life hazards. The greatest SEP storm known for the last 11 millennia (the Holocene) occurred in 774-775 AD, serving as a likely worst-case scenario being 40-50 times stronger than any directly observed one. Here we present a systematic analysis of the impact such an extreme event can have on the Earth's atmosphere. Using state-of-the-art cosmic ray cascade and chemistry-climate models, we successfully reproduce the observed variability of cosmogenic isotope Be-10, around 775 AD, in four ice cores from Greenland and Antarctica, thereby validating the models in the assessment of this event. We add to prior conclusions that any nitrate deposition signal from SEP events remains too weak to be detected in ice cores by showing that, even for such an extreme solar storm and sub-annual data resolution, the nitrate deposition signal is indistinguishable from the seasonal cycle. We show that such a severe event is able to perturb the polar stratosphere for at least one year, leading to regional changes in the surface temperature during northern hemisphere winters.

    DOI: 10.1038/srep45257

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  41. Large C-14 excursion in 5480 BC indicates an abnormal sun in the mid-Holocene Reviewed International journal

    Fusa Miyake, A. J. Timothy Jull, Irina P. Panyushkina, Lukas Wacker, Matthew Salzer, Christopher H. Baisan, Todd Lange, Richard Cruz, Kimiaki Masuda, Toshio Nakamura

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   Vol. 114 ( 5 ) page: 881 - 884   2017.1

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATL ACAD SCIENCES  

    Radiocarbon content in tree rings can be an excellent proxy of the past incoming cosmic ray intensities to Earth. Although such past cosmic ray variations have been studied by measurements of C-14 contents in tree rings with &gt;= 10-y time resolution for the Holocene, there are few annual C-14 data. There is a little understanding about annual C-14 variations in the past, with the exception of a few periods including the AD 774-775 C-14 excursion where annual measurements have been performed. Here, we report the result of C-14 measurements using the bristlecone pine tree rings for the period from 5490 BC to 5411 BC with 1- to 2-y resolution, and a finding of an extraordinarily large C-14 increase (20 parts per thousand) from 5481 BC to 5471 BC (the 5480 BC event). The C-14 increase rate of this event is much larger than that of the normal grand solar minima. We propose the possible causes of this event are an unknown phase of grand solar minimum, or a combination of successive solar proton events and a normal grand solar minimum.

    DOI: 10.1073/pnas.1613144114

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  42. High-precision age determination of Holocene samples by radiocarbon dating with accelerator mass spectrometry at Nagoya University

    T. Nakamura, K. Masuda, F. Miyake, M. Hakozaki, K. Kimura, H. Nishimoto, E. Hitoki

    Quaternary International     2015

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    DOI: 10.1016/j.quaint.2015.04.014

  43. Cosmic ray event of A.D. 774-775 shown in quasi-annual 10Be data from the Antarctic Dome Fuji ice core

    F. Miyake, A. Suzuki, K. Masuda, K. Horiuchi, H. Motoyama, H. Matsuzaki, Y. Motizuki, K. Takahashi, Y. Nakai

    Geophys. Res. Lett.     2015

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    DOI: 10.1002/2014GL062218

  44. 屋久杉に刻まれた宇宙現象

    三宅芙沙,増田公明

    物理学会誌   Vol. 69 ( 2 ) page: 93-97   2014

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  45. Verification of the cosmic ray event in AD 993-994 by using a Japanese Hinoki tree

    F. Miyake, K. Masuda, M. Hakozaki, T. Nakamura, F. Tokanai, K. Kato, K. Kimura, and T. Mitsutani

    Radiocarbon     2014

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    DOI: 10.2458/56.17769

  46. Radiocarbon ages of annual rings from Japanese wood: Evident age offset based on IntCal09

    T. Nakamura, K. Masuda, F. Miyake, K. Nagaya, T. Yoshimitsu

    Radiocarbon     page: 763-770   2013

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  47. Lengths of Schwabe cycles in the 7th and 8th centuries indicated by precise measurement of carbon-14 content in tree rings

    F. Miyake, K. Masuda, T. Nakamura

    J. Geophys. Res.     2013

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    DOI: 10.1002/2012JA018320

  48. Variation of the Schwabe Cycle Length During the Grand Solar Minimum in the 4th Century BC Deduced from Radiocarbon Content in Tree Rings

    K. Nagaya, K. Kitazawa, F. Miyake, K. Masuda, Y. Muraki, T. Nakamura, H. Miyahara, H. Matsuzaki

    Solar Physics     page: 232-236   2012

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▼display all

Books 1

  1. Extreme Solar Particle Storms: The hostile Sun

    F. Miyake, I. Usoskin, S. Poluianov eds.( Role: Sole author)

    Institute of Physics Publishing  2019.12 

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MISC 18

  1. Investigation of past extreme solar events by radiocarbon analyses

    Miyake Fusa

    Journal of the Atomic Energy Society of Japan   Vol. 65 ( 2 ) page: 104 - 107   2023

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    DOI: 10.3327/jaesjb.65.2_104

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  2. Investigation of Carrington SEP (Solar Energetic Particle) event by using <sup>14</sup>C in tree rings II

    Tada Yuma, Miyake Fusa, Kanzawa Kayo, Nakamura Toshio, Nakatsuka Takeshi, Tokanai Fuyuki, Sakamoto Minoru, Hakozaki Masataka

    JSAP Annual Meetings Extended Abstracts   Vol. 2021.1   page: 477 - 477   2021.2

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    DOI: 10.11470/jsapmeeting.2021.1.0_477

  3. Cosmic ray event at 5410 BCE recorded in carbon-14 data of tree rings

    三宅芙沙, PANYUSHKINA I. P., JULL A.J. T., ADOLPHI F., BREHM N., HELAMA S., 菅澤佳世, 森谷透, MUSCHELER R., NICOLUSSI K., OINONEN M., SALZER M., 武山美麗, 門叶冬樹, WACKER L.

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   Vol. 82nd   2021

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  4. Investigation for the ~5480 BC cosmic ray event by high resolution analysis of <sup>10</sup>Be and <sup>36</sup>Cl from the Antarctic Dome Fuji ice core for ~100 years

    Kanzawa Kayo, Miyake Fusa, Tada Yuma, Horiuchi Kazuho, Ohtani Kou, Sasa Kimikazu, Takahashi Tsutomu, Matsumura Masumi, Ochiai Yuta, Motizuki Yuko, Takahashi Kazuya, Nakai Yoichi, Motoyama Hideaki, Matsuzaki Hiroyuki

    JSAP Annual Meetings Extended Abstracts   Vol. 2020.2   page: 355 - 355   2020.8

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    DOI: 10.11470/jsapmeeting.2020.2.0_355

  5. EUREKA 地球の宇宙線起源同位体に記録された過去の極端太陽イベント—Past Extreme Solar Events Recorded in Cosmogenic Isotopes on Earth

    三宅 芙沙

    天文月報 = The astronomical herald   Vol. 113 ( 4 ) page: 208 - 216   2020.4

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  6. Performance evaluation of originally-developed Automated Graphitization Equipment

    Tada Yuma, Miyake Fusa, Kanzawa Kayo, Kojima Yasusuke, Fujimori Ryuji, Adachi Takumi, Masuda Kimiaki

    JSAP Annual Meetings Extended Abstracts   Vol. 2020.1   page: 595 - 595   2020.2

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    DOI: 10.11470/jsapmeeting.2020.1.0_595

  7. Variations of <sup>10</sup>Be and <sup>36</sup>Cl in the ~5480 BC cosmic ray event: data from the Antarctic Dome Fuji ice core

    Kanzawa Kayo, Miyake Fusa, Tada Yuma, Horiuchi Kazuho, Ohtani Kou, Sasa Kimikazu, Takahashi Tsutomu, Matsumura Masumi, Ochiai Yuta, Motizuki Yuko, Takahashi Kazuya, Nakai Yoichi, Motoyama Hideaki, Mastuzaki Hiroyuki

    JSAP Annual Meetings Extended Abstracts   Vol. 2020.1   page: 602 - 602   2020.2

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    DOI: 10.11470/jsapmeeting.2020.1.0_602

  8. Investigation of cosmic ray events around ~660 BCE using cosmogenic nuclides

    Miyake Fusa, Horiuchi Kazuho, Sakurai Hirohisa, Motizuki Yuko, Nakai Yoichi, Takahashi Kazuya, Motoyama Hideaki, Matsuzaki Hiroyuki

    JSAP Annual Meetings Extended Abstracts   Vol. 2020.1   page: 603 - 603   2020.2

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    DOI: 10.11470/jsapmeeting.2020.1.0_603

  9. 古木から読み解く過去の宇宙

    三宅 芙沙

    日本歴史   Vol. 870号(11月号)   page: 74 - 75   2020

  10. Investigation of past SEP events using cosmogenic nuclides

    Miyake Fusa

    JSAP Annual Meetings Extended Abstracts   Vol. 2019.2   page: 542 - 542   2019.9

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    DOI: 10.11470/jsapmeeting.2019.2.0_542

  11. 低緯度における大気中宇宙線生成核種Be‐7濃度の季節変動と地球規模での大気流跡線解析 International journal

    鈴木颯一郎, 櫻井敬久, 門叶冬樹, 乾恵美子, 三宅芙沙, 増田公明, MITTHUMSIRI Warit, RUFFOLO David, MACATANGAY R

    日本物理学会講演概要集(CD-ROM)   Vol. 74 ( 1 ) page: ROMBUNNO.14aK407‐10 - 466   2019.3

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    Language:Japanese   Publisher:The Physical Society of Japan  

    DOI: 10.11316/jpsgaiyo.74.1.0_466

    J-GLOBAL

  12. Investigation of the origin of the cosmic ray event of BC5480 by measuring <sup>10</sup>Be and <sup>36</sup>Cl concentrations from the Dome Fuji ice core

    Kanzawa Kayo, Miyake Fusa, Horiuchi Kazuho, Sasa Kimikazu, Motizuki Yuko, Takahashi Kazuya, Nakai Yoichi, Motoyama Hideaki, Matsuzaki Hiroyuki

    Meeting Abstracts of the Physical Society of Japan   Vol. 74.2   page: 407 - 407   2019

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    DOI: 10.11316/jpsgaiyo.74.2.0_407

  13. Past cosmic-ray increase events shown in high-precision 14C data

    Miyake Fusa

    JSAP Annual Meetings Extended Abstracts   Vol. 2018.2   page: 54 - 54   2018.9

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    DOI: 10.11470/jsapmeeting.2018.2.0_54

  14. 屋久杉年輪の<sup>14</sup>C濃度測定による12‐14世紀の太陽活動の調査 International journal

    三宅芙沙, 森千尋, 増田公明, 中村俊夫, 木村勝彦, 門叶冬樹

    名古屋大学年代測定研究   Vol. 2   page: 113‐114   2018.3

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    J-GLOBAL

  15. A Proposal <sup>14</sup>C wiggle-matching based on Correlation Coefficient Value: Case study on the B-Tm tephra

    Okuno M., Yatsuzuka S., Kimura K., Sakamoto M., Hakozaki M., Hong W., Miyake F., Masuda K., Nakamura T.

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN   Vol. 2018   page: 230 - 230   2018

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    Language:Japanese   Publisher:The Volcanological Society of Japan  

    DOI: 10.18940/vsj.2018.0_230

  16. Study for elucidation of the 5480 BC cosmic ray event using cosmogenic nuclides 10Be and 36Cl.

    Takano Kenta, Sasa Kimikazu, Takahashi Tsutomu, Matsumura Masumi, Ochiai Yuta, Sueki Keisuke, Miyake Fusa, Horiuchi Kazuho, Matsuzaki Hiroyuki

    Abstracts of Annual Meeting of the Geochemical Society of Japan   Vol. 65 ( 0 ) page: 230   2018

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    Language:Japanese   Publisher:GEOCHEMICAL SOCIETY OF JAPAN  

    Recently, the increase of cosmic ray flux was found around 5480 BC using the <sup>14</sup>C measurements for tree rings with 1- to 2-y resolution. It is assumed that it may be caused by the large solar flares but we cannot specify the detail cause of this event. In this study, we aim to elucidate the cause of 5480 BC cosmic ray event by measuring <sup>10</sup>Be and <sup>36</sup>Cl in the ice core which was drilled at the Dome Fuji Station in Antarctica, and investigate the variation of cosmic ray flux around 5480 BC. The result of <sup>36</sup>Cl concentration variation using the Accelerator Mass Spectrometry (AMS) system in the University of Tsukuba is reported in this presentation. In addition, the performance of <sup>10</sup>Be-AMS and the future plan is also presented.

    DOI: 10.14862/geochemproc.65.0_230

    CiNii Research

  17. 平成28年度名古屋大学総長裁量経費 地域貢献事業「樹木年輪・年縞堆積物から過去の太陽活動,地球の古気候を探る」活動報告 International journal

    南 雅代, 北川淳子, 小島秀彰, 榎並正樹, 加藤丈典, 三宅芙沙, 池田晃子, 窪田 薫, 栗田直幸, 吉田澪代, 椋本ひかり, 藤沢純平, 徳丸 誠, 中村俊夫, 北川浩之

    名古屋大学年代測定研究報告   Vol. 1   page: 170-182   2017.3

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  18. Comparison of 14C Ages from Japanese Tree Ring Samples with IntCal13 and Their Applications

    Nakamura Toshio, Masuda Kimiaki, Miyake Fusa, Hakozaki Masataka

      Vol. 1   page: 108 - 114   2017.3

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    Language:Japanese  

    To investigate the 14C concentration of atmospheric CO2 over the past few millennia in Japan, we measured the 14C age of annual rings from several Japanese trees with calendar dates ranging from ca. 2000 yr old to present, and we compared the tree-ring 14C age with the corresponding 14C age of IntCal13. It was revealed that the 14C age of the annual rings of Japanese trees are not consistent with IntCal13 datasets in some instances. Many cases of 14C age of tree rings are older than those of IntCal13, but younger than those of SHCal13 datasets. The average shift in Nagoya 14C age from IntCal13 datasets and one-sigma errors were obtained to be +26±36, +24±30, +16±22, +5±21, and +14±22 14C yr for the intervals AD72-382, AD589-1072, AD1413-1615, AD1617-1739, and AD1790-1860, respectively. In addition, a wood sample collected from northern end of the mainland of Japan also showed a value of +35±22 14C yr shifted older than IntCal13. We also analyzed 14C age data obtained for trees grown up in Korea, and yielded the values of +17±35 and +6±35 14C yr for the intervals AD1250-1650 and AD 1650-1850, respectively. The Japanese archipelago is situated near the boundary of the inter-tropical convergence zone in summer, and the 14C concentration of atmospheric CO2 over Japan can be influenced by air masses of the Southern Hemisphere with lower 14C concentrations during periods of higher solar activity and heightened East Asian summer monsoons. Korean Peninsula is also influenced by air masses of the Southern Hemisphere. Present results suggest that the southeast end of Eurasian Continent is located in the critical zone from where it is difficult to calibrate the 14C age of tree ring samples using existing calibration datasets. At the moment, it should be noted that calibration of the 14C dates of Japanese samples with IntCal13 induces additional systematic shifts of calibrated ages toward older ages by about 10-30 yr compared with the sample optimum calendar ages.

    DOI: 10.18999/nagubc.1.108

    Other Link: http://hdl.handle.net/2237/00028479

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Presentations 15

  1. A search for past extreme solar events using 14C data in tree rings Invited International conference

    F. Miyake

    Chapmann conference (Chapman on Scientific Challenges Pertaining to Space Weather Forecasting Including Extremes)  2019.2 

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  2. Annual cosmic ray events shown in carbon-14 data from the BC 10th to AD 14th century International conference

    F. Miyake

    23rd Radiocarbon conference  2018.6 

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  3. 樹木年輪の炭素14濃度に刻まれた過去の宇宙線増加現象 Invited

    三宅 芙沙

    第79回応用物理学会 秋季学術講演会  2018.9 

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  4. 樹木年輪から探る過去の大規模SPE Invited

    三宅 芙沙

    SGEPSS  2018.11 

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  5. Rapid cosmic ray events shown in carbon-14 data of tree rings Invited International conference

    F. Miyake

    PSTEP A04 International Workshop  2019.2 

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  6. Cosmogenic Evidences for Past SEP Events Invited International conference

    F. Miyake

    36th International Cosmic Ray Conference, Madison  2019.7 

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  7. Solar bursts recorded in tree rings Invited

    Fusa Miyake

    Forests to Heritage conference  2022.4 

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  8. Toward detections of 14C spikes: regional differences in 14C data

    Fusa Miyake

    24th Radiocarbon  2022.9 

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  9. 宇宙線⽣成核種を⽤いた 過去の極端太陽現象の調査 Invited

    三宅芙沙

    日本質量分析学会同位体比部会2021  2021.11 

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  10. Search for past SEP events using tree-ring 14C data Invited

    Fusa Miyake

    3rd Radiocarbon in the Environment Conference  2021.7 

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  11. Carbon-14 spikes caused by solar energetic particle events Invited

    Fusa Miyake

    AmeriDendro2022  2022.6 

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  12. Extreme solar energetic particle events recorded in cosmogenic nuclides data Invited

    Fusa Miyake

    Space Climate 8  2022.9 

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  13. Extreme solar particle events shown in carbon-14 data

    Fusa Miyake

    AGU fall meeting  2020.12 

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  14. 過去1万年間に生じた大規模な太陽高エネルギー粒子イベント Invited

    第152回 SGEPSS  2022.11.5 

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  15. 過去1万年間の極端太陽高エネルギー粒子イベントの調査 Invited

    2022年度太陽研連シンポジウム  2023.2.22 

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Research Project for Joint Research, Competitive Funding, etc. 1

  1. 宇宙線生成核種による過去数万年の宇宙線大変動探索計画

    2014.9 - 2016

KAKENHI (Grants-in-Aid for Scientific Research) 14

  1. 水月湖年縞堆積物による過去の太陽スーパーフレアの研究

    Grant number:23K17694  2023.6 - 2025.3

    科学研究費助成事業  挑戦的研究(萌芽)

    三宅 芙沙, 中川 毅, 林田 明, 柴田 一成

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    Authorship:Principal investigator 

    Grant amount:\6370000 ( Direct Cost: \4900000 、 Indirect Cost:\1470000 )

    太陽で巨大なフレアが発生すると、その影響が地球へ伝わり、人工衛星故障、通信障害、停電などの被害が発生することが知られている。現代社会の発展、とくに宇宙への進出に伴って、太陽ではどこまで巨大なフレアが発生するのか、世界的な関心が高まりつつある。本研究は、福井県若狭湾沿岸にある水月湖の堆積物中の放射性炭素の分析から、過去の太陽における超巨大フレア(スーパーフレア)の探索を行う。本挑戦的研究が成功すれば、将来的には5万年間の太陽スーパーフレアの歴史や統計的法則、さらには、太陽活動の変遷が判明する道が開かれると期待される。

  2. マルチスケール宇宙線生成核種分析より紐解く地質時代の宇宙・地球現象と環境変動

    Grant number:23H00135  2023.4 - 2027.3

    科学研究費助成事業  基盤研究(A)

    堀内 一穂, 宮原 ひろ子, 三宅 芙沙, 川村 賢二, 大藪 幾美, 山崎 俊嗣, 小田 啓邦, 笹 公和

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    太陽地磁気変動や宇宙線イベントなどに由来する宇宙・地球現象は、地球惑星科学の主要な研究対象の一つであり、近年では災害科学の観点からも注目されている。しかし、地質時代のそれを知る手段は相当に限られる。本研究では、宇宙線と大気との相互作用により生成する宇宙線生成核種を様々な時空間スケールで戦略的に分析することで、過去400万年間の宇宙・地球現象を、連続的もしくは注目する区間で集中的に解明する。またその応用として、アイスコア・堆積物・年輪などの古環境アーカイブから獲得される宇宙線生成核種記録の層序学的利用を推進させるとともに、環境トレーサー・プロキシとしての宇宙線生成核種の利用も開拓する。

  3. Development in the resolution of age calibration of the Yayoi to Kofu periods by high-precision 14C measurements of annual tree rings.

    Grant number:22H00026  2022.4 - 2027.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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  4. Solar activity over the past 10,000 years

    Grant number:20H05643  2020.8 - 2025.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (S)

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\198120000 ( Direct Cost: \152400000 、 Indirect Cost:\45720000 )

  5. 宇宙線生成核種を用いたシュワーベサイクル検出手法の確立

    Grant number:20K20918  2020.7 - 2023.3

    科学研究費助成事業  挑戦的研究(萌芽)

    三宅 芙沙, 堀内 一穂, 箱崎 真隆, 早川 尚志

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    Grant amount:\6370000 ( Direct Cost: \4900000 、 Indirect Cost:\1470000 )

    年輪の14Cや氷床コアの10Beといった宇宙線生成核種は過去の長期的な太陽磁場活動の優れた代替データである。一方、太陽活動を議論する上で大変重要となる太陽11年周期(シュワーベサイクル)は、核種データに現れる振幅が小さいため、宇宙線生成核種を用いた検出手法が未だ確立していない。本研究では、月解像度の年輪14Cデータと、複数地点の氷床コア10Beデータを分析することで、シュワーベサイクル検出法の確立を目指す。本研究が実現することにより、黒点データの妥当性を検証することが可能となるだけでなく、過去数万年間のシュワーベサイクルの調査につながり、太陽物理学をはじめ革新的な影響を及ぼす。
    地球へ降り注ぐ宇宙線量は、太陽磁場活動によって変調を受けているため、年輪の14Cや氷床コアの10Beなどの宇宙線生成核種は過去の長期的な太陽活動の優れた代替データである。一方で、太陽活動を議論する上で重要となる太陽11年周期(シュワーベサイクル)は、核種データに現れる振幅が小さいため、宇宙線生成核種を用いた検出手法が未だ確立していない。本研究では、1年未満の時間分解能の年輪14Cデータと、複数地点の氷床コア10Beデータを分析することで、シュワーベサイクル検出法の確立を目指す。本研究が実現することにより、黒点データの妥当性の検証や過去数万年間のシュワーベサイクルの調査を可能とする。
    2021年度は、信頼のおける黒点データが存在する1800年代について、年輪年代法によって年代が特定されたアラスカ産のシトカスプルースを用いて、14C分析のための準備を行った(試料準備は1844-1876年)。シトカスプルースは針葉樹であり、春先の年輪形成を前年より前に蓄えた炭素を用いて行うと考えられている落葉広葉樹よりもよりリアルタイムの炭素を固定していると考えられる。年輪剥離、セルロース抽出を名古屋大学にて実施し、14C分析はスイスETHにて実施するため(グラファイト抽出、加速器質量分析)、セルロース試料を送付した。また、名古屋大学にて前処理手法の検討などを行い、次年度実施予定の氷床コア中10Be分析のための準備を実施した。
    スイスETHでの14C分析を今年度終える予定であったが、新型コロナウイルスの影響等により分析が完了しなかった。2022年度初め(4-5月)にはデータが得られる予定であることから、課題にやや遅れが生じている。
    2022年度には、現在測定中の試料に加え、1825-1844年の試料も測定し、予定している年代の14Cデータを取得予定である。また、順次氷床コアの10Be分析に着手する。得られた14Cと10Beデータと、黒点データとの比較を行い、シュワーベサイクルがみられるか議論する。

  6. Dendrochronological study for precise chronology of the past 30,000 years of extreme climate and disaster history

    Grant number:20H00035  2020.4 - 2025.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Authorship:Coinvestigator(s)  Grant type:Competitive

  7. 最新型AMS装置の高精度化による単年14Cスパイク年代決定法の研究

    Grant number:20H01369  2020.4 - 2024.3

    科学研究費助成事業  基盤研究(B)

    門叶 冬樹, 宮原 ひろ子, 尾嵜 大真, 白石 哲也, 三宅 芙沙

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    近年、太陽活動や太陽圏環境の変動の他、天体現象にともなうと考えられる突発的な宇宙線増加現象が、14C濃度の異常上昇(14Cスパイク)として過去に度々発生していたことが明らかになりつつある。
    本研究は、最新型のコンパクト加速器質量分析(AMS)システムの高精度化の研究を行い、樹木1年輪毎に対する高精度14C年代AMS測定から、新しい14Cスパイク年代を見出すことで、地域や樹種の差別化なく分解能1年の精度で文化財年代を決定する新しい放射性炭素年代法を創出することである。
    近年、太陽活動や太陽圏環境の変動の他、天体現象にともなうと考えられる突発的な宇宙線増加現象が、14C濃度の異常上昇(14Cスパイク)として過去に度々発生していたことが明らかになりつつある。日本で発見された14Cスパイクを用いた新しい年代測定法を世界に先駆けて確立するために、樹木単年輪中の14C濃度を高精度に分析するための研究開発を開始した。本年度は、山形大学の最新型コンパクトAMSシステム(NEC社製 0.5MV-1.5SDH)を用いて、十分な統計精度と低い系統誤差による14C濃度分析を目標に、以下の開発研究を行った。
    まず、国際原子力機関(IAEA)が提供している標準試料C6(ANU スクロース)とC7(シュウ酸)の14C濃度について、これまでの約10年分のデータを解析し、文献値との比較を行った。その結果、C7については49.53±0.13pMCの結果が得られ、文献値の49.53±0.12pMCと良い一致を示した。一方、C6に対しては150.39±0.29pMCの結果が得られ、文献値の150.61±0.11pMCよりも低い14C濃度の結果となった。C6試料については、Xu等によって我々の測定値よりもさらに低い150.16 ± 0.02という値が報告されており、現在、パレオ・ラボ社とのデータ提供も受けて、IAEA-C6の14C濃度について調べることにした。
    続いて、年輪年代法により年代が付された過去3000年間の試料の中から、樹木単年輪試料を選別し、薄膜状化と化学処理により汚染除去を行った後、塩素漂白、濃アルカリ処理によってα-セルロースを抽出した。抽出したα-セルロース試料を錫ボートに包み、山形大学総合研究所に設置した自動グラファイト作製システムでグラファイト化を行った。そしてグラファイト化した試料をAMSで分析し、14Cスパイクの探査を行った。
    試料中の14C濃度を高精度に分析するための研究開発は、順調に進展している。今年度は、AMS焦点面に設置するために開発した位置有感型放射線検出器の不感層を評価するための開発を行った。具体的には、16―64チャンネルの電極を持つシリコン半導体検出器に241Amからのα線を自動で0度と45度の方向からスキャンし、入射角の違いによるエネルギーピークの差から不感層を評価できるシステムを構築した。また、モンテカルロシミュレーションコードPHITSを用いた比較を行い、その結果を比較することで各ピクセルの不感層厚を求める手法を確立した。
    国産樹木単年輪中からの14Cスパイク検出の研究については、青森県下北半島から採取されたアスナロ試料の測定を行った。使用したアスナロは年輪年代が西暦1191年から1330年、1329年から1450年のサンプルであり、各サンプルから1年輪試料を剥離し、化学処理を施して試料から不純物を取り除く作業を行ったのち、塩素漂白、濃アルカリ処理によってα-セルロース抽出を行った。そしてセルロース試料に対してAMS分析を行い、14Cスパイクイベントの探索を行った。また、14Cスパイク年代測定方法の文化財試料への応用研究については、唐古・鍵遺跡から出土した炭化物試料について、AMS測定を開始した。
    コンパクトAMS用に開発した64チャンネルの電極を持つシリコン半導体の不感層の厚み、エネルギー分解能、そして位置分解能を専用に開発したα線源スキャン装置を用いて調べる。そして、AMS装置の焦点面に設置して、試料が装填されたカソード位置(最大40個)に対する14濃度の位置依存性および測定回数に対する変動を調べ、十分な統計精度(~0.1%)と低い系統誤差(~0.05%以下)による0.15%精度の14C分析を目標に開発研究を行う。
    国産樹木単年輪中からの14Cスパイク検出の研究については、アスナロ試料の単年輪の他、新しく年輪年代が決定した天童若松寺1000年杉を対象に14C濃度測定を行い、スパイク検出の他、太陽活動のシュワベサイクルがその濃度分布から確認できるか研究を行う。
    また、14Cスパイク年代測定方法の文化財試料への応用研究については、引き続き唐古・鍵遺跡から出土した木材についてAMSを用いた14C濃度測定を行う。

  8. 多核種分析による完新世の極端太陽現象の頻度と規模解明

    Grant number:20H00173  2020.4 - 2021.3

    科学研究費助成事業  基盤研究(A)

    三宅 芙沙, 堀内 一穂, 宮原 ひろ子, 笹 公和, 箱崎 真隆, 前原 裕之, 木村 勝彦, 門叶 冬樹, 早川 尚志

      More details

    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\45110000 ( Direct Cost: \34700000 、 Indirect Cost:\10410000 )

    樹木年輪の14Cや氷床コアの10Be、36Clといった宇宙線生成核種は、観測史上最大とされ
    る1956年のSEP(Solar Energetic Particle)イベントの数十倍という過去の超巨大SEPイ
    ベントの優れた代替データである。本研究は、主に年輪の14C分析から、完新世(
    過去1万2千年間)における最大のSEPイベントの同定と、超巨大SEPイベントの発生頻度及
    びその発生特性の解明を目的とする。我々の太陽における発生特性を、太陽型恒星の恒星
    フレアと比較することで、太陽型恒星における太陽の普遍性と特殊性を評価する。
    樹木年輪の炭素14や氷床コアのベリリウム10、塩素36といった宇宙線生成核種は、直接観測で見つかっている最大のSEP(Solar Energetic Particle)イベントの数十倍という過去の超巨大SEPイベントの優れた代替データである。これまでに我々の宇宙線生成核種の分析から、775年や994年などの超巨大SEPイベントの痕跡を発見した(Miyake et al. 2012, 2013)。これは、我々の太陽でスーパーフレアが発生した可能性を示すだけでなく、現代社会に甚大な影響を与え得る極端太陽現象が将来発生する可能性を示すものである。本研究は、宇宙線生成核種の分析から、完新世(過去1万2千年間)における最大のSEPイベントの同定と、超巨大SEPイベントの発生頻度及びその発生特性の解明を目的とする。
    今年度は、長期的な樹木年輪の炭素14分析を実施するために、樹木試料の手配(日本、フィンランド、カリフォルニア産の樹木サンプル)や、試料調製装置(木片試料からグラファイト試料の抽出)の性能チェック、さらに分析に必要な環境作りを行った。また、SEPイベントのエネルギースペクトルを評価する上で要となる塩素36の(南極ドームふじ氷床コア)分析を行った。さらに、トラバーチン堆積物のベリリウム10データに過去の大規模SEPイベントがみられるか調査する足掛かりとして、トラバーチン分析を行うための環境整備を行った。
    令和2年度が最終年度であるため、記入しない。
    令和2年度が最終年度であるため、記入しない。

  9. 高解像度マルチアーカイブ分析による太陽地磁気変動史と宇宙線イベントの解明

    Grant number:19H00706  2019.4 - 2023.3

    科学研究費助成事業  基盤研究(A)

    堀内 一穂, 三宅 芙沙, 宮原 ひろ子, 川村 賢二, 山崎 俊嗣, 小田 啓邦, 笹 公和

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    Authorship:Coinvestigator(s)  Grant type:Competitive

    研究代表者らは、アイスコアや堆積物および年輪などのマルチアーカイブに含まれる宇宙線生成核種を対比に利用した「宇宙線層序」を開拓することで、限られた区間とは言え、宇宙線強度の高解像度でロバストな変動曲線を得ることに成功した。この手法で得られた曲線は、過去の太陽活動や地磁気強度変動、さらには様々な突発的宇宙線イベントを解明する手がかりとなる。本研究ではこの手法を発展させ、さらなる宇宙線生成核種記録の獲得と宇宙線層序による海陸の詳細対比を目指す。さらにこれに基づいて、地質時代の太陽活動・地磁気強度変動史を解明するとともに、未知の宇宙線イベントを見いだす。
    南極ドームふじアイスコアを利用して、酸素同位体ステージ6の百年解像度ベリリウム10分析を行った。また、同コアの数値年代を主にガス分析に基づいて向上させるとともに、ガス分析融解水のベリリウム10分析を継続した。さらに、南極大陸でのベリリウム10の時空間分布を正確に把握するために、第63次南極地域観測隊に同行者(大谷 昂)を派遣し、表層積雪の採取を行った。これらに加えて、太平洋とインド洋の海底堆積物を対象にした地磁気極小期の高時間解像度ベリリウム同位体分析を行った。堆積物から得られたデータは、古地磁気強度変動記録やドームふじアイスコアのベリリウム10記録と、逐次比較された。こうした試みにより、地質時代の太陽活動と地磁気変動史の詳細解明に資するデータを得ることができた。
    単年解像度での分析が必要な完新世の宇宙線イベントに関して、紀元前約5500年の特異な太陽極小期の性質を、ドームふじアイスコアを対象とした単年解像度でのベリリリウム10分析や数年解像度での塩素36分析により明らかにし、論文として公表した。また、下北半島猿ケ森埋没林の炭素14分析により、13世紀に少なくとも3回の巨大太陽嵐イベントが起こっていた事実を発見し、これも論文として公表した。さらに、中国雲南省の陸域炭酸塩堆積物(トラバーチン)を対象に、単年解像度のベリリウム10分析を行った。こうした試みにより、過去数千年間の短期宇宙線イベントに関する情報が集積しつつあり、これを鍵として、より古い時代のイベントを解明するための重要な手がかりが得られつつある。
    以上の結果を含めた関連する成果について、国際学会での発表や論文での公表を行った。また最終年度の研究に備えて、試料の分取や成果のまとめに向けた研究打ち合わせを実施した。
    本事業は大きく分けて、(1)過去50万年間の高解像度宇宙線生成核種記録の獲得と宇宙線層序による海陸の詳細対比、(2)宇宙線層序に挿入する数値年代の向上、(3)太陽活動・地磁気変動史の詳細解明、(4)未知宇宙線イベントの探索と発見、(5)宇宙線層序編年の高度化と拡張を目標としている。昨年度に引き続いて本年度も、新型コロナウイルスの影響で、アイスコア試料の分取や研究成果の公表に一部停滞を余儀なくされたが、他の事項は順調に進行した。
    計画の遂行に大きな問題は生じていないことから、当初の計画通り課題を推進する予定である。

  10. Radiocarbon measurement of annual tree-ring to clarify regional effect and fine structure on calibration curve

    Grant number:18H03594  2018.4 - 2022.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    Sakamoto Minoru

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    Authorship:Coinvestigator(s)  Grant type:Competitive

    We conducted annual 14C dating of tree rings from Japan and the Korean Peninsula, which had been dated by dendrochronology including oxygen isotope methods. Japanese tree rings tend to show older 14C dates than those from Europe and the U.S., but trees from Kyushu during the beginning of the Yayoi period have a meandering calibration curve relative to IntCal, which may affect the age calibration. The calibration curve for the 1st to 3rd century was revised to IntCal20 following the adoption of the Japanese tree-ring data, but the tree rings from the southern coast of the Korean peninsula do not match the IntCal20 curve. The 14C age behavior of Japanese tree rings may be a rather peculiar regional effect. Together with the previously reported results, which have been developed using five tree rings as a single source, 14C ages of Japanese tree rings have been accumulated for the past 3,000 years.

  11. Occurrence rate of extreme SPEs for the last 5000 years

    Grant number:16H06005  2016.4 - 2020.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (A)

    Miyake Fusa

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\23920000 ( Direct Cost: \18400000 、 Indirect Cost:\5520000 )

    Large-scale Solar Proton Events (SPEs), originate from solar flares and coronal mass ejections, can cause enormous damage such as a breakdown of artificial satellites. Although the large-scale SPEs have been observed directly for the past ~70 years, the longer-term characteristics of SPE (e.g., their occurrence rate and upper limit) are not well understood. The purpose of this study is to investigate the signatures of large-scale SPEs occurred in the past by measuring the 14C concentration of tree rings, which is a proxy for large-scale SPE, with a one-year resolution and capturing a rapid increases in 14C concentrations. We aim to clarify the occurrence rate of large-scale SPEs and the relationship between the occurrence of large-scale SPEs and solar activity.

  12. Repetitive 14C measurements for understanding of occurrence distribution of extreme SPEs in the 7-10th centuries

    Grant number:16K13802  2016.4 - 2019.3

    Miyake Fusa

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\3640000 ( Direct Cost: \2800000 、 Indirect Cost:\840000 )

    Rapid 14C increase events have been discovered in 774-775 and 993-994 CE by continuous 14C concentration measurements of tree rings. The most plausible cause of these 14C increase events are an extreme Solar Proton Event (SPE). Such extreme SPEs cause the destruction of satellites and terrestrial communication networks, and can be a natural disaster in modern society comparable to huge eruptions and earthquakes. The purpose of this study is to detect more 14C increase events smaller than the 775 and 994 events by an ultra-high precision measurement of 14C concentrations in annual tree rings for the period 600-1000 CE, and clarify an occurrence rate of 14C events. Although we detected some smaller 14C events, further validation will be necessary to identify the extreme SPE origins.

  13. 宇宙線生成核種を用いた過去2500年の巨大SPE調査

    2014.4 - 2016.3

    科学研究費補助金 

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    Authorship:Principal investigator 

  14. 樹木年輪中放射性炭素14濃度測定による過去の宇宙線強度の復元

    2012.4 - 2014.3

    科学研究費補助金 

      More details

    Authorship:Principal investigator 

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Teaching Experience (On-campus) 7

  1. Paleo Cosmic Ray Physics

    2020

  2. 物理学実験I

    2020

  3. 物理学実験II

    2020

  4. Cosmic-ray Physics Seminar 4

    2020

  5. 地球学

    2020

  6. 太陽地球系科学

    2020

  7. 宇宙科学

    2020

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Social Contribution 28

  1. 中日文化センター 巨大太陽フレアと地球環境

    Role(s):Lecturer

    2018.3

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    Audience: Junior students, High school students, College students, Graduate students, Teachers, Guardians, General

    Type:Lecture

  2. 麗澤瑞浪 中学・高等学校 研究室紹介

    Role(s):Lecturer

    2017.11

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    Audience: Junior students, High school students

    Type:Other

  3. わかりやすい科学 「科学のたまご」を君のこころに 科学講座

    2017.2

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    Audience: Schoolchildren, Guardians

    Type:Lecture

  4. 小・中学生向け夏休み体験学習「樹木年輪・年縞堆積物から過去の太陽活動、地球の古気候を探る」

    Role(s):Lecturer

    2016.8

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    Audience: Schoolchildren, Junior students

    Type:Lecture

  5. 名古屋大学宇宙地球環境研究所公開講演会「嵐を測る」

    Role(s):Lecturer

    2016.7

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    Audience: General

    Type:Lecture

  6. 駿台天文講座

    2015.9

  7. サロン・ド・Arimoto

    2014.10

  8. 愛知県図書館サイエンスセミナー

    2014.8

  9. 名古屋市科学館公開セミナー

    2014.8

  10. 南山高等・中学校女子部 理科講演会

    2014.7

  11. 岡崎ロータリークラブ創立63周年記念例会

    2014.6

  12. 昭和高校文化講演会

    2014.3

  13. さかえサイエンストーク

    2012.10

  14. 太陽面爆発の歴史を探るはなし

    Role(s):Lecturer

    名古屋大学  名古屋大学オープンレクチャー  2022.3

  15. 屋久杉に刻まれた過去の太陽活動

    Role(s):Lecturer

    仁科記念講演会「アイソトープで探る宇宙」  2018.11

  16. 古木に記された過去の巨大太陽フレアー

    Role(s):Lecturer

    中日文化センター  巨大太陽フレア―と地球環境  2018.3

  17. 過去の太陽と樹木年輪

    Role(s):Lecturer

    名古屋大学  小・中学生向け夏休み体験学習「樹木年輪・年縞堆積物から過去の太陽活動、地球の古気候を探る」  2016.8

  18. 過去の太陽嵐を探る

    Role(s):Lecturer

    名古屋大学宇宙地球環境研究所公開講演会「嵐を測る」  2016.7

  19. 宇宙線の歴史を屋久杉で探る

    Role(s):Lecturer

    駿台天文講座  2015.9

  20. 樹木年輪から探る過去の宇宙線変動

    Role(s):Lecturer

    サロン・ド・Arimoto  2014.10

  21. 屋久杉に刻まれた謎の放射線バースト

    Role(s):Lecturer

    名古屋市科学館  公開セミナー  2014.8

  22. 屋久杉を用いた過去の宇宙線観測

    Role(s):Lecturer

    愛知県図書館  サイエンスセミナー  2014.8

  23. 屋久杉が語る過去の宇宙線急増イベント

    Role(s):Lecturer

    南山高等・中学校女子部  理科講演会  2014.7

  24. 屋久杉が語る過去の太陽活動

    Role(s):Lecturer

    名大祭太陽研講演会  2014.6

  25. 屋久杉に記録された奈良・平安時代の放射線バースト

    Role(s):Lecturer

    岡崎ロータリークラブ創立63周年記念例会  2014.6

  26. 屋久杉が語る過去の宇宙線急増イベント

    Role(s):Lecturer

    昭和高校  文化講演会  2014.3

  27. NHKBS

    Role(s):Media coverage

    コズミックフロント  2013

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    Audience: Media

    Type:TV or radio program

  28. 屋久杉が語る奈良時代の宇宙線強度~急激な増加の謎~

    Role(s):Lecturer

    さかえサイエンストーク  2012.10

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Media Coverage 1

  1. コズミック フロント☆NEXT

    2018.5