Faculty Profiles - MIYAKE Fusa

Papers - MIYAKE Fusa

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Transient Offset in <sup>14</sup>C After the Carrington Event Recorded by Polar Tree Rings Reviewed Open Access

Joonas Uusitalo, Kseniia Golubenko, Laura Arppe, Nicolas Brehm, Thomas Hackman, Hisashi Hayakawa, Samuli Helama, Kenichiro Mizohata, Fusa Miyake, Harri Mäkinen, Pekka Nöjd, Eija Tanskanen, Fuyuki Tokanai, Eugene Rozanov, Lukas Wacker, Ilya Usoskin, Markku Oinonen

Geophysical Research Letters Vol. 51 ( 5 ) 2024.3

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

Abstract

The Carrington event of 1859 has been the strongest solar flare in the observational history. It plays a crucial role in shedding light on the frequency and impacts of the past and future Solar Energetic Particle (SEP) events on human societies. We address the impact of the Carrington event by measuring tree‐ring <sup>14</sup>C with multiple replications from high‐latitude locations around the event and by comparing them with mid‐latitude measurements. A transient offset in <sup>14</sup>C following the event is observed with high statistical significance. Our state‐of‐the‐art <sup>14</sup>C production and transport model does not reproduce the observational finding, suggesting features beyond present understanding. Particularly, our observation would require partially fast transport of <sup>14</sup>C between the stratosphere and troposphere at high latitudes. The observation is consistent with the previous findings with the SEP events of 774 and 993 CE for which faster integration of <sup>14</sup>C into tree rings is observed at high latitudes.

DOI： 10.1029/2023GL106632

No signature of extreme solar energetic particle events in high-precision 14C data from the Alaskan tree for 1844–1876 CE Invited Reviewed Open Access

Fusa Miyake, Masataka Hakozaki, Hisashi Hayakawa, Naruki Nakano, Lukas Wacker

Journal of Space Weather and Space Climate Vol. 13 2023.12

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

Cosmogenic nuclides—14C from tree rings and 10Be & 36Cl from ice cores serve as an effective proxy for past extreme solar energetic particle (SEP) events. After identifying the first signature of an extreme SEP event in 774 CE, several candidates have been found in these proxy archives, such as 993 CE, 660 BCE, and 7176 BCE. Their magnitudes have been estimated to be tens of times larger than that of the largest SEP event ever observed since 1950s. Although a detailed survey of such extreme SEP events is ongoing, the detection of intermediate-sized SEP events that bridge the gap between modern observations and extreme events detected in cosmogenic nuclides has not progressed sufficiently, primarily because of the uncertainties in cosmogenic nuclide data. In this study, we measured 14C concentrations in tree rings in the 19th century (1844–1876 CE) to search for any increases in 14C concentrations corresponding to intermediate-size extreme SEP events. We utilized Alaskan tree-ring samples cut into early and latewoods to suppress the potential seasonal variations in intra-annual 14C data. Notably, no significant 14C variations were observed between early and latewoods (0.0 ± 0.3‰), and the annual resolution 14C data series displayed an error of ~0.8‰. Over the entire study period, no significant increase in 14C concentrations characterized by other candidates of extreme SEP events such as the 774 CE event was detected in the annual 14C data. The present result imposes a constraint on the SEP fluence when the largest-class of recorded solar storms occurred (especially those in 1859 CE and 1872 CE).

DOI： 10.1051/swsc/2023030

Extreme Solar Events: Setting up a Paradigm Reviewed Open Access

Ilya Usoskin, Fusa Miyake, Melanie Baroni, Nicolas Brehm, Silvia Dalla, Hisashi Hayakawa, Hugh Hudson, A. J. Timothy Jull, Delores Knipp, Sergey Koldobskiy, Hiroyuki Maehara, Florian Mekhaldi, Yuta Notsu, Stepan Poluianov, Eugene Rozanov, Alexander Shapiro, Tobias Spiegl, Timofei Sukhodolov, Joonas Uusitalo, Lukas Wacker

Space Science Reviews Vol. 219 ( 8 ) 2023.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

The Sun is magnetically active and often produces eruptive events on different energetic and temporal scales. Until recently, the upper limit of such events was unknown and believed to be roughly represented by direct instrumental observations. However, two types of extreme events were discovered recently: extreme solar energetic particle events on the multi-millennial time scale and super-flares on sun-like stars. Both discoveries imply that the Sun might rarely produce events, called extreme solar events (ESE), whose energy could be orders of magnitude greater than anything we have observed during recent decades. During the years following these discoveries, great progress has been achieved in collecting observational evidence, uncovering new events, making statistical analyses, and developing theoretical modelling. The ESE paradigm lives and is being developed. On the other hand, many outstanding questions still remain open and new ones emerge. Here we present an overview of the current state of the art and the forming paradigm of ESE from different points of view: solar physics, stellar–solar projections, cosmogenic-isotope data, modelling, historical data, as well as terrestrial, technological and societal effects of ESEs. Special focus is paid to open questions and further developments. This review is based on the joint work of the International Space Science Institute (ISSI) team #510 (2020–2022).

DOI： 10.1007/s11214-023-01018-1

Other Link： https://link.springer.com/article/10.1007/s11214-023-01018-1/fulltext.html

Regional Differences in Carbon-14 Data of the 993 CE Cosmic Ray Event Reviewed Open Access

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

Frontiers in Astronomy and Space Sciences Vol. 9 2022.7

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

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

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

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

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

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

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

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

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

Authorship：Corresponding author 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

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 Open Access

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

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

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

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

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

SEARCH FOR ANNUAL C-14 EXCURSIONS IN THE PAST Reviewed International journal Open Access

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

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

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

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

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 >= 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

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

F. Miyake, K. Masuda, T. Nakamura

Nature Communications 2013

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

The Solar and Geomagnetic Storms in 2024 May: A Flash Data Report

Hayakawa, H; Ebihara, Y; Mishev, A; Koldobskiy, S; Kusano, K; Bechet, S; Yashiro, S; Iwai, K; Shinbori, A; Mursula, K; Miyake, F; Shiota, D; Silveira, MVD; Stuart, R; Oliveira, DM; Akiyama, S; Ohnishi, K; Ledvina, V; Miyoshi, Y

ASTROPHYSICAL JOURNAL Vol. 979 ( 1 ) 2025.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Astrophysical Journal

In 2024 May, the scientific community observed intense solar eruptions that resulted in a great geomagnetic storm and auroral extensions, highlighting the need to document and quantify these events. This study mainly focuses on their quantification. The source active region (AR; NOAA Active Region 13664) evolved from 113 to 2761 millionths of the solar hemisphere between May 4 and 14. NOAA AR 13664’s magnetic free energy surpassed 1033 erg on May 7, triggering 12 X-class flares on May 8-15. Multiple interplanetary coronal mass ejections (ICMEs) were produced from this AR, accelerating solar energetic particles toward Earth. According to satellite and interplanetary scintillation data, at least four ICMEs erupted from AR 13664, eventually overcoming and combining each other. The shock arrival at 17:05 UT on May 10 significantly compressed the magnetosphere down to ≈5.04 R E and triggered a deep Forbush Decrease. GOES satellite data and ground-based neutron monitors confirmed a ground-level enhancement from 2 UT to 10 UT on 2024 May 11. The ICMEs induced exceptional geomagnetic storms, peaking at a provisional Dst index of −412 nT at 2 UT on May 11, marking the sixth-largest storm since 1957. The AE and AL indices showed great auroral extensions that located the AE/AL stations into the polar cap. We gathered auroral records at that time and reconstructed the equatorward boundary of the visual auroral oval to 29.°8 invariant latitude. We compared naked-eye and camera auroral visibility, providing critical caveats on their difference. We also confirmed global disturbances of the storm-enhanced density of the ionosphere.

DOI： 10.3847/1538-4357/ad9335

The Role of Deposition of Cosmogenic <sup>10</sup>Be for the Detectability of Solar Proton Events Reviewed Open Access

K. Schaar, T. Spiegl, U. Langematz, T. Sato, F. Mekhaldi, M. Kunze, F. Miyake, S. Yoden

Journal of Geophysical Research: Atmospheres Vol. 129 ( 11 ) 2024.6

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

Abstract

The manifestation of extreme solar proton events (SPEs) in Beryllium‐10 (<sup>10</sup>Be) ice core data contains valuable information about the strength and incidence of SPEs or local characteristics of the atmosphere. To extract this information, the signals of enhanced production of cosmogenic <sup>10</sup>Be due to the SPEs have to be detected, hence distinguished from the variability of the background production by galactic cosmic rays (GCRs). Here, we study the transport and deposition of <sup>10</sup>Be from GCRs, using the ECHAM/MESSy Atmospheric Chemistry climate model, and discuss the detectability of extreme SPEs (similar to the CE 774/775 SPE) in <sup>10</sup>Be ice core data depending on the ice core location, seasonal appearance of the SPE, atmospheric aerosol size distribution and phase of the 11‐year solar cycle. We find that sedimentation can be a major deposition mechanism of GCR generated <sup>10</sup>Be, especially at high latitudes, depending on the aerosols to which <sup>10</sup>Be attaches after production. The comparison of our results to four ice core records of <sup>10</sup>Be from Greenland and Antarctica shows good agreement for both <sup>10</sup>Be from GCRs and solar energetic particles (SEP). From our results we deduce that the location of detection and the season of occurrence of the SPE have a considerable effect on its detectability, as well as the aerosol size distribution the produced cosmogenic nuclides meet in the atmosphere. Furthermore, we find that SPEs occurring in the phase of highest activity during the 11‐year solar cycle are more detectable than SPEs that arise in the phase of lowest activity.

DOI： 10.1029/2023JD040463

Exploring past solar eruptions using cosmogenic nuclides

Fusa Miyake

Abstracts of Annual Meeting of the Geochemical Society of Japan Vol. 71 ( 0 ) page： 101 2024

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

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

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

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

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

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 Reviewed Open Access

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

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

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

14C分析による過去の極端太陽面爆発の調査

三宅芙沙

日本原子力学会誌 Vol. 65 page： 34 - 37 2023

Investigation of extreme solar energetic particle events in the past 10,000years

Proceedings of the 23rd Japanese Symposium on Accelerator Mass Spectrometry JAMS-23 2023

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

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

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

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

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

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

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

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.

Cosmogenic Evidence for Past SEP Events

Miyake F.

Proceedings of Science Vol. 358 2021.7

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.

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

Language：English 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.

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

Findings from an in-Depth Annual Tree-Ring Radiocarbon Intercomparison Reviewed International coauthorship International journal Open Access

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

Language：English 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

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

Measurements of Radionuclides International journal

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

EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN 2020

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

Extreme Solar Particle Storms The hostile Sun Introduction International journal

Usoskin I, Miyake F

EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN 2020

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

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

Past cosmic-ray increase events detected from high-precision 14C data Invited Reviewed

Fusa Miyake

Hoshasen Vol. 45 ( 3 ) page： 144 - 149 2020

Radiocarbon Production Events and their Potential Relationship with the Schwabe Cycle Reviewed International journal Open Access

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

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

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

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

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

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

Cosmogenic Evidence for Past SEP Events International journal

MIYAKE Fusa

Proc. 36th International Cosmic Ray Conference 2019.8

Annual variation of cosmic ray intensities for the past 3,000 years International journal

Proceedings of the 20th Japanese Symposium on Accelerator Mass Spectrometry ( 2018-002 ) page： 83 - 86 2019.2

Cosmogenic evidence for past SEP events International journal

Miyake F.

Proceedings of Science Vol. 358 2019

Language：English 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.

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

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

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.

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

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

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

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

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 Open Access

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

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

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

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

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

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

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

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：GEOCHEMICAL SOCIETY OF JAPAN

<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

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

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

SUPERNOVAE AND SINGLE-YEAR ANOMALIES IN THE ATMOSPHERIC RADIOCARBON RECORD Reviewed International journal Open Access

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

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

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

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

Atmospheric impacts of the strongest known solar particle storm of 775 AD Reviewed International journal Open Access

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

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

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

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

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

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

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

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

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

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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