@article{82566e80b001468eb6b487293429f7fc,
title = "Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. (∼660 BC)",
abstract = " Recently, it has been confirmed that extreme solar proton events can lead to significantly increased atmospheric production rates of cosmogenic radionuclides. Evidence of such events is recorded in annually resolved natural archives, such as tree rings [carbon-14 ( 14 C)] and ice cores [beryllium-10 ( 10 Be), chlorine-36 ( 36 Cl)]. Here, we show evidence for an extreme solar event around 2,610 years B.P. (∼660 BC) based on high-resolution 10 Be data from two Greenland ice cores. Our conclusions are supported by modeled 14 C production rates for the same period. Using existing 36 Cl ice core data in conjunction with 10 Be, we further show that this solar event was characterized by a very hard energy spectrum. These results indicate that the 2,610-years B.P. event was an order of magnitude stronger than any solar event recorded during the instrumental period and comparable with the solar proton event of AD 774/ 775, the largest solar event known to date. The results illustrate the importance of multiple ice core radionuclide measurements for the reliable identification of short-term production rate increases and the assessment of their origins.",
keywords = "Ice cores, Radionuclides, Solar proton events, Solar storms",
author = "Paschal O{\textquoteright}Hare and Florian Mekhaldi and Florian Adolphi and Grant Raisbeck and Ala Aldahan and Emma Anderberg and J{\"u}rg Beer and Marcus Christl and Simon Fahrni and Synal, {Hans Arno} and Junghun Park and G{\"o}ran Possnert and John Southon and Edouard Bard and Raimund Muscheler",
note = "Funding Information: R.M.). F.A. was supported by Swedish Research Council Grant DNR2016-00218. J.P. was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources funded by the Ministry and Information and Communications Technology of Korea. NGRIP is directed and organized by the Center of Ice and Climate at the Niels Bohr Institute and the US NSF. It is supported by funding agencies and institutions in Belgium (Fonds de la Recherche Scientifique-Communaut{\'e} Fran{\c c}aise de Belgique and Research Foundation - Flanders), Canada (Natural Resources Canada/Geological Survey of Canada), China (Chinese Academy of Sciences), Denmark (Danish Natural Science Research Council and FIST), France [Institut Fran{\c c}ais pour la Recherche et la Technologie Polaires, Institut Polaire Fran{\c c}ais Paul Emile Victor, CNRS/Institut National des Sciences de l{\textquoteright}Univers (INSU), Commissariat {\`a} l{\textquoteright}{\'E}nergie Atomique, and Agence Nationale de la Recherche (ANR)], Germany (Alfred Wegener Institut), Iceland (The Icelandic Centre for Research), Japan (Ministry of Education, Culture, Sports, Science and Technology and National Institute of Polar Research), Korea (Korea Polar Research Institute), The Netherlands (Netherlands Organization for Scientific Research/Section Earth and Life Sciences), Sweden (Swedish Research Council and Swedish Polar Research Secretariat), Switzerland (Swiss National Science Foundation), the United Kingdom (Natural Environment Research Council), and the United States (US NSF Polar Programs). The French AMS national facility ASTER (CEREGE, Aix-en-Provence, France) is supported by the INSU/CNRS, the ANR through the “Projets th{\'e}matiques d{\textquoteright}excellence” Program for the “Equipements d{\textquoteright}excellence” ASTER-CEREGE action, and IRD. Funding Information: ACKNOWLEDGMENTS. We thank Carmen Vega for advice concerning the preparation of 10Be samples for AMS measurements. We also thank three anonymous reviewers and the editorial team for constructive comments on the manuscript. This work was supported by a Royal Physiographic Society of Lund grant (to F.M.) and Swedish Research Council Grant DNR2013-8421 (to Publisher Copyright: {\textcopyright} 2019 National Academy of Sciences. All Rights Reserved.",
year = "2019",
doi = "10.1073/pnas.1815725116",
language = "English",
volume = "116",
pages = "5961--5966",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "13",
}