scholarly journals Search for Annual 14C Excursions in the Past

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Fusa Miyake ◽  
Kimiaki Masuda ◽  
Toshio Nakamura ◽  
Katsuhiko Kimura ◽  
Masataka Hakozaki ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Tree Ring ◽  
Cosmic Ray ◽  
Solar Proton ◽  
The Past ◽  
Continuous Measurements ◽  
Pine Tree ◽  
Short Timescale ◽  
Bristlecone Pine ◽  
Solar Proton Events

AbstractTwo 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 14C excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the 14C contents in bristlecone pine tree-ring samples during the periods when the rate of 14C 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 14C 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.

scholarly journals Large14C excursion in 5480 BC indicates an abnormal sun in the mid-Holocene

2017 ◽  
Vol 114 (5) ◽  
pp. 881-884 ◽  
Author(s):  
Fusa Miyake ◽  
A. J. Timothy Jull ◽  
Irina P. Panyushkina ◽  
Lukas Wacker ◽  
Matthew Salzer ◽  
...  
Keyword(s):  
Tree Rings ◽  
Time Resolution ◽  
Solar Minimum ◽  
Cosmic Ray ◽  
Solar Proton ◽  
The Past ◽  
Pine Tree ◽  
Unknown Phase ◽  
Increase Rate ◽  
Bristlecone Pine

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 of14C contents in tree rings with ≥10-y time resolution for the Holocene, there are few annual14C data. There is a little understanding about annual14C variations in the past, with the exception of a few periods including the AD 774−77514C excursion where annual measurements have been performed. Here, we report the result of14C 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 large14C increase (20‰) from 5481 BC to 5471 BC (the 5480 BC event). The14C 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.

Detection of solar proton events by using radiocarbon in tree-rings

2020 ◽  
Author(s):  
Nicolas Brehm ◽  
Marcus Christl ◽  
Hans-Arno Synal ◽  
Raimund Muscheler ◽  
Florian Adolphi ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Tree Ring ◽  
Tree Rings ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Galactic Cosmic Rays ◽  
The Sun ◽  
Cosmogenic Radionuclides ◽  
Cosmogenic Nuclide ◽  
Solar Proton Events

<p>Our Sun erratically expels large amounts of energetic particles into the interplanetary space and towards Earth, which can be observed as so-called solar proton events (SPE). A strong SPE might cause major damage to satellites and could even disrupt transformers at the ground<sup>1</sup>. This rises the questions how often strong SPEs occur. Since direct observations of SPEs are limited to the last decades, cosmogenic radionuclides can be used to detect such events further back in time. The production rate of cosmogenic nuclides, such as radiocarbon, is primarily dependent on the incoming flux of highly energetic galactic cosmic rays (GCR). Under normal conditions, the Sun’s magnetic field carried by the (low energy) solar protons shields us from (high energy) GCRs, resulting in a lower production of cosmogenic radionuclides when the Sun is active. During a SPE, however, the sudden and drastic increase of high the energy solar protons themselves may lead to an elevated production of cosmogenic radionuclides on Earth. Only recently, such sharp increases in cosmogenic nuclide production occurring within less than one year have been detected in several radionuclide records (<sup>10</sup>Be, <sup>36</sup>Cl, <sup>14</sup>C) from ice core and tree ring records, and have been attributed to SPEs<sup>2,3</sup>.</p><p>Until now, only three SPE could confidently be detected in cosmogenic radionuclide records<sup>1,4,5</sup>. The reason for this is a general lack of accurately dated and annually resolved radionuclide records and/or the strong dampening of the production signal e.g. by the carbon cycle. To find and identify such events we measured radiocarbon in tree ring records at annual resolution with accelerator mass spectrometry (AMS). In this new, accurately dated and annually resolved <sup>14</sup>C record spanning the past about 1000 yr we found several new candidates for SPEs. Their timing and amplitude in terms of cosmogenic nuclide production was characterized by using a global carbon cycle box model. Once unambiguously identified such spiked production increases recorded in the absolutely dated tree ring record have a great potential to be used as a global tool to synchronize other not well dated (climate) records with cosmogenic radionuclides (e.g. <sup>10</sup>Be, <sup>36</sup>Cl).</p><p>1              Schrijver, C. J. et al. (2012) Estimating the frequency of extremely energetic solar events, based on solar, stellar, lunar, and terrestrial records. Journal of Geophysical Research: Space Physics <strong>117</strong></p><p>2              Miyake, F., Masuda, K. & Nakamura, T. (2013) Another rapid event in the carbon-14 content of tree rings. Nature communications <strong>4</strong>, 1748</p><p>3              Mekhaldi, F. et al. (2015) Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4. Nature Communications <strong>6</strong>, 8611</p><p>4              Miyake, F., Nagaya, K., Masuda, K. & Nakamura, T. A (2012) signature of cosmic-ray increase in AD 774-775 from tree rings in Japan. Nature <strong>486</strong>, 240-242</p><p>5              O'Hare, P. et al. (2019) Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. ( approximately 660 BC). Proc Natl Acad Sci U S A <strong>116</strong>, 5961-5966</p>

Solar proton events during the past three solar cycles

1989 ◽  
Vol 26 (6) ◽  
pp. 403-415 ◽  
Author(s):  
D. F. Smart ◽  
M. A. Shea
Keyword(s):  
Solar Proton ◽  
Solar Cycles ◽  
The Past ◽  
Solar Proton Events

Atmospheric production and transport of 7Be activity by cosmic rays: Modelling with the chemistry-climate model SOCOLv3.0 and comparison with direct measurements

2021 ◽  
Author(s):  
Kseniia Golubenko ◽  
Eugene Rozanov ◽  
Genady Kovaltsov ◽  
Ari-Pekka Leppänen ◽  
Ilya Usoskin
Keyword(s):  
Cosmic Rays ◽  
Climate Changes ◽  
Climate Model ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Cosmogenic Isotopes ◽  
Cosmogenic Isotope ◽  
The Past ◽  
Direct Measurements ◽  
First Results

<p>We present the first results of modelling of the short-living cosmogenic isotope <sup>7</sup>Be production, deposition, and transport using the chemistry-climate model SOCOLv<sub>3.0</sub> aimed to study solar-terrestrial interactions and climate changes. We implemented an interactive deposition scheme,  based on gas tracers with and without nudging to the known meteorological fields. Production of <sup>7</sup>Be was modelled using the 3D time-dependent Cosmic Ray induced Atmospheric Cascade (CRAC) model. The simulations were compared with the real concentrations (activity) and depositions measurements of <sup>7</sup>Be in the air and water at Finnish stations. We have successfully reproduced and estimated the variability of the cosmogenic isotope <sup>7</sup>Be produced by the galactic cosmic rays (GCR) on time scales longer than about a month, for the period of 2002–2008. The agreement between the modelled and measured data is very good (within 12%) providing a solid validation for the ability of the SOCOL CCM to reliably model production, transport, and deposition of cosmogenic isotopes, which is needed for precise studies of cosmic-ray variability in the past. </p>

Bristlecone pine tree rings and volcanic eruptions over the last 5000 yr

2007 ◽  
Vol 67 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Matthew W. Salzer ◽  
Malcolm K. Hughes
Keyword(s):  
Tree Ring ◽  
Ice Core ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Pine Tree ◽  
Tree Ring Data ◽  
Pinus Longaeva ◽  
Bristlecone Pine ◽  
Ice Core Record ◽  
Pinus Aristata

AbstractMany years of low growth identified in a western USA regional chronology of upper forest border bristlecone pine (Pinus longaeva and Pinus aristata) over the last 5000 yr coincide with known large explosive volcanic eruptions and/or ice core signals of past eruptions. Over the last millennium the agreement between the tree-ring data and volcano/ice-core data is high: years of ring-width minima can be matched with known volcanic eruptions or ice-core volcanic signals in 86% of cases. In previous millennia, while there is substantial concurrence, the agreement decreases with increasing antiquity. Many of the bristlecone pine ring-width minima occurred at the same time as ring-width minima in high latitude trees from northwestern Siberia and/or northern Finland over the past 4000–5000 yr, suggesting climatically-effective events of at least hemispheric scale. In contrast with the ice-core records, the agreement between widely separated tree-ring records does not decrease with increasing antiquity. These data suggest specific intervals when the climate system was or was not particularly sensitive enough to volcanic forcing to affect the trees, and they augment the ice core record in a number of ways: by providing confirmation from an alternative proxy record for volcanic signals, by suggesting alternative dates for eruptions, and by adding to the list of years when volcanic events of global significance were likely, including the mid-2nd-millennium BC eruption of Thera.

Primary and secondary effects in cosmic-ray variations at solar proton events

2009 ◽  
Vol 73 (3) ◽  
pp. 325-327
Author(s):  
V. M. Dvornikov ◽  
M. V. Kravtsova ◽  
A. A. Lukovnikova ◽  
V. E. Sdobnov
Keyword(s):  
Cosmic Ray ◽  
Solar Proton ◽  
Secondary Effects ◽  
Primary And Secondary Effects ◽  
Solar Proton Events

scholarly journals Formation of large NAT particles and denitrification in polar stratosphere: possible role of cosmic rays and effect of solar activity

2004 ◽  
Vol 4 (1) ◽  
pp. 1037-1062 ◽  
Author(s):  
F. Yu
Keyword(s):  
Cosmic Rays ◽  
Strong Support ◽  
Ice Cores ◽  
Cosmic Ray ◽  
High Energy ◽  
Solar Proton ◽  
Arctic Regions ◽  
Secondary Ions ◽  
Selective Formation

Abstract. The formation of large nitric acid trihydrate (NAT) particles has important implications for denitrification and ozone depletion. Existing theories can't explain the recent observations of large NAT particles over wide Arctic regions at temperature above ice frost point. Our analyses reveal that high-energy comic rays may induce the freezing of supercooled HNO3−H2O–H2SO4 droplets when they penetrate these thermodynamically unstable droplets. The cosmic ray-induced freezing (CRIF) is consistent with the observed highly selective formation of NAT particles. We suggest that the physics behind the CRIF mechanism is the reorientation of polar solution molecules into the crystalline configuration in the strong electrical fields of moving secondary ions generated by passing cosmic rays. Our simulations indicate that strong solar proton events (SPEs) may significantly enhance the formation of large NAT particles and denitrification. The CRIF mechanism can explain the high correlations between the thin nitrate-rich layers in polar ice cores and major SPEs. The observed enhancement in aerosol backscattering ratio at PSC layers shortly after an SPE and the significant precipitation velocity of the enhanced PSC payers also provide strong support for the CRIF mechanism.

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