Show simple item record

dc.contributor.authorCastagnoli, Giuliana
dc.contributor.authorLal, Devendra
dc.date.accessioned2021-02-11T19:31:42Z
dc.date.available2021-02-11T19:31:42Z
dc.date.issued1980-01-01
dc.identifier.citationCastagnoli, G., & Lal, D. (1980). Solar modulation effects in terrestrial production of carbon-14. Radiocarbon, 22(2), 133-158.
dc.identifier.issn0033-8222
dc.identifier.doi10.1017/S0033822200009413
dc.identifier.urihttp://hdl.handle.net/10150/652473
dc.description.abstractThis paper is concerned with the expected deviations in the production rate of natural 14C on the earth due to changes in solar activity. We review the published estimates of the global production rates of 14C due to galactic and solar cosmic ray particles, and present new estimates of the expected secular variations in 14C production, taking into account the latest information available on galactic cosmic ray modulation and long-term variations in solar activity. Estimated secular variations are related to data on atmospheric 14C/12C ratios based on tree rings. It is concluded that the observed higher frequency wiggles in atmospheric 14C/12C ratios occurring with time scales of about two hundred years and of 1 to 2 percent in magnitude (de Vries, 1958; Suess, 1970a,b; 1979; Damon, Lerman, and Long, 1978), are largely due to solar activity dependent modulation of the galactic cosmic ray flux by solar plasma. These variations override a slowly varying sinusoidal change of about 10 percent in magnitude during the last approximately 8000 years, which is believed to be primarily due to changes in the geomagnetic field. The high frequency modulation effect in 14C production is substantial, about 20 percent, which, considering the response function of the atmosphere (cf Houtermans, Suess, and Oeschger, 1973), is adequate to explain the observed 14C wiggles (also named Suess wiggles or de Vries oscillations) if in the past, periods of large modulation effects and also periods of weak modulation persisted, ie, the sun remained both active and inactive over long periods of time, of the order of several decades to centuries. The pioneering investigations of Eddy (1976; 1977) of the ancient records of solar activity make it plausible that the 14C wiggles in the ancient 14C/12C ratios are primarily due to modulation of galactic cosmic ray flux by a varying sun. Thus, the 14C wiggles are good indicators of solar activity in the past. We also present revised estimates of the production rates of 14C on the earth due to solar flare accelerated cosmic rays and limits of direct accretion of 14C on the earth.
dc.language.isoen
dc.publisherAmerican Journal of Science
dc.relation.urlhttp://radiocarbon.webhost.uits.arizona.edu/
dc.rightsCopyright © The American Journal of Science
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.titleSolar Modulation Effects in Terrestrial Production of Carbon-14
dc.typeArticle
dc.typetext
dc.identifier.journalRadiocarbon
dc.description.noteThis material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.
dc.description.collectioninformationThe Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform February 2021
dc.source.volume22
dc.source.issue2
dc.source.beginpage133
dc.source.endpage158
refterms.dateFOA2021-02-11T19:31:42Z


Files in this item

Thumbnail
Name:
601-852-1-PB.pdf
Size:
2.496Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record