Measurements and modeling of contemporary radiocarbon in the stratosphere

A. M. Kanu, L. L. Comfort, T. P. Guilderson, P. J. Cameron-Smith, D. J. Bergmann, Elliot L Atlas, S. Schauffler, K. A. Boering

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Measurements of the 14C content of carbon dioxide in air collected by high-altitude balloon flights in 2003-2005 reveal the contemporary radiocarbon distribution in the northern midlatitude stratosphere, four decades after the Limited Test Ban Treaty restricted atmospheric testing of nuclear weapons. Comparisons with results from a 3-D chemical-transport model show that the 14CO2 distribution is now largely governed by the altitude/latitude dependence of the natural cosmogenic production rate, stratospheric transport, and propagation into the stratosphere of the decreasing radiocarbon trend in tropospheric CO2 due to fossil fuel combustion. From the observed correlation of 14CO2 with N2O mixing ratios, an annual global mean net flux of 14CO2 to the troposphere of 1.6(±0.4) × 1017‰ mol CO2 yr-1 and a global production rate of 2.2(±0.6) × 1026 atoms 14C yr-1 are empirically derived. The results also indicate that contemporary 14CO2 observations provide highly sensitive diagnostics for stratospheric transport and residence times in models.

Original languageEnglish (US)
Pages (from-to)1399-1406
Number of pages8
JournalGeophysical Research Letters
Volume43
Issue number3
DOIs
StatePublished - Feb 16 2016

Keywords

  • carbon cycle
  • carbon dioxide
  • cosmogenic radionuclides
  • radiocarbon
  • stratosphere
  • stratosphere-troposphere exchange

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Geophysics

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    Kanu, A. M., Comfort, L. L., Guilderson, T. P., Cameron-Smith, P. J., Bergmann, D. J., Atlas, E. L., Schauffler, S., & Boering, K. A. (2016). Measurements and modeling of contemporary radiocarbon in the stratosphere. Geophysical Research Letters, 43(3), 1399-1406. https://doi.org/10.1002/2015GL066921