edu.ucar.opensky::articles:18330 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T02:55:10.217617 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7qn68d5 Measurements and modeling of contemporary radiocarbon in the stratosphere 2016-02-16T00:00:00Z publication https://n2t.org/ark:/85065/d7qn68d5 https://doi.org/10.1002/2015GL066921 Kanu, A. author Comfort, L. author Guilderson, T. author Cameron-Smith, P. author Bergmann, D. author Atlas, E. author Schauffler, Sue author Boering, K. author UCAR/NCAR - Library publisher 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) x 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. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2016 American Geophysical Union. None eng geoscientificInformation