Abstract

Isotope and concentration measurements are reported for CO and CH4 in air collected in the upper troposphere and lower stratosphere between New Zealand and Antarctica in October 1993. The 13C/12C ratio of CO for the stratospheric samples, which are identified using calculated potential vorticity and coherent isotope data, like the abundance of 14CO molecules, are much lower than all previously reported atmospheric values. The measurements manifest a very steep decrease in δ13C with declining CO, with one sample reaching a δ13C value relative to V‐PDB of −43‰ at 20 ppbv CO. This large isotope shift is caused by the local production of several ppbv of extremely depleted CO. Not only is C4 itself a 13C depleted precursor of CO, it is specifically the recently discovered large fractionation in Cl+CH4, and the availability of free Cl during ozone hole conditions, which causes the effect.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.