Using measurements of atmospheric 14CO in a global network to improve understanding of OH spatial and temporal variability

Abstract

The primary source of 14C-containing carbon monoxide (14CO) in the atmosphere is via 14C production from 14N by secondary cosmic rays, and the primary sink is removal by hydroxyl radicals (OH). Variations in the abundance of 14CO that are not explained by variations in 14CO production or transport are mainly driven by variations in the abundance of OH. Because of its relatively short atmospheric lifetime (≈2 months on average), 14CO abundance is sensitive to spatial and seasonal OH variability. 14CO measurements in a new global network were made for one calendar year in 2021. Simulations in the GEOS-Chem chemical transport model (CTM) indicate that our 14CO network has good sensitivity to variations in both regional and global OH. In this presentation, we will show the new measurements as well as the CTM results available to-date.