Deriving global mean OH and atmospheric lifetimes for ozone-depleting substances and greenhouse gases using observed CH3CCl3 and chemistry-climate models

Published

November 3, 2017

Author(s)

Vladimir L. Orkin, Qing Liang, Martyn P. Chipperfield, Matthew Rigby, Olaf Morgenstern, Guus J. Velders, Luke Abraham, Sandip Dhomse, Eric L. Fleming, Steven C. Hardiman, Daniela Iachetti, Charles H. Jackman, Douglas E. Kinnison, Giovanni Pitari, Eugene Rozanov, Andrea Stenke, Fiona Tummon, James B. Burkholder

Abstract

Tests using flux-based methyl chloroform (MCF) concentrations from four state-of-the-art chemistry-climate models (CCMs) in the two-dimensional 12-box Bayesian inversion model (IM) indicate that the 12-box IM provides a reasonable estimate of global mean tropospheric OH ([OH]GM) and MCF lifetime. The 12-box IM-retrieved [OH]GM and MCF lifetime are accurate within 3-6% with those calculated internally in the CCMs. CCMs show large variations in their OH abundance and distribution and in general overestimate [OH]GM. However, their calculated partial lifetimes for all investigated OH-removed species are very tightly correlated. Hence, we argue it is more accurate to derive lifetimes for long-lived gases using the 12-box IM lifetime estimate for a reference gas, e.g. MCF, and the CCM-based correlations than direct from the CCMs. As atmospheric MCF declines, HFC-152a appears to be the optimum alternative reference gas because of its 1.6-yr lifetime, and small uncertainties in emissions and its reactivity towards OH.

Citation

Geophysical Research Letters

Pub Type

Journals

Keywords

Hydroxyl, OH, lifetime, HFC-152a, modeling, greenhouse, methyl chloroform

Citation

Orkin, V. , Liang, Q. , Chipperfield, M. , Rigby, M. , Morgenstern, O. , Velders, G. , Abraham, L. , Dhomse, S. , Fleming, E. , Hardiman, S. , Iachetti, D. , Jackman, C. , Kinnison, D. , Pitari, G. , Rozanov, E. , Stenke, A. , Tummon, F. and Burkholder, J. (2017), Deriving global mean OH and atmospheric lifetimes for ozone-depleting substances and greenhouse gases using observed CH3CCl3 and chemistry-climate models, Geophysical Research Letters (Accessed December 2, 2024)