Quantifying the Imprints of Stratospheric Contributions to Interhemispheric Differences in Tropospheric CFC-11, CFC-12, and N2O Abundances

Publication Type:

Journal Article

Authors:

Lickley, Megan; Solomon, Susan; Kinnison, Doug; Krummel, Paul; Mühle, Jens; O'Doherty, Simon; Prinn, Ronald; Rigby, Matthew; Stone, Kane A.; Wang, Peidong; Weiss, Ray; Young, Dickon

Source:

Geophysical Research Letters, Volume 48, Issue 15, p.e2021GL093700 (2021)

ISBN:

0094-8276

URL:

https://doi.org/10.1029/2021GL093700

Abstract:

Abstract For trace gases destroyed in the stratosphere, mass flux across the tropopause can substantially influence observed surface hemispheric differences (NH-SH). Here, we quantify associations between observed stratospheric and tropospheric NH-SH growth rate anomalies of CFC-11, CFC-12, and N2O. We employ a chemistry climate model along with satellite and global surface station observations. Our model explains 60% of observed N2O NH-SH growth rate variability from 2005 to 2019, compared to 30% for CFC-11% and 40% for CFC-12, supporting evidence that unexpected anthropogenic emissions caused sustained positive NH-SH anomalies in these CFCs from 2012 to 2017. Between 2012 and 2015, the observed CFC-11 NH-SH difference grew by 1.7 ppt; our model explains 0.5 ± 0.1 ppt of this growth, but not the duration. Our model suggests that in the absence of further emission anomalies, new NH-SH positive tracer anomalies should have occurred in 2020, and predicts small negative anomalies in 2021.

Notes: