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Quantifying the Imprints of Stratospheric Contributions to Interhemispheric Differences in Tropospheric CFC‐11, CFC‐12, and N 2 O Abundances
Author(s) -
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
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl093700
Subject(s) - stratosphere , troposphere , tropopause , atmospheric sciences , tracer , flux (metallurgy) , trace gas , environmental science , atmospheric chemistry , climatology , chemistry , geology , physics , ozone , meteorology , organic chemistry , nuclear physics
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 N 2 O. We employ a chemistry climate model along with satellite and global surface station observations. Our model explains 60% of observed N 2 O 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.