Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018

Susan E. Strahan; Dan Smale; Anne R. Douglass; Thomas Blumenstock; James W. Hannigan; Frank Hase; Nicholas B. Jones; Emmanuel Mahieu; Justus Notholt; Luke D. Oman; Ivan Ortega; Mathias Palm; Maxime Prignon; John Robinson; Matthias Schneider; Ralf Sussmann; Voltaire A. Velazco

doi:10.1029/2020GL088567

Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018

Susan E. Strahan, Dan Smale, Anne R. Douglass, Thomas Blumenstock, James W. Hannigan, Frank Hase, Nicholas B. Jones, Emmanuel Mahieu, Justus Notholt, Luke D. Oman, Ivan Ortega, Mathias Palm, Maxime Prignon, John Robinson, Matthias Schneider, Ralf Sussmann, Voltaire A. Velazco

Atmospheric Composition Remote Sensing and Prediction

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21 Scopus citations

Abstract

Total columns of the trace gases nitric acid (HNO₃) and hydrogen chloride (HCl) are sensitive to variations in the lower stratospheric age of air, a quantity that describes transport time scales in the stratosphere. Analyses of HNO₃ and HCl columns from the Network for the Detection of Atmospheric Composition Change panning 77°S to 79°N have detected changes in the extratropical stratospheric transport circulation from 1994 to 2018. The HNO₃ and HCl analyses combined with the age of air from a simulation using the MERRA2 reanalysis show that the Southern Hemisphere lower stratosphere has become 1 month/decade younger relative to the Northern Hemisphere, largely driven by the Southern Hemisphere transport circulation. The analyses reveal multiyear anomalies with a 5- to 7-year period driven by interactions between the circulation and the quasi-biennial oscillation in tropical winds. This hitherto unrecognized variability is large relative to hemispheric transport trends and may bias ozone trend regressions.

Original language	English
Article number	e2020GL088567
Journal	Geophysical Research Letters
Volume	47
Issue number	17
DOIs	https://doi.org/10.1029/2020GL088567
State	Published - Sep 16 2020

Keywords

age of air
dynamical variability
stratospheric transport
transport trends

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10.1029/2020GL088567

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Strahan, S. E., Smale, D., Douglass, A. R., Blumenstock, T., Hannigan, J. W., Hase, F., Jones, N. B., Mahieu, E., Notholt, J., Oman, L. D., Ortega, I., Palm, M., Prignon, M., Robinson, J., Schneider, M., Sussmann, R., & Velazco, V. A. (2020). Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018. Geophysical Research Letters, 47(17), Article e2020GL088567. https://doi.org/10.1029/2020GL088567

@article{a971ef4f5d144431912709e3fb5b6672,

title = "Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018",

abstract = "Total columns of the trace gases nitric acid (HNO3) and hydrogen chloride (HCl) are sensitive to variations in the lower stratospheric age of air, a quantity that describes transport time scales in the stratosphere. Analyses of HNO3 and HCl columns from the Network for the Detection of Atmospheric Composition Change panning 77°S to 79°N have detected changes in the extratropical stratospheric transport circulation from 1994 to 2018. The HNO3 and HCl analyses combined with the age of air from a simulation using the MERRA2 reanalysis show that the Southern Hemisphere lower stratosphere has become 1 month/decade younger relative to the Northern Hemisphere, largely driven by the Southern Hemisphere transport circulation. The analyses reveal multiyear anomalies with a 5- to 7-year period driven by interactions between the circulation and the quasi-biennial oscillation in tropical winds. This hitherto unrecognized variability is large relative to hemispheric transport trends and may bias ozone trend regressions.",

keywords = "age of air, dynamical variability, stratospheric transport, transport trends",

author = "Strahan, \{Susan E.\} and Dan Smale and Douglass, \{Anne R.\} and Thomas Blumenstock and Hannigan, \{James W.\} and Frank Hase and Jones, \{Nicholas B.\} and Emmanuel Mahieu and Justus Notholt and Oman, \{Luke D.\} and Ivan Ortega and Mathias Palm and Maxime Prignon and John Robinson and Matthias Schneider and Ralf Sussmann and Velazco, \{Voltaire A.\}",

year = "2020",

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day = "16",

doi = "10.1029/2020GL088567",

language = "English",

volume = "47",

journal = "Geophysical Research Letters",

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Strahan, SE, Smale, D, Douglass, AR, Blumenstock, T, Hannigan, JW, Hase, F, Jones, NB, Mahieu, E, Notholt, J, Oman, LD, Ortega, I, Palm, M, Prignon, M, Robinson, J, Schneider, M, Sussmann, R & Velazco, VA 2020, 'Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018', Geophysical Research Letters, vol. 47, no. 17, e2020GL088567. https://doi.org/10.1029/2020GL088567

TY - JOUR

T1 - Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018

AU - Strahan, Susan E.

AU - Smale, Dan

AU - Douglass, Anne R.

AU - Blumenstock, Thomas

AU - Hannigan, James W.

AU - Hase, Frank

AU - Jones, Nicholas B.

AU - Mahieu, Emmanuel

AU - Notholt, Justus

AU - Oman, Luke D.

AU - Ortega, Ivan

AU - Palm, Mathias

AU - Prignon, Maxime

AU - Robinson, John

AU - Schneider, Matthias

AU - Sussmann, Ralf

AU - Velazco, Voltaire A.

PY - 2020/9/16

Y1 - 2020/9/16

N2 - Total columns of the trace gases nitric acid (HNO3) and hydrogen chloride (HCl) are sensitive to variations in the lower stratospheric age of air, a quantity that describes transport time scales in the stratosphere. Analyses of HNO3 and HCl columns from the Network for the Detection of Atmospheric Composition Change panning 77°S to 79°N have detected changes in the extratropical stratospheric transport circulation from 1994 to 2018. The HNO3 and HCl analyses combined with the age of air from a simulation using the MERRA2 reanalysis show that the Southern Hemisphere lower stratosphere has become 1 month/decade younger relative to the Northern Hemisphere, largely driven by the Southern Hemisphere transport circulation. The analyses reveal multiyear anomalies with a 5- to 7-year period driven by interactions between the circulation and the quasi-biennial oscillation in tropical winds. This hitherto unrecognized variability is large relative to hemispheric transport trends and may bias ozone trend regressions.

AB - Total columns of the trace gases nitric acid (HNO3) and hydrogen chloride (HCl) are sensitive to variations in the lower stratospheric age of air, a quantity that describes transport time scales in the stratosphere. Analyses of HNO3 and HCl columns from the Network for the Detection of Atmospheric Composition Change panning 77°S to 79°N have detected changes in the extratropical stratospheric transport circulation from 1994 to 2018. The HNO3 and HCl analyses combined with the age of air from a simulation using the MERRA2 reanalysis show that the Southern Hemisphere lower stratosphere has become 1 month/decade younger relative to the Northern Hemisphere, largely driven by the Southern Hemisphere transport circulation. The analyses reveal multiyear anomalies with a 5- to 7-year period driven by interactions between the circulation and the quasi-biennial oscillation in tropical winds. This hitherto unrecognized variability is large relative to hemispheric transport trends and may bias ozone trend regressions.

KW - age of air

KW - dynamical variability

KW - stratospheric transport

KW - transport trends

UR - https://www.scopus.com/pages/publications/85090864220

U2 - 10.1029/2020GL088567

DO - 10.1029/2020GL088567

M3 - Article

AN - SCOPUS:85090864220

SN - 0094-8276

VL - 47

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 17

M1 - e2020GL088567

ER -

Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018

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Keywords

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