Seventeen years of ozone sounding at L'Aquila, Italy: evidence of mid-latitude stratospheric ozone recovery and tropospheric profile changes

Daniele Visioni (1) , Giovanni Pitari (2) , Vincenzo Rizi (2, 3) , Marco Iarlori (2, 3) , Irene Cionni (4) , Ilaria Quaglia (2) , Hideharu Akiyoshi (5) , Slimane Bekki (6) , Neal Butchart (7) , Martin Chipperfield (8) , Makoto Deushi (9) , Sandip S. Dhomse (8) , Rolando Garcia (10) , Patrick Joeckel (11) , Douglas Kinnison (10) , Jean-François Lamarque (10) , Marion Marchand (6) , Martine Michou (12) , Olaf Morgenstern (13) , Tatsuya Nagashima (5) , Fiona M. O'Connor (7) , Luke D. Oman (14) , David Plummer (15) , Eugene Rozanov (16) , David Saint-Martin (12) , Robyn Schofield (17) , John Scinocca (15) , Andrea Stenke (16) , Kane Stone (17) , Kengo Sudo (18) , Taichu Y. Tanaka (9) , Simone Tilmes (10) , Holger Tost (11) , Yousuke Yamashita (5) , Guang Zeng (13)

1 MAE - Sibley School of Mechanical and Aerospace Engineering
2 DSFC - Department of Physical and Chemical Sciences [L'Aquila]
3 Centre of Excellence CETEMPS
4 ENEA - Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development
5 NIES - National Institute for Environmental Studies
6 STRATO - LATMOS
7 MOHC - Met Office Hadley Centre for Climate Change
8 SEE - School of Earth and Environment [Leeds]
9 MRI - Meteorological Research Institute [Tsukuba]
10 NCAR - National Center for Atmospheric Research [Boulder]
11 IPA - DLR Institut für Physik der Atmosphäre
12 CNRM - Centre national de recherches météorologiques
13 NIWA - National Institute of Water and Atmospheric Research [Wellington]
14 GSFC - NASA Goddard Space Flight Center
15 Environment and Climate Change Canada
16 IAC - Institute for Atmospheric and Climate Science [Zürich]
17 School of Earth Sciences [Melbourne]
18 Graduate School of Environmental Studies [Nagoya]

Ozone profile measurements collected at L'Aquila (Italy, 42.4°N) during seventeen years of radio-sounding 30 (2000-2016) are presented here, with an analysis of derived trends. Model results from the SPARC-CCMI exercise are used in parallel to highlight the physical and chemical mechanisms regulating mid-latitude ozone trends. The statistically significant trends highlighted in time series at L'Aquila are those in the mid-upper stratosphere (+5.9±4.2), mid troposphere https://doi.org/10.5194/acp-2020-525 Preprint. Discussion started: 1 July 2020 c Author(s) 2020. CC BY 4.0 License. 2 (+5.9±2.4) and upper troposphere (+2.5±0.9), all in percent/decade. The upper stratospheric positive trend was already well documented in recent WMO assessments and attributed to the starting decline of stratospheric Cly and Bry and to the 35 stratospheric cooling induced by increasing well mixed greenhouse gases, thus slowing down gas-phase reactions that destroy ozone in the upper stratosphere. The ozone increase in the mid-upper troposphere is largely regulated by the increasing strength of the Brewer-Dobson circulation, which moves more ozone from the tropics to the extratropics and enhances the tropospheric influx from the lowermost stratosphere. This climate feedback mechanism on tropospheric ozone is only partially compensated by the increasing chemical ozone loss associated to higher H2O values in response to the 40 tropospheric warming. We also note that ozone trends obtained in the lower stratosphere are negative (-2.2 percent/decade), but do not result to be statistically significant in our analyses.

Domains: Atmospheric and Oceanic Physics [physics.ao-ph]; Ocean, Atmosphere

Daniele Visioni, Giovanni Pitari, Vincenzo Rizi, Marco Iarlori, Irene Cionni, et al.. Seventeen years of ozone sounding at L'Aquila, Italy: evidence of mid-latitude stratospheric ozone recovery and tropospheric profile changes. 2020. ⟨insu-02886950⟩