Speaker
Prof.
Christos Zerefos
(Academy of Athens)
Description
This study analyses vertical ozone trends from lidar measurements, ozone sondes and SBUV/2 satellite overpasses at Hohenpeissenberg, Haute Provence, Table Mountain, Mauna Loa and Lauder for the period 1998 to 2016. The analysis focuses on stratospheric, tropospheric and total ozone using observed and modelled ozone. Measurements are compared with chemical transport model simulations from the Oslo CTM3 model, which has been used to investigate the effect of chemical related processes on the observed ozone trends.
To understand the role of chemistry on stratospheric ozone trends we present model runs from the full chemistry model in comparison to fixed halogen emissions at 1998 levels. Comparison between the fixed and full chemistry halogen emissions shows that the reduction of halogen emissions explains about 35% of the observed upward trend in the upper stratospheric ozone (1-7 hPa) and about 10% in the lower stratospheric ozone (30-100 hPa).
After the year 1997, both measurements and model data agree well and show that the vertical structure of ozone trends can be characterized by four main features: an increase in ozone in the upper stratosphere above 7 hPa, no trend in the middle stratosphere between 7 and 30 hPa, a decrease in the lower stratosphere between 30 and 100 hPa, and an increase in tropospheric ozone amounts. This interchange of positive and negative trends in the vertical ozone profile resulted to observed insignificant trends in the total ozone column in the past 2 decades.
Primary author
Dr
John Kapsomenakis
(Academy Of Athens)
Co-authors
Dr
Amund Haslerud Sovde
(CICERO, Norway)
Prof.
Christos Zerefos
(Academy of Athens)
Dr
Kostas Eleftheratos
(University of Athens)
Mrs
Stacey Frith
(SSAI)
Dr
irina Petropavlovskikh
(NOAA/CIRES)
