Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
doi:10.5194/acp-2017-327
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
18 Apr 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Trends and annual cycles in soundings of Arctic tropospheric ozone
Bo Christiansen1, Nis Jepsen1, Rigel Kivi2, Georg Hansen3, Niels Larsen1, and Ulrik S. Korsholm1 1Danish Meteorological Institute, Copenhagen, Denmark
2Finnish Meteorological Institute, Helsinki, Finland
3Norwegian Institute for Air Research, Fram Centre, Tromsø, Norway
Abstract. Ozone soundings from 9 Nordic stations have been homogenized and interpolated to standard pressure levels. The different stations have very different data coverage; the longest period with data is from the end of the 1980ies to 2014.

At each pressure level the homogenized ozone time-series have been analyzed with a model which includes both low-frequency variability in form of a polynomial, an annual cycle with harmonics, the possibility for low-frequency variability in the annual amplitude and phasing, and either white noise or noise given by a first order autoregressive process. The fitting of the parameters is performed with a Bayesian approach not only giving the mean values but also confidence intervals.

The results show that all stations agree on a well-defined annual cycle in the free troposphere with a relatively confined maximum in the early summer. Regarding the low-frequency variability it is found that Scoresbysund, Ny Aalesund, Sodankylae, Eureka, and Orland show similar, significant signals with a maximum near 2005 followed by a decrease. This change is characteristic for all pressure levels in the free troposphere. A significant change in the annual cycle was found for Ny Aalesund, Scoresbysund and Sodankylae. The changes at these stations are in agreement with the interpretation that the early summer maximum is appearing earlier in the year.

The results are shown to be robust to the different settings of the model parameters such as the order of the polynomial, number of harmonics in the annual cycle, and the type of noise.


Citation: Christiansen, B., Jepsen, N., Kivi, R., Hansen, G., Larsen, N., and Korsholm, U. S.: Trends and annual cycles in soundings of Arctic tropospheric ozone, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-327, in review, 2017.
Bo Christiansen et al.
Bo Christiansen et al.
Bo Christiansen et al.

Viewed

Total article views: 178 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
128 46 4 178 0 3

Views and downloads (calculated since 18 Apr 2017)

Cumulative views and downloads (calculated since 18 Apr 2017)

Viewed (geographical distribution)

Total article views: 178 (including HTML, PDF, and XML)

Thereof 177 with geography defined and 1 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 28 Apr 2017
Publications Copernicus
Download
Short summary
Ozone soundings in the troposphere from 9 Arctic stations covering the period 1984–2014 have been analyzed. Stations with best data coverage show a consistent and significant temporal variation with a maximum near 2005 followed by a decrease. Some significant changes are found in the annual cycle in agreement with the notion that the ozone summer maximum is appearing earlier in the year. Such changes in Arctic ozone in the free troposphere have not been reported before.
Ozone soundings in the troposphere from 9 Arctic stations covering the period 1984–2014 have...
Share