EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Stratospheric OClO observed with ground-based DOAS over Kiruna in the Arctic winters 1996/1997 – 2019/2020

Myojeong Gu1, Carl-Fredrik Enell2, Janis Pukite1, Ulrich Platt3, Uwe Raffalski4, and Thomas Wagner1
Myojeong Gu et al.
  • 1Max-Planck Institute for Chemistry, Satellite Remote Sensing, Mainz, Germany (
  • 2EISCAT Scientific Association, Kiruna, Sweden
  • 3Institute for Environmental Physics, University of Heidelberg, Heidelberg, Germany
  • 4Swedish Institute of Space Physics, Kiruna, Sweden

Recent research on stratospheric ozone indicates signs of ozone recovery, but on the other hand, ozone recovery is also expected to be delayed by many aspects (e.g climate change). Therefore, it is important to monitor continuously stratospheric trace gases to predict the future evolution of the Arctic ozone and other trace gases which are involved in the ozone depletion chemistry. OClO is well known as an indicator of the stratospheric chlorine activation and can be measured using remote sensing techniques.

In this study, we present long-term measurements of OClO slant column densities at Kiruna, Sweden (67.84°N, 20.41°E) which were obtained from the ground-based zenith sky DOAS instruments since 1997. The measurement site is located north of the polar circle in which the variability of the OClO abundance depends on the state of stratospheric chlorine activation but also whether the polar vortex is located above the measurement site.

The aim of this study is to give an overview of the measured stratospheric OClO abundance for 19 years, and to investigate the dominant parameters affecting ozone and OClO during periods of stratospheric chlorine activation. One particular focus is on the parameters which trigger the activation and de-activation at the beginning and the end of the polar winter.

To do so, we compare the general dependencies of OClO on other trace gases and meteorological conditions.

How to cite: Gu, M., Enell, C.-F., Pukite, J., Platt, U., Raffalski, U., and Wagner, T.: Stratospheric OClO observed with ground-based DOAS over Kiruna in the Arctic winters 1996/1997 – 2019/2020, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8987,, 2021.

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