17-19 September 2018
WMO, Geneva
Europe/Paris timezone

LOTUS is an international research initiative endorsed by SPARCIO3C and WMO (GAW) that kicked off at the Quadrennial Ozone Symposium in 2016. LOTUS focuses on revisiting the estimates and understanding of Long-term Ozone Trends and Uncertainties in the Stratosphere, in support of the WMO/UNEP 2018 Ozone Assessment. The LOTUS report was accepted for publication in May 2018, completing the main objective of the first phase of the activity. More detailed information on LOTUS can be found at our main website.

LOTUS will hold its second workshop from Mon 17 Sep (10:30) to Wed 19 Sep (12:30) in Geneva, Switzerland. This invite-only workshop will be informal with selected scheduled oral presentations and with ample time for discussions in large or small groups.

Main objectives

  • Recap of the main results of the first phase of LOTUS and the WMO/UNEP 2018 ozone assessment.
  • News, revisions, and updates of satellite, ground-based and model ozone data records.
  • Reconsideration of the regression model and trend estimates for lower stratospheric ozone (satellite & ground-based measurement).
  • Link between ozone profile trends and total column trends.
  • Discussion of methods to combine trend results.
  • Attribution of profile trends using model data.

We gratefully acknowledge the support by



Group picture


WMO, Geneva
Salle B
Avenue de la Paix 7bis, Geneva, Switzerland
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