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Third European Stratospheric Experiment on Ozone - Ozone Loss in the Arctic and at Mid-Latitudes


The objectives of THESEO-O3 LOSS are:
1). To quantify precisely the rate of chemically-induced ozone loss as a function of time both inside the Arctic vortex and at middle latitudes during two consecutive years. The cumulative chemical ozone loss and its geographical extent will also be determined.
2). To obtain a better agreement between measured ozone loss and ozone loss as calculated by 3-D chemical transport models and thereby improve their predicitive capability. This will also help to identify and quantify the causes of ozone reduction inside and outside the polar vortex.
To meet these objectives we propose to carry out the following two work packages:
1. Chemically-induced ozone loss rates will be measured directly through a sophisticated real time ozonesonde launch programme where two sondes probe the same air mass a few days apart. This will be achieved through the use of forecast trajectories. Vertical diabetic motion will be accounted for, both in the real-time forecast trajectories and in the analysis of the ozonesonde data. Results from a photochemical modelling activity utilising the trajectories used for analysis of the sonde data will be compared to the experimental ozone change and a sensitivity study will be carried out and the results communicated to 3-D modelling groups in a collaborating proposal.
2. The picture of the ozone loss will be completed through a combination of balloon measurements and analysis of various data sets produced by other projects. The results of comparison with 3-D model calculations will be fed back to the modelling groups. Lightweight instruments will be used to measure vertical profiles of ozone and passive tracers (CFCs and methane) simultaneously, whereby the effects from diabetic heating/cooling can be eliminated.
This proposal builds on the work in SESAME and represents a step forward because
1). It allows for a more precise determination of the chemical component of the ozone change through the concurrent measurement of ozone and tracers,
2). The degree of ozone loss will be determined simultaneously by two independent techniques, namely the Lagrangian ozonesonde study and by comparison between ozone measurements and 3-D modelling,
3). The 3-D CTMs' capabilities to describe diabetic processes and ozone change will be verified against vertical profile measurements of ozone and tracers
4). Coordinated ozonesonde launches will be used to measure directly the ozone loss, not only inside the vortex, but also along the vortex edge, in air parcels leaving the vortex and in-situ at mid-latitudes.
THESEO-03 LOSS has a clear European dimension as it brings together research groups from many countries including less favoured regions and Eastern European countries and because the proposed work could not have been carried out by one nation alone.
The results from THESEO-O3LOSS will be published in peer reviewed papers, presented at conferences and made available to a larger audience through the World Wide Web. Data will be disseminated on CD-ROM. This is in accordance with the partners' commitment to dissemination of data and results as shown through cooperation in earlier projects.
The project contributes to the formulation of the Union's environmental policies through increased insight in the relations between halogen concentrations and stratospheric ozone change in Europe and neighbouring regions.

Funding Scheme

CSC - Cost-sharing contracts


Instituttveien 18
2027 Kjeller

Participants (2)

Central Aerological Observatory
3,Pervomayskaya Street 3
141700 Moskva
Institute of Meteorological and WaterManagement
38,Zegrzynska 38
05 119 Legionowo