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Summary & Executive Research Plan |
SUMMARY | EXECUTIVE RESEARCH PLAN
Summary
Human activities, the emission of ozone depleting gases such as chlorofluorocarbons (CFCs), halons and other, can lead to the destruction of stratospheric ozone. The speed of destruction is faster at lower temperatures. The coldest temperatures occur over the Arctic and Antarctic, and the largest ozone losses have been observed there.
The main public concern from reduced ozone is the increased amount of ultraviolet radiation at the earth's surface, which can harm many forms of life, including skin cancers and eye damage.
The European response
THESEO, the Third European Stratospheric Experiment on Ozone, is taking place during 1998 and 1999. The main aim is to improve our understanding of the causes of ozone depletion over Europe and other mid-latitude regions, where the ozone layer has been progressively depleted for the last 20-30 years. A quantitative understanding of the causes is necessary to support any future political, within the Montreal Protocol.
THESEO is a wide-ranging field programme throughout the northern hemisphere. Measurements being made by instruments on satellites, balloons, aircraft and the ground. It involves more than 400 scientists from over 20 countries. THESEO was preceded by the European Arctic Stratospheric Ozone Experiment (EASOE) in 1991/92 and the Second European Stratospheric Arctic and Mid-Latitude Experiment (SESAME) in 1994/95.
THESEO consists of a core of 12 major projects funded by the European Union within the Environment and Climate Programme:
| Airborne Platform for Earth observation: the contribution to THESEO (APE-THESEO) L. Stefanutti, IROE-CNR, Italy |
| Concerted Action for Scientific Strategy In the Stratosphere (CASSIS) J. Pyle, Coordinating Unit, United-Kingdom |
| Mid and high latitude stratospheric distribution of long and short lived HALOgen species during the MAXimum chlorine loading (HALOMAX) A. Engel, University of Frankfurt, Germany |
| HIgh and Middle latitude SPECiation of the nitrogen chlorine and hydrogen chemical families by airborne measurements (HIMSPEC) H. Oelhaf, FZK-IMK, Germany |
| A lagrangian experiment in Arctic vortex (LAGRANGIAN) J.P. Pommereau, SA/CNRS, France |
| MEridional TRansport of Ozone in the lower stratosphere (METRO) A. Hauchecorne, SA/CNRS, France |
| In-situ analysis of aerosols and gases in the polar stratosphere: a contribution to the THESEO campaign (PSC) N. Larsen, DMI, Denmark |
| Third European stratospheric experiment on Stratospheric Ozone Destruction by Bromine (STRATOSPHERIC BrO) M.Van Roozendael, IASB, Belgium |
| Stratosphere - TRoposphere Experiments by Aircraft Measurements III (STREAM-III) J. Lelieveld, IMAU,The Netherlands |
| THird European Stratospheric Experiment on Ozone - Ozone Loss in the Arctic and at Mid-Latitudes (THESEO-O3 LOSS) G. Braathen, NILU, Norway |
| TOwards the Prediction of stratospheric Ozone (TOPOZ-2) W. Norton, University of Oxford, United-Kingdom |
| TRAnsport of Chemical species Across the Subtropical tropopause (TRACAS) G. Ancellet, SA/CNRS, France |
| Water vapour measurements from the tropics to the pole during the THESEO campaign 1998-1999 (WAVE) J. de La Noë, University of Bordeaux, France |
The research funded by the European Union in THESEO is closely coordinated with, and substantially increased by, the national research programmes.
For further information, please contact:
Dr Georgios Amanatidis
Scientific Officer, Environment and Climate, DG XII-D
Fax: + 32-2-296.30.24
E-mail: georgios.amanatidis@ec.europa.eu
Dr Neil Harris
European Ozone Research Coordinating Unit
Fax: + 44-1223-31.17.50
E-mail: general@ozone-sec.ch.cam.ac.uk
THESEO Executive Research Plan
The primary goal of THESEO is to improve our understanding of the processes underlying the observed mid-latitude ozone trends. This can only be achieved through a better understanding of the chemical and dynamical links with other regions, i.e. with the lower stratosphere in both the subtropics and in the Arctic, and with the upper troposphere and upper stratosphere at mid-latitudes. This aim is an ambitious one - the processes occurring at mid-latitude are more complex and variable than in the vortex - and any perturbations to the ozone amount or the chemical composition are likely to be smaller than in the polar vortices. In addition, a number of critical questions about the processes occurring inside the vortex remain unanswered, not least the reasons why models continue to calculate less ozone loss than is observed.
Measurements will be made at locations from the tropics to the Arctic. A balloon campaign involving 15 large balloons will take place in Kiruna in January and February 1999. A number of long duration balloon flights will be made to provide continuous, quasi-Lagrangian measurements of species such as O3, and CH4 for periods of several weeks. The large balloon activities will be linked to the ozonesonde and small balloon programmes which will measure the ozone loss inside the polar vortex. The main focus of the ozonesonde effort will be directed toward determining mid-latitude ozone loss rates. It is planned to make greater use of the lidar network to increase the number of available measurements. This will be complemented by chemical measurements made from the large balloons and from the ground-based network.
A number of aspects of the large-scale circulation will be investigated. The flux into the tropical stratosphere will be involving the aircrafts M-55 Geophysika and the DLR Falcon. They will fly over the Indian Ocean in early 1999. In the Arctic a series of tracer measurements will be used to infer the diabatic descent rate, and to study the mixing processes. The linkages of these two regions with the mid-latitudes will be studied through a combination of ground-based and aircraft measurements and models. Aircraft will also be used to investigate the complex processes occurring in the lower stratosphere and upper troposphere.
State-of-the-art 3-D chemical transport models developed in recent years will be during the campaign. A great number of measurements will be made that particularly focus on issues relating to transport and dynamics, and detailed modelling studies of these data will be needed in conjunction with similar analyses from earlier years. It is hoped that the measurement strategy can be guided by the models. Full use will be made of the data collected by European satellite instruments (GOME since 1995, POAM-3 and future launches of ODIN, ENVISAT).
THESEO | Joint Actions - Environment & Climate / MAST | 17.02.2000
