Das Projekt "Ozone soundings as a tool for detecting ozone change" wird vom Umweltbundesamt gefördert und von Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Institut AWI - Forschungsstelle Potsdam durchgeführt. Objective: 1. To measure the rate and extent of ozone loss both inside the Arctic vortex and at middle latitudes during the winters of 1995-96, 96-97 and 97-98. 2. To follow the ozone destruction as it develops during an individual winter and from one winter to the next. 3. To investigate the structure and duration of laminae episodes. 4. To extend the important record of ozonesonde data obtained during the last four winters. 5. To build a data base of quality controlled ozonesonde data collected since 1988. 6. To provide this and other projects with meteorological analyses and forecasts from ECMWF. General Information: The work programme consists of five work packages: 1. Purchase and distribution of sondes and sonde operation 2. Match campaign and analysis If ozone loss occurs it will be detected by launching sondes from different stations into the same air mass a few days apart. This is achieved by using forecast trajectories. A large number of such matching pairs is needed in order to get a good statistics. It is the aim to investigate the ozone loss both inside the polar vortex and at middle latitudes. Sondes launched in Canada will be used as primary sondes, and the same air mass will be measured by the European stations. 3. Ozone laminae, climatology and trends 3.1 Mean ozone field 3.2 Ozone versus potential vorticity (PV) The effects of dynamics will be isolated from chemical effects by considering the relative evolution of ozone and PV. 3.3 Extension to subtropical latitudes This activity will address changes in the ozone distribution caused by dynamical changes, which can then be linked to the effects seen at middle latitudes. 3.4 Ozone trends on isentropic levels The temporal evolution of the ozone mixing ratio at isentropic surfaces will be studied. Diabatic descent will be accounted for. Data will be sorted according to the PV values at the sounding site. 3.5 Measurement of ozone laminae A newly improved ozone lidar will measure ozone from 4 to 18 km. It will be used to measure the passage of ozone laminae over Aberystwyth, in order to determine the typical along-flow scales of these features. 4. Quality control and homogeneous ozonesonde data base Ozonesonde data will be subject to daily quality control. A comparison of how the different stations convert raw data to geophysical data will be carried out before winter 1996-97. Common sounding instructions will be distributed to the stations. After the campaign the post mission quality control will verify the correctness of the final data in close collaboration with the station PIs. An archive of quality controlled data from 1988-1998 will be made and disseminated on CD-ROM. 5. Data centre and ECMWF data Ozonesonde data will be collected from the sounding stations in near real time. Data from ECMWF will be collected for use by OSDOC and some other projects. Prime Contractor: Norwegian Institute for Air Research; Kjeller; Norway.