By launching several hundred ozonesondes and by ozone lidar measurements at many Arctic and sub-Arctic stations, one of them Ny-Ålesund, the stratospheric chemical ozone loss will be determined. The launches of all stations will be coordinated by analysis of trajectory calculations based on analysis and forecast wind fields. The aim is to get as many ozone sounding pairs as possible, each of them linked by trajectories in space and time. A statistical description of the ozone differencies given by the first and the second measurement of individual sonde pairs will yield the chemical ozone loss with spatial and time resolution. Four similar campaigns took place in the Arctic and in the mid-latitudes covering the time period of Januar to March in each of the last four winters. In the first three winters high ozone depletion rates (20 - 50 ppbv per day) were determined in some height levels within the polar vortex. In the height level of the ozone maximum an integrated ozone loss (during the winter) in the order of 60 % have been found. These are record ozone losses for the Arctic polar region. In the last winter the ozone depletion rates had been much lower due to moderate temperatures in the stratosphere.
Norwegian Institute for Air Research, Kjeller, (NILU) University of Cambridge FU-Berlin Finnish Meteorological Institute, Sodankylä (FMI) Serveral other institutions which launch ozonesondes at Arctic stations