During the first three months of 1993 measurements of the vertical ozone profile, with balloon-borne sensors, were performed in Greenland. A substantial ozone depletion took place from the end of January to the end of March in the altitude range between approximately 14 and 20 km. An ozone decrease of about 1% per day is ascribed to chemical destruction inside the polar vortex based on air parcel trajectory analysis, using measurements of lower stratospheric aerosols as dynamical tracers to correct for diabatic subsidence. The column-integrated total ozone loss was found to be about 48 Dobson units or 12%. These measurements are in good agreement with satellite observations, and further document the 1993 springtime stratospheric ozone depletion as the most severe and long lasting yet reported for the Arctic. ¿ American Geophysical Union 1994