GROUNDBASED MEASUREMENTS OF STRATOSPHERIC OCLO, NO2, AND O3 AT SONDRE-STROMFJORD IN WINTER 1991 92/

Experiment (EASOE) campaign Within the scope of the 1991/92 European A rctic Stratospheric Ozone stratospheric chlorine dioxide, OClO, nitrog en dioxide, NO2, bromine monoxide, BrO, and ozone, O3, were measured b y groundbased UV-VIS remote sensing in Sondre Stromfjord, Greenland (5 0.4-degrees-W, 67.0-degrees-N). The measurement period was from the mi ddle of November 1991 until the end of January 1992. The anticipated c orrelation between potential vorticity and OClO appeared less pronounc ed in the beginning and its abundance was similar inside and outside o f the polar vortex. During November 1991 stratospheric temperatures th roughout the polar region were still above threshold for polar stratos pheric cloud (PSC) formation. During January when NO2 column densities were at their lowest, OClO inside of the vortex appeared to be highly variable. Average vertical column densities reached about 10(13) mole c cm2, less than found in previous years. The chemistry as well as the observations may have been disturbed by the aerosol cloud from Mt. Pi natubo eruption.