The European Arctic Stratospheric Ozone Experiment is a European Commission (EC) measurement campaign undertaken in the Northern Hemisphere winter of 1991-92 to study ozone chemistry and dynamics. The dataset contains measurements of chemical constituents (concentrations of ozone and the members of the chlorine and nitrogen families) and meteorological parameters from European ground stations and balloon and aircraft flights, and from the ground-based ozone monitoring network. This dataset is public.

This dataset was produced using a Nd-YAG laser, 0.6m diameter mirror, two receiver channels - one for parallel and the other for perpendicular polarisation. Photon counting system; raw data collected at 30m resolution (both channels simultaneously). Each individual measurement takes 5 minutes (5000 shots). For the data here, all measurements for an individual evening have been combined. Usually, 2 or 3 consecutive runs were made, but on some evenings (e.g. December 6-9 1991) a large number of profiles were measured. Times of measurements are not given here but can be supplied on request; each was made within 4 hours of 2000 GMT and during hours of darkness. Detailed data for each run are also available on request.

To derive backscatter ratios, atmospheric density profiles were derived from ozonesondes launched from Aberystwyth during EASOE. These were corrected for air and ozone absorption. The top of the aerosol layer for each night was determined by inspection of the counts*height squared (Ch2) profile, and the average ratio of Ch2 to corrected density above this height was used to derive the backscatter ratio.

Correction for aerosol absorption was made using an extinction/backscatter ratio of 40, assumed constant throughout the layer.

For depolarisation ratio, the ratio of the two receiver channels is shown, corrected for the beamsplitter efficiency. Also, all the data have been normalised so that the lidar depolarisation ratio for air (above the aerosol layer) is 1.4%. (Note: this is different from the preliminary data).

Data are shown above 10 km, except where cirrus was present, when the altitudes contaminated by cirrus have been removed. Below 10 km, the count-rates were too high for the recorded data to be reliable. The upper height reported is that of the top of the aerosol layer.