Measurement of the latitudinal distribution of NO 2 column density and layer height in Oct. / Nov. 1993

In October/November 1993 DOAS measurements of total columns of NO 2 and O 3 were performed on a ship cruise from Germany to South Africa. The results are compared to data collected during an earlier campaign with a similar setup [ Kreher et al . 1995], which took place in 1990, before the eruption of the Pinatubo volcano. Overall no general trend for NO 2 in 1993 in comparison to 1990 could be detected. The O 3 vertical column densities in 1993 are mostly around 280 Dobson Units, showing a significant increase to over 330 DU south of 25°S, and significantly lower O 3 values south of 50°S. The height of the NO 2 concentration maximum was calculated from the NO 2 am/pm ratio and data from ozonesondes. The resulting heights are mostly round 29 km, except in the region (south of ≈ 45°S) where the lowest ozone column densities occurred, there the calculated height is ≈ 22 km.