Analysis of laminated structure in ozone vertical profiles in central Europe

Using statistical techniques, we study therelationship between the long-term changes in the laminar structure of the ozonevertical profile at two central-European stations - Hohenpeissenberg andLindenberg - and other quantities potentially affecting the state of the lowerstratosphere, and total-ozone content. We consider only positive laminae greaterthan 30 nbar. Laminae contribute non-negligibly to total ozone, and thiscontribution varies strongly with season. The maximum laminae-occurrencefrequency in late winter/early spring is five-times higher than the minimum inearly autumn. The main result of the paper is the discovery of a strong negativetrend in the frequency of laminae occurrence, about –15% per decade, and even aslightly stronger negative trend in ozone content in laminae. Strong negativetrends in laminae occurrence imply negative changes in total ozone as well. Nopronounced effect of the quasi-biennial oscillation and solar cycle on laminaewas found, whereas the 100-hPa temperature had a clear effect, and there was anindication of substantial effects of volcanic eruptions and El Niño southernoscillation events. Long-term changes in individual time series ofmeteorological parameters measured over Hohenpeissenberg do not indicate theirsignificant role in the observed trend in laminae occurrence. On the other hand,there is some increase in the occurrence of very zonal circulation patterns, aswell as slight decrease in very meridional circulation patterns. Together withother indications this allows us to say that dynamical effects are expected tobe a principal contributor. Thus changes in laminae occurrence will probably beable to serve as an indicator/tracer of long-term changes in lower-stratosphericdynamics