Trends in laminae in ozone profiles in relation to trends in some other middle atmospheric parameters

Ozone profiles measured by ozonesondes often do not display a smooth shape, they exhibit relatively narrow layers of significantly enhanced or depressed ozone concentration, called positive and negative laminae, respectively. At northern middle latitudes, the overall ozone content in laminae per profile reveals a strong negative trend since the late 1960s till the early 1990s. The trend changes to a pronounced positive trend around the mid-1990s. The trend in total ozone at northern middle latitudes changes as that in laminae in the mid-1990s from negative to positive. This change of trend is more probably of dynamical than chemical origin. Zonal winds in the upper middle atmosphere near 52°N reveal a change of trend in the 1990s, as well. This indicates possibility that the overall Northern Hemisphere middle atmosphere dynamics could experience a change in long-term trends in the 1990s.