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Conclusions 
		
		 Between 460K and 560K: in the 1990s ozone values in winter are
		smaller than expected by the fit to 1980s' values and can not
		be explained dynamically in terms of varying origin.
 Between 340K and 440K: No trend in ozone at these altitudes. Variability can be dynamically explained by the changing frequencies of transport form polar vs. subtropical regions.