Assessment of the contributions of dynamic and chemical factors to variations in the total ozone content in the extratropical latitudes of the Northern Hemisphere

On the basis of the data obtained at 167 ozonometric stations of a ground-based network for the extratropical latitudes of the Northern Hemisphere, the fields of the total ozone content (TOC) trends are plotted for each month from November to March. With the use of TOC regression fields with respect to the geopotential H in the circumpolar-cyclone center at a level of 30 hPa, the fields of TOC trends resulting from H trends arc calculated. The differences between these trends are treated as the fields of trends of chemical origin plus regional trends of dynamic origin. The relation between the trends of dynamic and chemical origins strongly depends on region and season. The integral value of the TOC for the extratropical latitudes of the Northern Hemisphere is characterized by the comparability of the contributions made by the trends of both dynamic and chemical origins to the general negative trend of the TOC.