On the effect of large-scale atmospheric transport on chemistry and amount of atmospheric precipitation in the center of European Russia

The dependence of precipitation amount, acidity, and ionic composition on the atmospheric circulation is studied based on the computation of the back trajectories over the period of 1982–1993. Quantitative estimates of basic parameters of trajectories are derived, and their significant difference in the summer and wintertime is considered. The trajectory frequency for the cases with precipitation in the center of European Russia is computed at the regular grid points depending on the diurnal precipitation amount, acidity, and sulfate/chloride ratio. It is shown that in case of abundant precipitation both in summer and winter the highest frequency of trajectories is observed in the same regions. In the case of low precipitation, seasonal differences are observed. It is revealed that precipitation with pH > 5 is mostly connected with the air inflow from Scandinavia and the north of European Russia, while during the trajectory passage over Central and Southern Europe pH < 5 prevails in precipitation. The chlorine ions prevail most often when trajectories pass over central regions of the Mediterranean and of Middle Asia and (although somewhat less) over Scandinavia and northern Russian seas.