ZONAL DISTRIBUTIONS OF NITROGEN-OXIDES FROM SURFACE SOURCES IN THE MIDLATITUDE TROPOSPHERE OF THE NORTHERN-HEMISPHERE

The influence of a nonuniform intensity of surface NOx sources on the distribution of gases in the midlatitude troposphere of the Northern H emisphere is studied. A nonstationary two-dimensional model taking int o account photochemical conversions and height-longitude transport of pollutants in the latitudinal zone 30-60 degrees N was used, From publ ished data on the location of surface NOx sources over Eurasia and Nor th America, height-longitude distributions of nitrogen compounds and o zone are studied. It is found that there are regions of increased and reduced contents of these compounds and ozone in the middle and upper troposphere over the Pacific Ocean and over the North America and the Atlantic Ocean, respectively. Such regions are mainly associated with dynamic processes and with an abrupt change in the intensity of surfac e sources from maximum values on the continent to minimum values in th e ocean. The nonuniformity of the NOx source field is most significant in the lower troposphere. It is shown that the localization of anthro pogenic NOx sources in the coastal regions of continents has an effect on the distributions of nitrogen compounds, ozone, and other trace ga ses in the middle and upper troposphere.