Variations of Total Nitrogen Oxide Content in the Atmosphere over the North Caucasus

Abstract

The data are presented on total nitrogen dioxide (NO₂) content in the atmosphere from 1979 to 2009 at the high-mountain scientific station located in the unpolluted area in the North Caucasus at the height of 2070 m above the sea level (43.7° N, 42.7° E). The total content of NO₂ was measured on the basis of attenuation of direct solar radiation over slope pathways after the sunrise and before the sunset. Characteristics features are analyzed of temporal variability of total NO₂ content in the atmosphere related to its diurnal and seasonal variations, 11-year solar activity, volcanic eruptions, quasi-biennial oscillations of tropical circulation, and the El Niño effect.