Modeling the variability of the atmospheric gas composition at RSHU

Abstract

A set of numerical models of the lower and middle atmosphere gas composition has been created at the Russian State Hydrometeorological University (RSHU). The set of RSHU numerical models consists of a global chemistry-climate model (CCM) of the troposphere, stratosphere and mesosphere (0-90 km), a chemistry-transport model (CTM) of the troposphere and stratosphere gas composition with meteorological parameters specified from reanalysis data (0-60 km), and a model of Eurasia air quality (0-32 km). All models use a single block of chemical transformations in the atmosphere and different ways of using meteorological parameters that determine the effect of atmospheric transport on atmospheric gases. The CCM allows us to study the interaction of physical and chemical processes in the lower and middle atmosphere, the CTM is suitable for studying the influence of chemical processes on the gas composition of the atmosphere under a given influence of dynamic factors, and the air quality model can be used to analyze the impact of surface emissions of pollutants and meteorological conditions on the observed variability of air quality in different parts of Eurasia. Numerical experiments with RSHU CCM described in this article allowed us to identify the relative role of natural and anthropogenic factors in the interannual variability of atmospheric ozone in tropical, middle and polar latitudes. Quantitative estimates of ozone trends revealed a greater rate of ozone decrease in Northern mid-latitude compared to its variability in the tropical latitudes. During periods of sharp ozone decrease and then recovery in the 90th years of the twentieth century, in the tropics and mid-latitudes, the additive role played by the combination of several factors: the fall in ozone as a result of increased content of chlorine and bromine gases and reduction in solar activity and the role of sea surface temperature on the background of increasing chlorine and bromine gases and the increase in the ozone content in the result of the purification of stratospheric aerosol and the influence of the variability of sea surface temperature and growth of solar activity. The results of numerical calculations with CTM demonstrated the predominant role of dynamic processes in the formation of winter-spring ozone anomalies in the Arctic and Subarctic. Rapid use of the air quality model has shown the important impact of meteorological conditions on air quality in Eurasia