RECONSTRUCTION OF CHANGES IN STRATOSPHERIC OZONE IN THE TAIGA FORESTS BASED OF THE SINGULAR SPECTRAL ANALYSIS

Abstract

The relevance. The problem of reducing the level of stratospheric ozone and the interest in its past changes are associated with the increase in the dose of ultraviolet radiation in the short-wave range reaching the Earth's surface. Reconstruction and prediction of long-period fluctuations of the studied parameters can be carried out using the method of multiple regression according to the density of annual growth rings of conifers. In order to expand the experimental data base, exploratory work is being carried out to measure new characteristics of annual growth rings, as well as the mathematical apparatus of data preprocessing techniques is being refined, the connections of bioindicators with atmospheric parameters are being analyzed and new models of their prediction are being developed. Reconstruction of historical changes in atmospheric characteristics can be considered in the context of the prospect of artificial restoration of forest resources. The aim of the research is to discuss a technique for reconstructing the total ozone content based on a multicomponent singular spectral model of the response of conifers annual growth rings. Objects. During the growing season, trees form a woody structure of annual growth rings with the properties of a composite material. Each of the components of the annual growth rings such as a carbon-containing matrix, water and carbon dioxide contains responses to changes in environmental conditions. On the basis of a multicomponent model, the total responses of annual rings obtained using the Caterpillar SSA 3.40 software can be used to reconstruct changes in the total ozone content in zones with optimal coniferous growth conditions, as opposed to zones with dominance of the temperature factor. Methods: dendrochronological method; singular spectral analysis; econometric methods of time series analysis; data mining; simulation modeling. Results. The reliability of the model of responses of coniferous annual growth rings to changes in atmospheric parameters is confirmed by a sample of ergodic chronologies of wood components. The Durbin–Watson statistic makes it possible to identify a group of chronologies in whose models there is no autocorrelation of perturbations. The use of the cumulative response model for three wood components significantly increases the reliability of the reconstruction of the studied atmospheric parameters for the taiga zone with optimal conditions for annual tree growth. The data of the reconstruction of the total ozone content for the taiga zone of the Tomsk region allow us to conclude that despite the increase in the ozone level in the stratosphere, the changes in the total ozone content have not returned to their average historical values, the level of UV-B is still high, but nevertheless the territory and the modern period are favorable for forest plantations.

Keywords

• ultraviolet b radiation
• air temperature
• amount of precipitation
• wood density
• annual rings