Dendroindication of Lake Baikal level dynamics

Abstract

This paper estimates and analyzes water level dynamics in Lake Baikal in the 15th-20th centuries by a method of dendroindication. The endrochronological material for the study was obtained in the Zabaikalsky National Park in 2007. Apart from the chronologies of 2007, the available temporal data sequence is extended by incorporating tree-ring chronologies collected in the 1950s by G. I. Galasy and published in a digest on "Dendrochronological Scales of Soviet Union". The largest coefficients of positive correlation are found to be between the PinSib10 sample and the cumulative monthly precipitation of February and October and also between the PinSib2 sample and the precipitation of November and the cold season (November-March). A tighter relation between the annual ring increments and the lake level existed before the construction of the hydropower station in the city of Irkutsk. After the construction the increments have also been rather sensitive to changes in the level. The significant correlation between the increment variability and the Lake Baikal level allows the development of a quantitative model of reconstruction of the lake level. The model reproduces up to 60% of the known level variations. The reconstruction shows high level epochs as well as durable epochs of low level. A spectral Fourier analysis reveals cycles of 53, 33, 23, 17, and 11 years in the reconstructed series of the Lake Baikal water level.