[M-IS01] ENVIRONMENTAL, SOCIO-ECONOMIC, AND CLIMATIC CHANGES IN NORTHERN EURASIA

[MIS01-P02] Long-term Changes in the Water Levels of Lake Baikal in the 20th–21st Centuries

*Georgiadi Aleksandr¹、Sinyukovich Valery²、Groisman Pavel³、Borodin Oleg⁴、Aslamov Ilya² (1.Institute of Geography, Russian Academy of Sciences、2.Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033 Irkutsk, Russia、3.North Carolina State University at NOAA National Center for Environmental Information and Hydrology Science & Services Corporation, Asheville, North Carolina, USA、4.Water Problems Institute, Russian Academy of Sciences, 119333 Moscow, Russia)

キーワード：Baikal、lake level changes、impact of the Irkutsk hydroelectric power plant、long-term trends

Based on multi-year data on the observed and naturalized levels of Lake Baikal, its main tributaries, and the Angara River, this study assessed the temporal patterns and degree of coupling of multi-year and intra-annual changes in the Lake’s monthly, seasonal, and annual characteristics. The estimation of the average monthly levels of Lake Baikal and the Angara water discharge after the construction of the Irkutsk hydroelectric power plant (HPP) was based on the relationship of the fluctuations with the components of the Lake water budget before regulation. As a result, a 123-year time series of "conditionally natural" levels of Lake Baikal and the Angara River discharge were reconstructed. The statistical characteristics, transition probabilities, and internal correlations of the time series were calculated. The results indicated high inertia in the fluctuations of the Lake level. Additionally, we found a century-long tendency towards seasonal increases in the Lake level of about 15 cm per 100 years and quantified the low-frequency changes in Baikal water levels and discharge of the Angara River and the main tributaries of the lake. Assessment of the impact of the Irkutsk HPP on the multi-year and intra-annual changes in the Baikal water level and Angara discharge showed that the restrictions on the discharge through the Irkutsk HPP and legislative limitations of the Baikal level regime have significantly limited the Lake level fluctuations.