Varduhi G. Margaryan. LONG-TERM FLUCTUATIONS IN THE ANNUAL RUNOFF OF RIVERS FLOWING INTO LAKE SEVAN UNDER THE CURRENT CLIMATE CHANGE

https://doi.org/10.15407/ugz2021.04.030
Ukr. geogr. z. 2021, N4:30-38
Authors: 

Varduhi G. Margaryan - Yerevan State University, Yerevan, The Republic of Armenia.

Abstract: 

The work identified, analyzed and assessed long-term fluctuations annual runoff of rivers fl owing into Lake Sevan. As a starting point material used daily data of long-term actual instrumental observations of the annual runoff of rivers fl owing into the lake, and also the air temperature and precipitation of the lake basin for the entire observation period (1927–2018). Analysis of the trend lines shows that in the lower river sections of the observed rivers (except for the rivers Vardenis and Bakhtak) are mainly observed the tendency of growth of average annual values of water consumption Such the pattern is also inherent in temporary changes in average annual temperatures and annual precipitation of the study area. It turned out that in the study area for the entire period of instrumental observations, the average annual air temperature increased by 0.5–1.5 ° C or 10–30%, and precipitation increased by 80–150 mm or 15-40%. Changes in river runoff reflect changes in precipitation. The values of the coefficient of variation (variability) of the river runoff of the studied territories vary widely - from 0.13–0.23 (rivers with underground feeding) to 0.30–0.40 (rivers with surface feeding), which due to different regimes of feeding the rivers of the basin, and the values of the coefficient asymmetry – in the range from –0.85–0.93. The paper discusses the issues of changing the cyclicity and synchronicity of the river drainage of the lake basin. It turned out that the change in runoff is characterized by cyclicity, and the synchronous change in the runoff is not clear.

Key words: 
river runoff, air temperature, precipitation, trend, cyclicality, synchronicity, Lake Sevan basin
Pages: 
30-38
References: 

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