LONG-TERM CHANGES IN THE SNOW COVER REGIME ACCORDING TO DATA OF THE NALCHIK WEATHER STATION

Abstract

The study aims to analyze long-term changes in the average ten-day thickness of snow cover at theNalchik weather station (Kabardino-Balkarian Republic) during the cold season (October-April) for the period from 1960/1961 to 2017/2018 and to make a forecast until 2037/2038. The paper presents the results obtained by processingdata series from the station using STATISTICA 10.0 and SPSS 21.0 statistical packages.The average ten-day thickness of snow cover was found to be 3.95 cm, with a norm of 3.8 cm (1961-1990); therange between the minimum and maximum values for the period 1961-2018 is quite large R=14 cm. Using the quantilemethod, 3 extreme values were determined – 10 cm (1992/93), 11 cm (1973/74), and 15 cm (2011/12).Studies of the periodic components of snow cover thickness, carried out using STATISTICA 10.0 statistical package and the method of singular spectrum analysis, have shown that the maximum peaks fall within periods T1 ≈ 10 years,T2 ≈ 19 years, and T3 ≈ 5 years.Graphs were constructed showing variations in the averaged values ten-day thickness of snow cover from the 1stto the 21st decade of the cold season of 1961-2018, from which it is clear that the maximum snow cover thickness (h = 6 cm )from the long-term average values was determined for the 14th decade of the cold season (2nd decade of February).According to the forecast of the average ten-day snow thickness until 2038, carried out using singular spectrumanalysis, periods of decreasing snow cover thickness are expected from 2023 to 2025 and from 2030 to 2034, and periodsof increasing thickness – from 2025 to 2030 and from 2035 to 2038.