4.3 Snow cover
Snow measurements were conducted at the meteorological site of the
Suntar-Khayata Station at the altitude of 2070 m. The triangle plot with
the sides of 12 m was instrumented with three rails installed in the
corners where snow height and volume weight were measured each 10 days
(Koreisha, 1963). The snow data are available for only two years
(1958-1959).
At the altitude of the Suntar-Khayata Station, snow cover is formed in
early September and melts only in the second part of June – early July.
The snow-free period lasts about 2 months, (on average 56 days in
1957-1959).
Snow water equivalent (SWE) varies greatly from year to year. Maximum
observed SWE reached 348 mm in 1958 and only 153 mm in 1959. Maximum
simulated SWE amounted to 363 mm in 1958 and 171 mm in 1959. Mean
simulated SWE by the end of winter for the period of 1957-1964 was 251
mm.
The mean deviation value between simulated and observed daily SWE is
18.4 mm. The maximum deviation value reached 43 mm on November 20th,
1958. The absolute error of simulated maximum SWE is 5-12% during
1958-1959. Mean simulated SWE by the end of winter for the period of
1966-2012 was 213 mm and ranges from 114 mm (1983) to 379 (1967). The
height of snow changed from 44 cm to 99 cm and the mean value was 70 cm.
The comparison of simulated and observed values of SWE during winter
seasons 1958-1959 is presented in Fig. 4 and shows general model
adequacy. It is noteworthy that modelling results show that the snow
cover formed within 5 days from 5 to 10 August 1957 and then melted
(Fig. 4). The modelling results of the same state variable at the
Canadian Rocky Mountains watersheds shows that overestimation or
underestimation of the peak SWE ranged from 2.4 to 16% for the upper
watershed landscapes (Fang et al., 2013).
Snow surveys were conducted at the territory adjacent to the
Suntar-Khayata Station along a 3-km long route with elevation range over
400 m (2068 m – 2477 m) in 1957-1959. Spatial variation coefficient of
snow redistribution was calculated based on the data as 0.60. A normal
distribution (Vinogradov et al. 2011) was used to statistically account
for snow redistribution in the goltsy landscape based on this
estimation. In general, this value is consistent with the data on snow
variation for mountainous landscapes in the Yukon River Basin (SWE
variation is 0.69 by McCartney et al. (2006), 0.48 by Pomeroy et al.
(2004) and 0.69-0.84 in the upstream area of Kolyma River based on the
data by Makarieva et al. (2018a).