Dynamics of snow cover characteristics in landscapes of the Tom-Yaya interfluve

The snow cover plays an important role in the formation of weather, landscapes, as well as the social-economical life in countries of temperate and polar latitudes. Hence, the study of snow cover in conditions of the changing climate is the object of much attention. The statistical analysis of essential snow cover characteristics was carried out on the basis of the areal landscape-route snow survey performed in the microscale. Particular emphasis was placed on the snow cover thickness dynamics, density and moisture content for the period of 1988 to 2012. The object of the investigation was a district in the Tom-Yaya interfluve nearby the village of Luchanovo (20 km south-eastward of Tomsk) including different sites: namely, agricultural lands divided by tree belts, cedar and birch-aspen forests, tilled hollows. The following results are obtained: 1. At the time of the maximum snow accumulation, the snow cover thickness changes from zero values to 211 cm with the long-time average annual of 53 cm. The majority of winters during 25 years were medium snowy (60%). In the cedar forest the minimal snow thickness (27 cm) was observed in 2012 with the long-time average annual of 59 cm, and the maximal one in 1997 (72 cm). The significant difference in the snow cover thickness on field sites is connected with differences in the slopes exposure, microrelief, snow drift transport, vegetation, etc. 2. The density of snow cover in the cedar forest averages 0.21 g/cm , and on the cropland 0.26-0.1 g/cm , the coefficient of the snow cover density variation on all sites ranges from 0.07 to 0.11. 3. Moisture storages varied from 10 mm (1999) on the watershed of tilled hollows (southern slope) to 161 mm (2010) with the long-time average annual of 99 mm, while in the cedar forest from 51 mm (2012) to 156 mm (2007) with the long-time average annual of 123 mm. The variation coefficients of the moisture storage series on all sites range from 0.16 to 0.35. 4. The comparative analysis of the snow surveys data for the periods of 1935/36 -1969/70 and 1987/88 - 2011/12 demonstrated the increase in the average density of the snow cover on the field sites. This seems to be connected with the expansion of agricultural lands, the strengthened eolation, more frequent thaw periods in the conditions of the changing climate. The long-time average annual of moisture storages on the field sites are similar in values ((100-146 mm). The obtained results are of great scientific and practical importance for evaluating and forecasting the spring flood on mean and small rivers, for the analysis of the development of the soil water erosion, the calculation of solid discharge, the stability of landscapes functioning, because the snow cover plays an important role in the mechanism of their development.

Keywords

Authors

References