Zhukova J., Osadcha L., Tsvetayeva O.

Oles Honchar Dnipropetrovsk National University

 THE SPATIAL VARIABILITY OF SNOW COVER AND SOIL SURFACE TEMPERATURE OF THE STEPPE

The snow cover is a layer of snow on the soil surface formed by snow. The thickness of the snow cover and it’s mechanical properties vary continuously during the winter. One of the most important properties of the snow cover is the density which defines many of its characteristics. Thermal properties of snow effect on the redistribution of heat in the snow cover and heat exchange with the environment. Snow cover alters the thermal and dynamic properties of the underlying surface and reduces the heat transfer between the earth and the atmosphere. It reduces the upward heat flux from the soil, which reduces heat loss to the atmosphere, reduces soil freezing and amplitude of temperature fluctuations. During thawing snow delays heat input to the soil. Snow and vegetation cover, topography, soil properties, its moisture content, as well as human activities are known as effecting on soil freezing.

Spatio-temporal variability of snow cover, being formed in accordance with the physical and geographical features of the study area, has an impact on the variability of the components of the landscape: meteorological and hydrological parameters, soil and vegetation cover.

Snow cover plays an important role in the functioning of ecosystems – the impact soil formation processes, the plant and animal life. A special soil climate creates under the snow, which differs greatly from the climate of the surface layers in areas devoid of snow cover, as well as the climate of the surface air. Preservation and accumulation of snowhas a great importance in the prevention of freezing winter crops, perennial grasses and planting of fruit crops.

Aim: identification patterns of the spatial variation of snow cover, and the formation temperature of the soil.

Objectives: 1) to investigate and compare the thickness of snow cover and soil temperature; 2) determine the relationship between snow cover and soil temperature; 3) to establish the nature of the spatial variability of these parameters.

Methods. Sample ground laid on stony slope of the ravine (the eastern outskirts of the city of Dnipropetrovsk, 48 ° 23'11 n.l 48 ° 23'11" v.d). Slope south-eastern exposurewith a slope 13 °. In the direction down the slope beam (beam perpendicular to the direction of the thalweg) 7 transects were laid at intervals of 3 m Each transect consists of 15 test plots at intervals as 3 m. Thus, the polygon is a regular grid of 15 × 7 size mesh 3 m. Selection of soil samples and measuring temperature, conductivity, soil and snow cover power produced at the control points – the corners of the squares. Measuring the temperature of the soil was carried out in a layer of 2-3 cm depth digital thermometer with an accuracy of 0,1 ° C. Measurements of soil temperature and snow cover, held on December 18 and 24, 2012. The tem­pe­rature during the measurements was -8.5° C December 18 and -10,5°Con December 24. The results of the temperature survey are shown on Table 1.

Table 1. Descriptive statistics of snow cover, and soil temperature

at a depth of 3 cm in the area grass-fescue-feather grass steppe

Findings

A linear relationship between snow cover and soil temperature in the steppe area is established. The relationship between snow cover and temperature increases with the total capacity of the snow cover. Spatial variability of soil temperature and snow cover repeat micro relief features of the polygon: the variability of snow cover directly affect spatial factors, the temperature of the soil is mediated by their snow cover effect.