EFFECT OF WIND AND HYDROTHERMAL REGIMES OF SAND DUNE ON MOBILITY OF RELIEF FORMS

Abstract

The sandy pastures around the world are most often used year-round for cattle breeding. Here, desert sandy soils (Arenosols), which have become widespread, unlike the others, even with a short-term anthropogenic load, easily lose the texture of the surface horizon, which, under conditions of high wind activity, in a short time (5-7 years) turn into mobile sands and, with in the absence of work to fixing them, they quickly expand into hilly dunes. Due to the lack of vegetation in them, the processes of deflation and the appearance of foci of winding are rapidly developing. Such foci were formed in the Southern Balkhash region as a result of the intensive use of woody plants by local residents as a source of fuel and daily cattle passing. They thereby became, on the one hand, the "conductor" of desertification, and on the other hand, its victim. To restore the fertility of such formations, we wanted to understand first of all how dunes are created and how they undergo changes over time. Therefore, we studied the influence of the wind regime on the seasonal changes in their landforms, considering the wind and hydrothermal regimes. It has been established that the bare surface of sand dunes is strongly heated during the summer months, up to 45.0-46.0°С in its windward part and up to 47.2 and 52.0°С in the leeward part. And the humidity of the upper layer of a sand dune at the end of summer drops to a critical level (0.26%), which, under conditions of wind activity and aridity of the local climate, leads to the movement of sand masses by the wind from its windward to leeward part. This,in turn, in combination creates unfavorable conditions for the survival of plants.