The Influence Of Vegetation On Reflected Solar Radiation In Arid And Extra-Arid Zone Of Mongolian Gobi

Abstract

Vegetation cover has a noticeable effect on surface reflectivity and local microclimate in arid areas of Mongolian Gobi. Over the past decades, various shrub species (Haloxylon ammodendron and Calligonum mongolicum) have appeared on the previously unvegetated hamada. The climatic consequences of bush encroachment are still poorly understood. Using the experimental data, this article estimates the reflectance of plants dominating in Mongolia’s dry steppe, desert-steppe, and desert ecosystems. The average values of the total reflection coefficient at visible and infrared wavelengths range from 19.7% ± 1.4% to 20.1% ± 1.7% in plants growing in desert-steppe ecosystems, and from 25.0% ± 0.9% to 24.8% ± 1.5% on the bare surface. The difference between the reflectance of vegetated and unvegetated surfaces reaches 5%. Therefore, in daylight hours, the vegetated day surface loses less solar energy than the non-vegetated surface does. This phenomenon may be defined as a quasi- or secondary greenhouse effect – in daylight hours, solar energy is retained on the surface by vegetation and this contributes to the temperature increase. Such an impulse, which seems to be insignificantly small at first glance, triggers a series of climatic variations leading to a change in the structure of the radiation and heat balance as well as the climate not only in the desert-steppe and desert ecosystems but also in Central Asia as a whole. All this may explain the 1.2-2.3°C increase in air temperatures in the Gobi observed over the last 25 years.

The Dynamic Structure of Plant Communities in Dry Steppes Central Mongolia

“…The main research was carried out on the territory of the Bayan-Undzhul somon, which is located 150 km from the capital of Mongolia. From 1972 to 1976 and 1984 the staff of the Joint Russian-Mongolian Complex Biological Expedition carried out a stationary study of the vegetation of dry steppes here [1,4,5]. In 2007-2011.…”

“…Mongolia's steppe ecosystems, used mainly as natural pastures, cover an area of 6,722,912 km 2 , or almost 55% of the country's territory. In recent decades, the increased grazing pressure on ecosystems has changed the natural balance due to the increased vulnerability of semi-arid and arid ecosystems, which contributes to their degradation and desertification [1][2][3][4][5]. In this regard, the phytocenotic study of the composition of species and biomorphs, vertical and horizontal structures, as well as the nature and characteristics of the production process of plant communities of dry steppes in Central Mongolia is of particular relevance.…”

Perspectives for Photocatalytic Decomposition of Environmental Pollutants and Pathogens on Photoactive Particles of Soil Minerals

“…Different situation is Earth' part with sparse vegetation, these are primarily the desert, semi-desert and tundra zones. The supply of solar energy is much higher, because of low soil shading [220,221]. In the polar climate (tundra zone), the radiation is limited with large seasonal variability, including polar nights [222].…”

Xerophytic and halophytic shrubs as the main biomaterials for phytomeliorational resource-saving technologies in arid lands

“…The effect of salts on plants and their salt tolerance, the negative effect of salts on plants can be differentiated into three components: osmotic, toxic, and specific [2,3].…”