Altitudinal-belt variability of evapotranspiration of forest ecosystems in the mountains of Southern Siberia

Abstract

This work is devoted to the study of evapotranspiration in the landscape complexes of the northern macroslope of the Western Sayan. Article summarizes literature and authors’ data on evapotranspiration obtained at experimental watersheds in the basin of the river Kebezh, on one of which in the 70s, as an experiment, 50 % of the forest area in the watershed has been cut down. Calculations of the total evaporation of phytocenoses at the basin level has been made, taking into account the altitudinal zonality. To calculate evapotranspiration at the study sites, field data obtained as a result of silvicultural and geobotanical studies and hydrological observations were used. Based on interpretation of remote sensing images and the use of digital elevation model, classification of landscape-hydrological complexes for the basins of the Kebezh and Taigish rivers was carried out, for which the components of evapotranspiration were calculated. The results showed that evapotranspiration in the dark coniferous taiga of the Western Sayan is an important component of the water balance and a significant proportion is the unproductive consumption of moisture for the evaporation of precipitation intercepted by tree crowns. It has also been established that the structure of evapotranspiration changes along the altitudinal zones in accordance with the vertical differentiation of climatic parameters and vegetation productivity. Estimated evapotranspiration data for various landscape-hydrological complexes made it possible to an indirect estimates of their contribution to the formation of runoff in river basins. This study can serve as a theoretical guide for landscape hydrological studies in the temperate cool zone.

Keywords

• precipitation
• evapotranspiration
• river basins
• watersheds
• altitudinal zonality of landscape
• western sayan