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The article presents a study on the variation of snow sublimation at three sites representing a variety of geographic and vegetative cover conditions in Mongolia. The snow sublimation values were calculated using the aerodynamic profile method and the results were verified by eddy covariance observations. Results show that sublimation variability was dominated by intense sublimation events characterized by daily sublimation exceeding 0-4 mm. Wind speed and air temperature are the dominant meteorological elements affecting sublimation. Annual sublimation averaged 11-7 mm at the flat plain meteorological station and 15-7 mm at the site in the mountains. The sum of snow sublimation and snowmelt evaporation represented 17 to 20% of annual evapotranspiration in a couple of observation years.

Environmental controls on evapotranspiration were investigated at a sparse grassland in Mongolia during 2003 and 2004. The study site was located on the southern periphery of the Eurasian cryosphere. Data from Eddy covariance, aerodynamic, and manual measurements were used in the analysis. A decoupling factor (Ω) was calculated to determine the relative importance of surface conductance and radiation to change in evapotranspiration rates. Higher evapotranspiration rates associated with a higher frequency of large Ω values revealed the importance of radiation forcing on evapotranspiration at this study site. As Ω increases', the aerodynamic conductance (ga) increased correspondingly but vegetation conductance (gc) decreased. Aerodynamic conductance (ga) was well fitted to an exponential function of the wind stress; gc clearly decreased as the vapour pressure deficit (all increased; gc related to air temperature through d. Although grass cover was sparse at the study site, the anticipated effect of soil moisture on E and gs was only slightly suggested and thus not deducible. On the 10-day-interval time scale, the effect of vegetation cover on evapotranspiration was insignificant compared to that of surface soil moisture. Changes in soil evaporation, related to precipitation, mainly caused the very large inter-annual differences in evapotranspiration. The relationship between evapotranspiration and surface bulk resistance at the study site could therefore be fit to an exponential function. [ABSTRACT FROM AUTHOR]