we recorded many ecohydrological observations at a sparse grassland site on the southern periphery of the Eurasian cryosphere in Mongolia. Grass growth at the study site shows significant difference of biomass between drier and moister years. Seasonal change of PAR albedo is a good indicator of temporal change of biomass. The stresses of atmosphere and soil water to grass have been evaluated at the study site using index of air temperature stress degree-day (SDD) and soil water stress (SWS). SDD was small and prevailingly negative. Variations in the SWS tracked precipitation fluctuations. Variability of two indexes may imply that atmospheric heat stress for the growing grass was weak compared to soil water stress for such a semiarid region. The above conclusion is supported by irrigation experimental observation as well; clear differences of biomass were observed between watered and unwatered ground after irrigation commenced. Soil evaporation and transpiration were estimated using a soil moisture parameterization and verified with micro-Lysimeter observations. Variability of evapotranspiration shows temporal decline processes' response to precipitation events or snow melting. During the observation period, evapotranspiration totaled 301.6 mm, and precipitation totaled 319.5 mm. The mean partition of transpiration in evapotranspiration was 22%, which was small during wetter grass-growing periods but large in drier periods. The growing period is short along the periphery of the cryosphere, but water fluxes during the growing period contribute significantly to the annual water cycle.

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The joint Japan-Mongolia-USA project DUVEX (DustVegetation Interaction Experiment) was designed to develop a biogeophysical model which can simulate dust emission and ecosystem processes over the vegetated land surface. Dust emission processes have been investigated mostly on bare land, and there is very little information about vegetated land. Thus, intensive observations were conducted of a dust event that occurred on the Mongolian steppe on 24 April 2008.Meteorological and dust elements (e.g., saltation flux, visibility, dust concentration) and land-surface parameters (e.g., roughness length, vegetation cover, and the ground-based normalized difference vegetation index) were measured. During the event (from 13:00 to 18:00 LST on 24 April), the threshold wind speed at 1.54 m height, which is the minimum wind speed inducing saltation of particles ranging from 30 to 667 μm in diameter, was 8. m s −1 on a land surface with 7.2% vegetation cover with dead brown leaves, a small roughness length (0.0058 m), and a very dry sandy soil at 0−5 mm depth (water content, 0.002 g g −1). For comparison with previous studies, the threshold wind speed value was converted to the values at the heights in each study by using the logarithmic law of wind profile. Our value is close to the SYNOPderived values for the same area, but larger than ground-observed and SYNOP-derived values for East Asian deserts.