Robock_Pub_23 Schlosser, C. Adam, Alan Robock, Konstantin Ya. Vinnikov, Nina A. Speranskaya, and Yongkang Xue, 1997: 18-Year land-surface hydrology model simulations for a midlatitude grassland catchment in Valdai, Russia. Mon. Weather Rev., 125, 3279-3296.


Off-line simulations of improved bucket hydrology and SSiB models are performed for a grassland vegetation catchment region, locted at the Valdai water-balance research station in Russia, forced by observed meteorological and simulated actinometric data for 1966-1983. Evaluation of the simulations is performed using observations of total soil moisture in the top 1 meter, runoff, evaporation, snow depth, and water table depth made within the catchment. The Valdai study demonstrates that with routine meteorological measurements and even in the absence of radiation data, long-term simulations of land-surface schemes suitable for model evaluations can be made. The Valdai data are available for use in the evaluation of other land-surface schemes.
Both the SSiB and the bucket models reproduce the observed hydrology averaged over the simulation period (1967-1983) and its interannual variability reasonably well, but some discrepancies in the models' seasonal behavior with respect to observations are seen. In addition, models cannot accurately and consistently reproduce extreme hydrological events. The bucket model's soil moisture variability is limited by its inability to rise above its prescribed field capacity for the case where the observed water table rises into the top 1 meter of soil, which can lead to erroneous simulations of evaporation and runoff. SSiB's results show that its runoff simulations disagree with observations, especially during the summer. The runoff discrepancies of SSiB can then lead to erroneous soil moisture and evaporation simulations.

Prepared by Alan Robock ( ) - Last updated on March 30, 1999