Abstract:

In this study, the values of soil composition at Xiaotang Observation Station in the northern margin of the Taklimakan Desert were measured by Mastersizer-2000 Laser Particle Sizer and analyzed. Soil composition was classified according to the Wooden-Wendward Particle Size Standard. It was found that the soil was not the homogeneous sandy soil, and there was 10%-24% clay in the shallow soil layer at 0-30-cm depth. The soil parameters in the Noah Land Surface Model were recalculated according to the proportions of soil compositions. The data observed at Xiaotang Station from March 22 to July 25, 2011 were used to drive the Noah model, and the simulated results before and after amending the soil parameters were compared. The results showed that, after updating the soil parameters, the simulation effect of soil temperature was improved, the deviations of soil temperature, soil heat flux, sensible heat flux and surface net radiation were reduced by 0.62 ℃, 10.47 W·m^-2, 7.02 W·m^-2 and 5.48 W·m^-2 respectively, and the efficiency coefficient was more acceptable. The overall effect of soil parameter modification for the Noah simulation was analyzed by Taylor diagram. The results showed that the heat transfer and diffusion in the modified soil parameter model could be improved to a certain extent, and the simulation effect of soil temperature could be improved obviously.

Key words: desert; soil composition, land process, Noah model, Taklimakan Desert