Preliminary study of local land surface processes over Gobi in Arid Region of Northwest China

Using the data in "the Field Experiment on Land-atmosphere Interaction over Arid Region of Northwest China" carried out in Dunhuang, Gansu Province from May to June, 2000, the daily variations of surface radiation budget, heat balance and soil temperature over Dunhuang Gobi are analyzed. It is shown that the peak of global radiation is close to 1000 W.m(-2) and higher than that in other regions in a clear day. The averaged daily variations of sensible heat, latent heat and soil heat fluxes during the period of the experiment are very close to ones under the condition of a clear day. The parameters of land surface processes away from precipitation over Dunhuang Gobi are calculated. The mean of albedo, roughness length, soil wetness factor and soil heat capacity on experiment area, which are obtained by observation or estimation, are 0.255 +/- 0.021, (0.0019 +/- 0.00071)m, 0.0045 and 1.12 X 10(9) J.m(-3).K-1, respectively. The bulk momentum transfer coefficient C-d and bulk sensible heat transfer coefficient C-h between surface and atmosphere over Gobi are obtained according to three different methods. The result shows that these bulk transfer coefficients are different, but they are in the same order. Finally, the relation between the bulk transfer coefficients and the bulk Richardson number over Gobi are also discussed.