Characteristics of land-atmosphere interaction parameters in hinterland of the Taklimakan Desert

The importance of the energy exchange between the land surface and the atmosphere can be characterized by bulk transfer coefficients for momentum, C(d), and heat, C(h). The diurnal and monthly variations of both bulk transfer coefficients and lengths of surface roughness are analyzed. Based on observed data from January to December 2009 in hinterland of the Taklimakan Desert, the characteristics of aerodynamic roughness length, z(0m), and thermal roughness length, z(0h), are discussed. It should be noted that the diurnal and monthly variations of the parameters are fundamentally different from those reported in vegetated areas. Specifically, four unique features can be identified in the surface layer. First, in Taklimakan Desert, z(0m) does not vary with seasons; however, it significantly depends on wind speed. Second, z(0h) is higher in the daytime and lower at night, showing obvious diurnal characteristics. The high values appear at sunrise and sunset. Third, both C(d) and C(h) have two peaks, one peak at sunrise, and another one at noon. Fourth, both C(d) and C(h) have larger values in winter season and smaller values in summer season.