Study of Parameterization of Surface Albedo of Bare Soilover the Gobi Desert in the Dunhuang Region
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Abstract
The relationships among surface albedo, solar elevation angle, and surface soil moisture over the Gobi desert in the Dunhuang region were analyzed by using the data of field observational surface radiation and soil moisture from May to October during a seven-year period. The results showed that the bare soil surface albedo decreases with an increase in solar elevation angle and tends to be a constant when solar elevation angle is larger than 40°. Surface albedo decreases with an increase in surface soil moisture content and shows a liner dependence on soil moisture. On the basis of the relationship of the bare soil surface albedo with the two factors of solar elevation angle and surface soil moisture content, a double factorial parameterization formula of the bare soil surface albedo is put forward over the Gobi desert in the Dunhuang region, which is more suitable for the surface albedo parameterization scheme in this area. The scheme proposed by this paper is able to reproduce the surface albedo "U" type of diurnal variation for accurate simulation of the dynamic trend of the surface albedo, in addition to accurate calculation of the bare soil surface albedo and reflected radiation. The variation characteristics as well as the trend of the bare soil surface albedo and reflected radiation are consistent with the observational data. Moreover, the calculated surface reflective radiation based on the parameterization scheme is also a good representation of the surface reflection and radiation characteristics of diurnal variation.
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