干旱区生态环境知识资源中心

The characteristics of the surface radiation balance over desert and oasis in the HEIFE area were analysed and compared by use of the data observed at the Desert and Zhangye stations. The results show that ground surface plays an important role in the surface radiative energy budget, the non-uniform ground surface leads to a remarkable spatial variation of surface net radiation in the HEIFE area. Under a clear sky condition, the instantaneous fluxes of downward short-wave and long-wave radiations reaching the ground surface and their diurnal variations are nearly the same over desert and oasis in summer and winter. In summer, the difference of net radiation between desert and oasis (larger in the oasis by 11.2 MJ/m(2) day than the desert) is caused by the differences of surface albedo and upward long-wave radiation in the day-time, but upward long-wave radiation has a more significant influence. In winter, the thermodynamic conditions of the ground surface in the HEIFE area are nearly the same, and the upward long-wave radiation at both stations is nearly the same. As a result, the difference of net radiation between oasis and desert. (larger in the oasis by 1.43 MJ/m(2) day) is mainly caused by the difference in the albedo.