粗糙度和稳定度对绿洲生态系统能量平衡的影响

研究了粗糙度和稳定度等对绿洲生态系统能量平衡的影响。地表粗糙度和大气稳定度是控制地气间能量交换的重要因子，研究表明，绿洲中植被的温度不仅受反照率、空气温度影响而且受大气稳定性和地表粗糙度的影响，在其他条件相同的情况下，大气稳定度越高（低），植被的温度越高（低），地表粗糙度越小（大）植被的温度也越高（低）。研究还发现，绿洲中总的蒸散量的多平衡态特征只有在稳定度低的时候出现。在相同的气候条件下，低矮的植被在干旱半干旱地区更容易发展起来。另外研究了层结不稳定和层结稳定的情况下绿洲生态系统能量交换的差异。

The Influence of Roughness and Stability on the Energy Balance of Oasis Ecosystem

The temperature of vegetable and the total evapotranspiration rate of the oasis, while vegetation and bare soil coexist, are calculated by using the energy balance equations of vegetable and bare soil. The aerodynamics drag coefficient, roughness and stability are introduced. Roughness parameter can reflect the character of the underlying surface. The character of atmospheric stratification is described by using stability.The temperature of vegetable and the total evapotranspiration rate of the oasis depend on climatic and ecological conditions, such as the albedo of vegetable and soil, air temperature, roughness and stability. When the stability increases, the vegetable temperature will increase. Also, when the roughness of vegetable decreases, the vegetable temperature will increase except when roughness of vegetable is bigger than 0. 05. When the roughness of vegetable is bigger than 0.05, its change almost has no influence on the temperature and the total evapotranspiration rate of the oasis. When the stability is weak, in some conditions, the solutions of evapotranspiration rate can appear in a multi-equilibrium state. Under the same climatic conditions, dwarf vegetables are easier to expand to the total oasis in the area of drought and semi-drought. When the stability increases, the multi-equilibrium disappears. For instability, multi-equilibrium state solutions of evapotranspiration rate appear easily.