利用锡林浩特草原平坦下垫面塔层湍流资料,对常值通量层的高度进行了估计,检验了局地相似理论在均匀草原下垫面的适用性,对Monin-Obukhov相似理论和局地相似理论在常值通量层以上的大气边界层的适用性进行了比较。结果表明：（1）对于锡林浩特草原来说,常值通量层厚度在50m左右;（2）通过分析无量纲风速和温度梯度、无量纲风速方差、无量纲标量（温度T、水汽q、CO2浓度C）方差与稳定度z/L之间的关系,验证了局地相似理论在均匀草原下垫面70m以下大气边界层的适用性;（3）感热通量尺度与浮力长度尺度之间存在线性关系;（4）从经典Monin-Obukhov长度、局地Monin-Obukhov尺度和浮力长度尺度的对比分析来看,局地尺度更适用于50m以上的大气边界层,而浮力长度尺度不适用于50m以上的大气边界层。“,”The applicability of local similarity of the boundary layer of in the underlying surface Homogeneous grass land is examined using the turbulence observation data at meteorological tower.The height of constant flux layer is estimated.The extension of suitability of Monin-Obukhov and local similarity theories in the boundary layer upper constant flux is also discussed.The results show that the height of constant flux layer is about 50 m.The heat flux length scale is proportional to the buoyancy length scale both in the stable and unstable boundary layers.In contrast,the local Monin-Obukhov length is more suitable in describing the stability dependence of the similarity functions upper 50 m boundary layer than the buoyancy length scale.