Abstract: The aerodynamic roughnees length Z₀, the zero-plane displacement d, the momentum drag coefficient C_D, water and heat drag coefficient C_H are calculated by using turbulence data and wind, temperature profile data observed in Changbai Mountain forest. The causes of the error in the method of calculating d and Z₀ are also discussed. The method based on the mass conservation principle is a practical one to calculate the aerodynamic roughness length and zero-plane displacement over tall vegetations. In Changbai Mountain forest, the roughness length Z₀ is about 1.6+-0.25m and the zero-plane displacement d is about 19.5+-1.38m. Drag coefficients C_D and C_H have a good relation with stability under unstable condition, and the average values of C_D and C_H are 6.6×10^-3 and 6.4×10^-31 in the neutral atmosphere, respectively.

Key words: canopy, aerodynamic roughness length, zero-plane displacement, drag coefficient, error analysis

摘要： 使用长白山阔叶红松林的风、温、湿梯度资料和超声风温仪测量的湍流资料，计算了长白山森林空气动力学粗糙度Z₀，零平面位移d、冠层上动量曳力系数 C_D及水热曳力系数C_H，并对d和Z₀的计算方法做了误差分析。树高26m的长白山原始森林空气动力学粗糙度Z₀=1.6m，零平面位移d=19.5m。基于质量守恒原理来计算高植被下垫面的动力学粗糙度、零平面位移是目前较为精确和实用的方法。要想得到较精确的d和Z₀，必须提高湍流通量μ'ω'和风廓线的测量精度，并确定合适的测量高度使得μ'ω'的测量和一点风速的测量在惯性副层内。在不稳定条件下，森林上空动量曳力系数C_D，水热曳力系数C_H与稳定度有较好的关系，近中性的平均代表值约为C_D=6.6×10^-3，C_H=6.4×10^-3。引入零平面位移d后，基于Louis方法计算曳力系数在粗糙的植被下垫面仍可使用。

关键词: 森林冠层, 空气动力学粗糙度, 零平面位移, 动量曳力系数, 水热曳力系数