北京大学学报（自然科学版）

森林冠层空气动力学参数的确定

刘和平1, 刘树华1, 朱廷曜2, 金昌杰2, 孔繁智2, 关德新2   

  1. 1北京大学地球物理学系，北京，100871; 2中国科学院沈阳应用生态研究所，沈阳，110015
  • 收稿日期:1996-09-04 出版日期:1997-07-20 发布日期:1997-07-20

Determination of Aerodynamic Parameters of Changbai Mountain Forest

LIU Heping1, LIU Shuhua1, ZHU Tingyao2, JIN Changjie2, KONG Fanzhi2, GUAN Dexin2   

  1. 1Department of Geophysics, Peking University, Beijing, 100871; 2Institute of Applied Ecology, Academia Sinia, Shengyang, 110015
  • Received:1996-09-04 Online:1997-07-20 Published:1997-07-20

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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 CD及水热曳力系数CH，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CD，水热曳力系数CH与稳定度有较好的关系，近中性的平均代表值约为CD=6.6×10-3，CH=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

Abstract: The aerodynamic roughnees length Z0, the zero-plane displacement d, the momentum drag coefficient CD, water and heat drag coefficient CH 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 CD and CH have a good relation with stability under unstable condition, and the average values of CD and CH 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

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