六种近地层湍流动量输送系数计算方案对比分析

The Comparison of Six Methods to Calculate Turbulent Momentum Transfer Coefficient of Near-surface Layer

选取30多年来近地层湍流通量研究中具有代表性的六种参数化方案,应用GAME/Tibet试验中那曲通量观测站的实测资料,对比分析了各方案计算所得的湍流动量输送系数(CM)之间的差异。结果表明:六种参数化方案计算得到的湍流动量输送系数之间存在较大差异。对于那曲观测站稀疏短草下垫面而言,稳定条件下当理查孙数小于0.1时,除Businger71方案存在显著低估以外,其他各方案均能较好估算湍流动量输送系数;不稳定条件下,Dyer74方案对湍流动量输送系数的估算效果最好,其次为Wang02,Launiainen95和Louis82方案,Businger71方案误差较大。

The momentum bulk transfer coefficient （ CM） is calculated by using six typical parameterization schemes and verified by the data of Naqu flux observation station of GAME（Global Energy and Water Cycle Experiment, Asian Monsoon Experiment）/Tibet Plateau Experiment. The results show obvious difference exists between results of the six schemes and the degree of difference is decided by the type of undersurface and the near surface stability. Wherein, schemes of Businger 71, Dyer 74 and B＆H91 must calculate the turbulent flux transfer coefficient by iteration and waste CPU time for numerical simulation. For flux data of Naqu observation station which is covered by sparse grass is considered, when the Richardson number is less than 0.1, all the other five schemes can do better estimation on the CM except the scheme of Businger in 1971 which has an obvious underestimation. Under unstable conditions, the scheme of Dyer in 1974 has the best estimation on the momentum bulk transfer coefficient （CM）, the schemes of Wang et al. in 2002, Launiainen in 1995 and Louis et al. in 1982 can also be used with gradually increasing error, and the scheme of Businger in 1971 has serious underestimation.