不稳定边界层下地形重力内波

Mountain Gravity Internal Waves in the Lower Unstable Boundary Layer

水槽实验及线性理论研究表明 ,当低层大气处于近中性或不稳定时 ,如果地形引起的动力扰动足够强 ,地形扰动可在上部稳定层结中激发出重力内波 ,波动反过来影响低层流场 ,引起动量输送。低层大气处于近中性或不稳定时 ,地形波同样对大气运动可产生波阻 ,这应引起模式工作者的重视。最后讨论了大气粘性对中性或不稳定层结下地形波的影响。

According to tank experiments and theoretical analyses, if the elevation of the terrain is close to the upper stable layer the vertical disturbances induced by the terrain may stimulate internal waves in the upper stable layer even though the lower atmospheric boundary layer is neutral or unstable. The waves may in turn influence the flow fields in the lower layer and lead to momentum flux. The mountain waves may exert wave drags to the atmosphere even though when the lower atmospheric boundary layer is neutral or unstable. These phenomana should be taken into consideration in performing a large scale numerical model or a climate model. The effects of the atmospheric viscosity (represented by the linear Rayleigh friction) on the mountain waves are also discussed when the lower atmospheric boundary layer is neutral or unstable.