二维波状地形上的流场

在一个简化的二层模式中，求解大气波动方程，得到了二维波状起伏地形上扰动流线的分析解。研究了在上、下两层大气中，不同的温度廓线和风速廓线情况下，地形引起扰动的流场形式，同时讨论了支配扰动振幅的大气因子和地形特征。分析解的结果表明：若大气低层为深厚的不稳定层，地形引起的波动很微弱;如低层大气强稳定，上层大气弱稳定，则可能产生较强的波动;而当上层稳定度增加时，可产生非陷波，有利于高层动量下传，造成较大的地面风速。

Flow Field on a Two-dimensional Wave from Orography

In a two-layer model,the wave equation is solved to obtain the resolutionanalytically of disturbed streamlines caused by a two-dimensional sinusoidaltopography.The disturbed flow field in the upper and lower layers for varieties oftemperature and wind profiles is studied.The atmospheric conditions and thetopographic feature determining the amplitude of the disturbances are also discussed. The results show that the waves induced by the terrain are weaker if the lower layer ofthe atmosphere is deep and unstable,while the waves are stronger if the lower layer isstrongly stable with a weakly stable in upper layer.The increase of the stability in theupper layer may induce untrapped waves which favour the downward transport ofmomentum and the formation of the strong surface wind.