地形强迫超长波在大气中传播的时间特性

本文用中纬度β平面准地转模式模拟地形强迫的超长波在大气中传播的时间特性.结果表明,超长波的垂直传播能力随着波长的增大而增强.在冬季的基本气流条件下,纬向波数1至3的超长波都能上传到平流层,而波数4以上的波只在对流层中才显著.结果还表明,地形强迫的超长波在形成一定时间后,将围绕某固定经度作东西向摆动,这种水平移动的准静止性是地形的动力控制作用的结果.这些结果与观测及其它理论研究的结果都较为一致.

THE TEMPORAL BEHAVIOR OFTHE PROPAGATION OF ULTRA-LONG WAVES FORCED BY TOPOGRAPHY IN THE ATMOSPHERE

In this paper,the temporal behavior of ultra-long waves forced by topography in winter is simulated by a β plan quasi-geostrophic model. It is shown that the ability of vertical propagation increases with increasing wavelength. Under the typical zonal mean flow in winter,the ultra-long waves with wave-numbers 1 to 3 can propagate upwards into the stratosphere,but the waves with larger wavenumbers are only significant in the lower troposphere. It is also shown that the ultra-long waves forced by topography tend to oscillate around certain longitudes and show stationary character due to the dynamic control of topography. These results are consistent with observation and the results deduced from other theoretical studies.