摘要
利用含湍流粘性的β平面正压海洋线性扰动方程组和刚盖近似,针对大陆架上为指数剖面、深海大洋为平坦的海底地形以及任意走向的直线海岸线,研究得到了流函数的图象和相应的波频散关系以及波的约束条件,讨论了摩擦、β效应、海岸线的走向和陆架宽度对波动性质的影响。
This paper deals with the influences of bottom friction,variable Coriolis’parameter,coastline orientation and shelf width on the coastal trapped waves in a linear barotropic model ocean with a given exponential depth profile in the continental shelf region and constant depth in the deep-sea region.The main results obtained are as follows.1.B-effect of non-westward and/or non-eastward oriented coastlines result in wave propagation along arbitrary horizontal direction for the coastal trapped waves.2.Two wave trains travel with opposite directions and unequal frequencies(i.e.10^(-5)s^(-1)and 10^(-10)s^(-1)respectively)for all orientations of coastline with the exception of the coastline with westward and/or eastward orientations.3.The phase velocity depends on wavelength,coastline orientation,latitude,variable Cotiolis’parameter,bottom topography and shelf width whether the bottom friction is taken into account or not.4.The phase velocity does not equal to the group velocity in magnitude.The directions of the wave phase and energy propagations are connected with each other conditionally.5.When the water depth increases with distance perpendicular to the coastline and ignoring B-effect,the wave travels in one direction with the coast to the right in the north hemisphere.On the contrary,,when the water depth decreases with distance perpendicular to the coastline,the opposite conclusion holds true.6.Either the variable Coriolis’parameter and non-westward and non-eastward oriented coastline or the bottom friction could make the wave amplitude changeable with time.Actually whatever the coastline orientation is,the wave amplitude will almost be attennated by the bottom friction coefficient.7.The ratio of the wave frequency(w_(r))_(2)to fo decreases gradually with increasing non-dimensional wave number lLs.This trend is independent of the variation of coastline orientation and shelf width.However,the regularity that the ratio of wave frequency(w_(r))_(3)to fo decreases with increasing lLs is merely valid within certain range of wave number.Both phase and group velocities change signs beyond certain wave number bounds.8.With the exception of coastline which lies westward or eastward,the correction of variable Coriolis’parameter to the wave frequency(w_(r))_(3)becomes increasingly important especially for the shelf width somewhat less than 200km.9.The constrains for the existing waves can be derived in very possible case.
作者
秦曾灏
刘秦玉
Qin Zenghao;Liu Qinyu(Shanghai Typhoon Institute;Shandong College of Oceanography,Qingdao)
出处
《海洋与湖沼》
1988年第1期8-17,共10页
Oceanologia Et Limnologia Sinica
