一个深海定常风生流模式

A STEADY MODEL FOR DEEP SEA WIND-DRIVEN CURRENT

基于一定的实测资料,假定了深海垂直湍流系数的垂直分布。此基础上,从简化的动量方程中求得了定常风生流流速解,其主要结果是:(1)在中等海况下,表层风生流的右偏角约为24°;(2)对于弱海况,表层流大小与海面风速几乎成线性关系,而在高海况下要缓慢得多;(3)强海况下,有明显的逆风流,而在弱海况下,几乎不存在逆风流。

Based on certain observed data, the vertical distribution of vertical turbulent coefficient(Av) is assumed: Av = Avseaz, where Avs is the value at the sea surface and is direct proportion to the third power of sea surface wind speed, z is thevertical coordinate, positive downward and nondimensioned by thevertical Ekman friction scale, and a = 6πD/λ,λ being the averaged wind-wave len-gth. The main results of the wind-driven current solution derived from the simplified momentum equations are: (1) under moderate sea state, the right-inclined angle of the surface wind-driven current is about 24°; (2) for the weak sea state, the magnitude of surface current is almost directly proportional to the sea surface wind speed, but in the strong sea state, it is much lower:W*-(Ua)(1-δ)/2,W* is the dimensional wind-driven surface current speed, - 1 < 5 <0,δ=-1 for the weak sea state, and δ= 0 for the strong state; (3) the current solutions here have spiral structure like the Ekman model, but for the strong sea state there is obvious counter wind current which almost vanishes in the weak state case.