青藏高原大地形对冷涌作用的理论研究

THEORETICAL RESEARCH ON THE COLD SURGE OF THE QINGHAI-XIZANG PLATEAU AS A HUGE OROGRAPHY

中文摘要:

      本文从包含大地形效应的线性浅水波方程组出发,考虑青藏高原大地形为由西向东等科率倾斜,导得两类重力波解,一类是两个高频重力惯性波解,另一类是由地形激发的低频地形重力波解.后者与Kelvin波有某些类似之处.它们分别类似于数值试验所得冷锋迅速南下和冷涌强风速中心沿青藏高原大地形东侧边缘较慢向南传播的重力波.特别当无地形时,则低频波消失,仍有高频波.还求得了重力波波射线的传播路径为次摆线方程,这与数值试验所得冷涌强风速中心环绕青藏高原大地形东侧边缘的弧形路径颇为一致.且沿大地形下游沿海地区可能存在地形重力波波导管.

英文摘要:

      In terms of the linear shallow-water-wave equations involving in themselves:huge-topographic effect, two kinds of gravitational wave solutions are derived with the assumption that the plateau in question is a vast topography, inclined at a constant slope from west to east. One kind of the solutions is two high-frequency solutions of the inertia-gravitational wave pattern, another kind of that is one low-frequency solution of the orographic gravitational wave pattern excited by the huge-topography, the latter is similar to Kelvin wave in some ways. They are similar to the gravitational wave that the front of cold surge advances southward fast and to that the center of strong windspeed of cold surge moves towards the south along the eastern brim of the vast orography slow, respectively, the results are obtained by the numerical experiments. Especially, if it is no topography, the low-frequency wave vanishes but the high-frequency waves are available. It is also pointed out that the path of gravitational wave rays is a hypocycloid equation. The result agrees quite well with the path that indicates the center of the cold surge strong wind moves in a curved path along the eastern fringe of the Qinghai-Xizang Plateau. There might be the waveguide of orography-gravitational wave along the coastal areas in the east of the huge-topography.