| 摘要: |
| 推导得到普遍形式的位涡度守恒方程,其条件是外源G和摩擦F组成的矢量M=Gq+BΔΛF散度为零,放松了位涡守恒的绝热无摩擦限制,对准地转位涡方程,利用WKB近似,得到了层结可变情况下的ROssby波的能量、波作用和拟能守恒的条件,对于空间缓变的基本气流,它们分别是基本气流与空间坐标无关,基本气流与x无关和基本气流是空间坐标的函数。最后还给出了地形存在情况下的Rocsby波的能量、波作用和拟能守恒的条件。 |
| 关键词: 缓变基流 地形 守恒律 |
| DOI： |
| 分类号: |
| 基金项目: |
|
| CONSERVATION CONDITIONS OF POTENTIAL VORTICITY AND WAVE ENERGY, ACTION AND ENSTROPHY FOR ROSSBY WAVES |
|
Lu Keli
|
|
Dept. of Atmospheric Sciences, Nanjing University, Nanjing, 210008
|
| Abstract: |
| In the paper a general conservation law of potential vorticity is obtained,the condition being that divergence of vector M=Gq+BΔΛF is zero, where G is the external source and F is the friction. The conservation laws of wave energy, action and enstrophy for Rossby waves are derived by using WKB approximation in a slowly varying basic flow and a variable stratification parameter, the conditions of conservation are that: (1) when the basic flow is independent of space coordinate the wave energy is conserved locally; (2) if the flow is independent of x, the wave action is conserved; (3) when the basic flow is of arbitrary slow variations, the wave enstrophy is conserved locally. Finally, the effect of topography is mainly of the slope of west-east direction and it causes only the variation of wave action. |
| Key words: Slow－varying basic flow Topograph Law of conservation |
