| 旋转流地转适应过程与能量转换规律 |
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| 作者姓名： | Fang Juan Wu Rongsheng |
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| 作者单位： | Fang Juan and Wu RongshengThe Key Laboratory of Mesoscale Severe Weather，Nanjing University，Nanjing 210093 |
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| 基金项目： | This work was supported by the National Natural Science Foundation of China under Grants Nos，the State Key Basic Program，江苏省自然科学基金 |
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| 摘 要： | 利用一维线性浅水模式从一个比较普遍的角度对地转适应过程中能量转换的特点进行分析。中首先考虑了两类不同的初始不平衡流的适应问题。一个是Gill所采用的质量不平衡模型，即初始场是静止的，只有水面扰动；另一个是Rossby中所考虑的动量不平衡模型，其初始不平衡流中只有风场的扰动，对这两个模型的适应过程而言，一个显的 特点就是能量转换率始终不会大于1／2或小于0，即适应过程中有位（动）能的释放和向动（位）能的转换，但释放出的能量最多只有其中的一半可以保留在最后的平衡场中。另外，本对任意初始不平衡流适应过程中的能量学特征也进行了分析，指出对于偏差场（相对于一定基本态）的动能和位能而言，上述能量转换关系依然成立。
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| 关 键 词： | 地转适应 质量不平衡 动量不平衡 能量转换率 动能 位能 |
| 收稿时间： | 21 July 2001 |
Energetics of geostrophic adjustment in rotating flow |
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| Fang Juan,Wu Rongsheng.Energetics of geostrophic adjustment in rotating flow[J].Advances in Atmospheric Sciences,2002,19(5):845-854. |
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| Authors: | Fang Juan Wu Rongsheng |
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| Institution: | The Key Laborator y of Mesoscatle Severe Weather, Nanjing University, Nanjing 210093,The Key Laborator y of Mesoscatle Severe Weather, Nanjing University, Nanjing 210093 |
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| Abstract: | Energetics of geostrophic adjustment in rotating flow is examined in detail with a linear shallow watermodel. The initial unbalanced flow considered first falls under two classes. The first is similar to thatadopted by Gill and is here referred to as a mass imbalance model, for the flow is initially motionless butwith a sea surface displacement. The other is the same as that considered by Rossby and is referred to as amomentum imbalance model since there is only a velocity perturbation in the initial field. The significantfeature of the energetics of geostrophic adjustment for the above two extreme models is that although theenergy conversion ratio has a large case-to-case variability for different initial conditions, its value isbounded below by 0 and above by 1/2. Based on the discussion of the above extreme models, the energeticsofadjustment for an arbitnary initial condition is investigated. It is found that the characteristics of the ener-getics of geostrophic adjustment mentioned above are also applicable to adjustment of the general unbal-anced flow under the condition that the energy conversion ratio is redefined as the conversion ratio betweenthe change of kinetic energy and potential energy of the deviational fields. |
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| Keywords: | geostrophic adjustment energy conversion ratio mass imbalance momentum imbalance kine- tic energy potential energy |
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