| Ekman动量近似下中间边界层模式中的风场结构 |
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| 作者姓名： | Tan Zhemin Wang Yuan |
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| 作者单位： | Tan Zhemin and Wang Yuan Key Laboratory of Meso-Scale Severe Weather/ MOE. Department of Atmospheric Sciences，Nanjing University，Nanjing 210093 |
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| 基金项目： | National Key Basic Research Project: Research on the Formation
Mechanism and Predication Theory of severe synoptic Disasters in |
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| 摘 要： | 发展了一个准三维的、中等复杂的边界层动力学模式，该模式包含了EKman动量近似下的惯性加速度和Blackadar的非线性湍流粘性系数，它进一步改进了Tan和Wu(1993）提出的边界层理论模型。该模型在数值计算复杂性上与经典Ekman模式相类似，但由于包含了Ekman动量近似下的惯性项，使得该模式比传统Ekman模式更近于实际过程。中详细地比较了该模式与其他简化边界层模式在动力学上的差异，结果表明：在经典的Ekman模式中，由于忽略了流动的惯性项作用，导致在气旋性切变气流（反气旋性切变气流）中风速和边界层顶部的垂直速度的高估（低估），而在半地转边界层模式中，由于高估了流动惯性项的作用，结果与经典Ekman模式相反。同样，该模式可以应用于斜压边界层，对于Ekman动量下的斜压边界层风场同时具有经典斜压边界层和Ekman动量近似边界层的特征。
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| 关 键 词： | 风场结构 Ekman动量近似 边界层模式 惯性加速度 斜压边界层 |
| 收稿时间： | 26 March 2001 |
Wind structure in an intermediate boundary layer model based on Ekman momentum approximation |
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| Tan Zhemin,Wang Yuan.Wind structure in an intermediate boundary layer model based on Ekman momentum approximation[J].Advances in Atmospheric Sciences,2002,19(2):266-278. |
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| Authors: | Tan Zhemin Wang Yuan |
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| Institution: | Key Laboratory of Meso-Scale Severe Weather/ MOE, Department of Atmospheric Sciences. Nanjing University, Nanjing 210093,Key Laboratory of Meso-Scale Severe Weather/ MOE, Department of Atmospheric Sciences. Nanjing University, Nanjing 210093 |
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| Abstract: | A quasi three-dimensional, intermediate planetary boundary layer (PBL) model is developed by including inertial acceleration with the Ekman momentum approximation, but a nonlinear eddy viscosity (1993). The model could keep the same complexity as the classical Ekman model in numerical, but extends the conventional Ekman model to include the horizontal accelerated flow with the Ekman momentum approximation. A comparison between this modified Ekman model and other simplified accelerating PBL models is made. Results show that the Ekman model overestimates (underestimates) the wind speed and pumping velocity in the cyclonic (anticyclonic) shear flow due to the neglect of the acceleration flow, however, the semi-geostrophic Ekman model overestimates the acceleration effects resulting from the underestimating (overestimating) of the wind speed and pumping velocity in the cyclonic (anticyclonic) shear flow. The Ekman momentum approximation boundary layer model could be applied to the baroclinic atmosphere.The baroclinic Ekman momentum approximation boundary layer solution has both features of classical baroclinic Ekman layer and the Ekman momentum approximate boundary lager. |
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| Keywords: | Wind structure Ekman momentum approximation Boundary layer model |
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