1 / 29

地形拖曳与举力

地形拖曳与举力. 南京大学大气科学学院 中尺度灾害性天气教育部重点实验室 王元.

pembroke
Download Presentation

地形拖曳与举力

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 地形拖曳与举力 南京大学大气科学学院 中尺度灾害性天气教育部重点实验室 王元

  2. Xu, X., M. Xue, and Yuan Wang(2013): Gravity wave momentum flux in directional shear flows over three-dimensional mountains: Linear and nonlinear numerical solutions as compared to linear analytical solutions. J. Geophy. Res., 118,1–12, DOI: 10.1002/jgrd.50471 • Xin Xu, Yuan Wang(Corresponding Author) and Ming Xue, 2012: Momentum Flux and Flux Divergence of Gravity Waves in Directional Shear Flows over Three-dimensional Mountains. J. Atmos. Sci.69(12): 3733-3744 • Yuan WANG, CAI Ning-Hao and TANG Jin-Yun (2008): A Two-wave Scheme for Orographic Gravity Wave Drag Parameterization. Acta Meteor. Sinica. 22(2):152-161 • TANG Jin-yun, TANG Jie and Yuan WANG(Corresponding Author)(2007):Analytical investigation on 3D non-Boussinesq mountain wave drag for wind profiles with vertical variations. Applied Mathematics and Mechanics, 28(3): 317-325. • 唐锦赟：由复杂地形触发的重力波地表拖曳问题的计算及其参数化方案设计的理论研究（硕士论文） • 王宛亭：中国中东部地区Pielke地形谱解析及大气重力波拖曳（硕士论文）

  3. Scientific Motivation 拖曳力（湍流动量通量） 北半球中纬度冬季纬向平均风 王宛亭（2003）

  4. Scientific Motivation 温度过低 风速过强 McFarlane(1987)

  5. Polar Westerly Bias N North Hemisphere S

  6. Wavestress Dissipation Scientific Motivation 引言（三）重力波拖曳参数化示意图 U(z)

  7. 高气压扰动 减速 来流 加速 低气压扰动 地表拖曳 Surface Drag 地表面 Bernoulli定理

  8. 地形重力波拖曳（TGWD）的双波参数化方法可有效解决西风偏差 (westerly bias)的问题 平流层顶西 风急流位置 地形拖曳力的垂直廓线 北半球中纬度冬季纬向平均风 地形重力波拖曳（TGWD）的双波参数化准确地再现了当TGWD增强，平流层顶西 风急流减弱的过程 TANG Jin-yun (2007); Yuan WANG(2008)

  9. p1 p2 u Scientific Question 地表拖曳≈地表扰动动量垂直传输 各高度拖曳 ≈各高度扰动动量垂直传输 各高度拖曳的垂直变化 ≈各高度扰动动量垂直传输的垂直变化 ／ ＝ 举力（Lifting Force) (Xin Xu, Yuan Wang(2012), JAS)

  10. Scientific Question τ 风速随高度发生方向旋转时，地表净拖曳矢量与地表风速矢量不重合，表现出举力特征。唐锦赟(2005)

  11. Lift Lifting Effect streamline

  12. Method Equation Perturbation Wave + Topography Drag Lifting

  13. Theoretical Framework(Eq.+ Perturbation)

  14. Theoretical Framework (Wave)

  15. Theoretical Framework (Wave)

  16. Observation of Mountain Waves Cap Clouds Foehn Effect L. and Rotor Clouds

  17. Theoretical Framework (Drag )

  18. Theoretical Framework (Drag ) Surface Drag Drag at z-level

  19. Theoretical Framework (Lifting )

  20. Example

  21. Example

  22. Illustration

  23. Discussion 遇到地形时，台风路径的打转…（天气预报） new wave drag parameterization schemes would be needed to properly account for directional shear effects!(参数化设计） directional wind shear can also introduce asymmetric development in the wake flow to trigger lee vortex shedding！（动力学）

  24. 谢 谢！ 王元 yuanasm@nju.edu.cn

  25. Lifting Forcing that we found and theoretically proved . • Xin Xu, Yuan Wang(Corresponding Author) and Ming Xue, 2012: Momentum Flux and Flux Divergence of Gravity Waves in Directional Shear Flows over Three-dimensional Mountains. J. of the Atmospheric Sciences(JAS), 69(12): 3733-3744 • 唐锦赟：由复杂地形触发的重力波地表拖曳问题的计算及其参数化方案设计的理论研究（硕士论文） • 王宛亭：中国中东部地区Pielke地形谱解析及大气重力波拖曳（硕士论文）

More Related