1 / 15

Gravity wave breaking over the central Alps: Role of complex topography

Gravity wave breaking over the central Alps: Role of complex topography. Qingfang Jiang, UCAR/NRL, Monterey James D. Doyle, NRL, Monterey, CA. Acknowledgements:. MAP scientists and staff. Large Scale Conditions. COAMPS Grid 1 1200 UTC (6 h) October 21, 1999 Terrain (gray scale)

avidan
Download Presentation

Gravity wave breaking over the central Alps: Role of complex topography

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. Gravity wave breaking over the central Alps: Role of complex topography Qingfang Jiang, UCAR/NRL, Monterey James D. Doyle, NRL, Monterey, CA Acknowledgements: MAP scientists and staff.

  2. Large Scale Conditions COAMPS Grid 1 1200 UTC (6 h) October 21, 1999 Terrain (gray scale) Wind vectors (500mb) Geopotential Height Contours (500mb)

  3. Terrain Electra flight track Turbulence Upstream Sounding

  4. SABL + Vertical Displacement

  5. GPS Dropsonde Trajectories 1 2 3 4 5 7 6 20km 100km

  6. Manual Isentropic Analysis of GPS Dropsonde Data 1 2 3 4 5 7 6 311 309 307

  7. Manual Isentropic Analysis of GPS Dropsonde Data 1 2 3 4 5 7 6 311 309 307

  8. Along Flight Track Wind Component 5 21 -2 5 20

  9. Vipiteno Soundings (0600, 0900 UTC)

  10. Flight Level Data Examples V (m/s) W (m/s) Potential temp. (K) Terrain (m)

  11. Turbulent Kinetic Energy TKE, Leg1 TKE, Leg2 Buoyancy Production Rates Terrain

  12. COAMPS, 4th mesh (~1 km) Potential temperature (solid contours) Along flight wind component (in grayscale) Turbulent kinetic energy (dashed lines)

  13. COAMPS 2D Idealized Simulations h=hw + hm*[1-cos(2πkx/a)] Smaller-scale terrain superposed on the lee-slope Smooth terrain

  14. Drag vs. Wave Number of Small Scale Terrain h=hw+hm*[1-cos(2πkx/a)] Where, hw: is the large-scale terrain height, a: is the large-scale terrain width, k: is the small scale terrain wave number

  15. Conclusions • The observed wave-breaking event was associated with the presence of a critical level, backward wind shear, and small Richardson number. • GPS dropsondes observed strong flow descent associated with severe down-slope winds, and local convective instability in breaking regions. The structure of the wave-breaking section resembles a hydraulic jump. • The underlying terrain and observed waves show multiscale features. • Idealized simulations indicate that small-scale terrain superposed on larger scale terrain promotes wave breaking and enhances downslope winds, turbulence, and drag.

More Related