1 / 18

Vorticity

Vorticity. Vertical component of vorticity : i.e., the rotation about the local vertical. There are three types of vorticity used in geophysical fluid dynamics. If the wind is geostrophic, the geostrophic relative vorticity is given by. +. +. Vorticity. y. x. Divergence. Divergence:

benbow
Télécharger la présentation

Vorticity

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. Vorticity Vertical component of vorticity: i.e., the rotation about the local vertical There are three types of vorticity used in geophysical fluid dynamics If the wind is geostrophic, the geostrophic relative vorticity is given by

  2. + + Vorticity y x

  3. Divergence Divergence: From the continuity equation - For incompressible flow: Most meteorologists simply use divergence when they mean the horizontal divergence

  4. Divergence

  5. Vorticity and Divergence Why they are important? What’s the unit? What’s the order of the magnitude? Relative Vorticity (Synoptic Scales) Why?

  6. Vorticity and Divergence (Synoptic Scale) Relative Vorticity Same signs for both terms

  7. n - S Vorticity in Nature Coordinates V Curvature effect Shear effect The smaller the R (i.e., curved more, shorter waves), the stronger the curvature term. R is positive for cyclonic circulation and negative for anti-cyclonic circulation.

  8. Vorticity ? curvature Shear

  9. Ridge Trough Trough wind speed V L Vorticity Advection Relative vorticity advection Planetary vorticity advection 0

  10. Ridge Trough Trough V L Vorticity Advection (shorter Rossby waves) PVA Postive Vorticity Advection Wavelength (PVA)

  11. divergence aloft ascent z decreases with time convergence Adiabatic cooling Vorticity Advection (shorter Rossby waves) PVA (assume wave solution) PVA

  12. Ridge Trough Trough V L Vorticity Advection (shorter Rossby waves) Divergence PVA

  13. Ridge Trough Trough V L Vorticity Advection (shorter Rossby waves) Con. Div. NVA PVA Waves propagate eastward!

  14. z increases with time convergence aloft Adiabatic warming decent divergence Vorticity Advection (shorter Rossby waves) NVA (assume wave solution) NVA

  15. 564 Trough 570 576 PVA NVA U C wave speed Tropopause level of non-divergence 500-600 mb z C 0 speed Vorticity Advection (shorter Rossby waves) Wave propagation speed

  16. 564 Trough 570 576 PVA NVA U C wave speed z C 0 speed Vertical Coupling Tropopause level of non-divergence 500-600 mb H L Will grow Will grow

  17. 56 52 49 46 .. 39 37 5520 5460 cold air mass direction of propagation 32 31 ** L cold front warm air mass warm front . 988 992 996 Low-level cyclone and 500mb heights Upper and low-level coupled together – upper level trough enhances the low-level cyclone development.

  18. 5520 5520 5460 5460 L L Low-level cyclone and 500mb heights upper level trough catches low-level system – low level system is decaying. upper level trough is about to catch low-level system.

More Related