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Vorticity. Reading: Ch. 14 N-G Online Reference: W&H 7.1.2 and 7.2.9. The whole equation… But what we care about most is the vorticity “around” the vertical axis, and we tend to call it just vorticity. EVALUATING RELATIVE VORTICITY. The Pinwheels .
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Vorticity Reading: Ch. 14 N-G Online Reference: W&H 7.1.2 and 7.2.9
The whole equation… • But what we care about most is the vorticity “around” the vertical axis, and we tend to call it just vorticity
The Pinwheels Çurvature and Shear Vorticity – whatever spins your wheel, man. By the way, it’s all relative.
f – The earth’s (planetary vorticity) Absolute Vorticity: Relative + Planetary (ζ+ f )
Vorticity, Divergence, and Intensifying Lows • Most of the other stuff is advection, but this term is important for low (E.T. Cyclone) intensification (large scales) • If the low deepens, vorticity must increase (winds stronger). For that to happen, must have convergence. Therefore, must have upward motion.
How to get vertical motion, let me count the ways… • The sub/supergeostrophic thing (downstream of troughs) • Jet streaks (4 quadrant model) • Strengthening and weakening of fronts • Topography • Also, frictional convergence – but that doesn’t really help a surface low deepen.
The last slide of 251 ! • Although it is not a causative relationship like the previous concepts, the Quasi-Geostrophic Omega (ω) Equation gives us the most powerful diagnosis tool of vertical motion and is the basis of modern forecasting practice. • Not time yet for the math, but here is the concept: