Conservation of Potential Vorticity

Pole

q  Potential Vorticity      PV = f + z              f = planetary vorticity = 2Wsinf             z = relative vorticity = ¶v/¶x- ¶u/¶y q   f1 + z1 = f2 + z2             since f1 > f2  à z1 < z2 q  If z < 0, the vortex decreases rotation when moves toward lower latitudes and increases rotation when moves toward higher latitudes.

H (z1<0)

f1

H (z2> z1)

f2

Equator