ESS227
Prof. Jin-Yi Yu
Example
•Suppose that the air within a circular region of radius
100 km centered at the equator
is initially motionless with respect to the earth. If this circular air mass were moved to the
North Pole along an isobaric
surface preserving its area, the circulation
about the circumference would be:
C = −2Wπr2[sin(π/2)
− sin(0)]
•Thus the mean tangential velocity at the radius r = 100
km would be:
•
V
= C/(2πr) = − Wr ≈ −7
m/sec
•
•The negative sign here indicates that the air has acquired anticyclonic relative circulation.