Geostrophic Wind & Gradient Wind
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Transcript of Geostrophic Wind & Gradient Wind
Geostrophic Wind
and
Gradient Wind
Praveen Kumar SinghM. Sc. Environmental Science
Central University of Rajasthan
The Geostrophic Equation
Expresses the magnitude of the wind speed as a functionof the geopotential height gradient on a constant pressuresurface.
Where, go = gravitational acceleration,f = Coriolis parameter = 2Ωsin(Φ).Ω = angular velocity vector of the planet (7.292 x 10-5 s-
1 )f ranges from -1.4 x 10-4 s-1 at South Pole to +1.4 x 10-4
s-1 at the North Pole.f ≈ about 1 x 10-4 s-1 for mid-latitudes.
Zf
gv h
og
Geostrophic winds exist in locations where there are nofrictional forces and the isobars are straight. Isobars arealmost always curved and are very rarely evenlyspaced. This changes the geostrophic winds so thatthey are no longer geostrophic but are instead ingradient wind balance.
Gradient Wind