Ageostrophic flow Flashcards
When does Ageostrophic flow occur
When the PGF and Coriolis force are not equal and opposite
How can the two forces not be equal
Friction, Curved isobars, Small scale winds (cyclostrophic)
What part of the atmosphere is affected by the earths surface
The planetary boundary layer
What does friction change
Decreases average wind speed, increases surface flux heat, increases moisture and momentum and can increase gustiness of winds.
what happens to the impact of friction with heat
Decreases
What happens if we decrease our velocity due to friction
The magnitude of the Coriolis force is reduced (CF < PGF), there is less deflection to the right northern hemisphere and the direction of air flow is no longer parallel to the isobars, it is moving across them.
What is the angle a and how does friction create it
friction causes the Coriolis force to change direction and also the PGF. This change in pressure gradient force creates the angle a
what happens as you increase the height above the surface
Friction decreases, Coriolis increases, a decreases. This combination creates an Ekman spiral
What do curved isobars represent
Ageostrophic flow
What do curved isobars give rise to
The Centrifugal force
What is the magnitude of the centrifugal force derived from
Circular motion theory
What do curved isobars form
A gradient wind
What is the gradient wind equal to
The geostrophic wind + the centrifugal force
What is Anticyclonic flow known as
Super geostrophic flow
What is Cyclonic flow known as
Sub geostrophic flow
