Geostrophic flow Flashcards
what is geostrophic wind
A geostrophic wind results from an equal and opposite balance between two forces, the horizontal pressure gradient force and the Coriolis
what happens when a column of air is heated
It expands, pressure falls less rapidly with height
what happens if a column of air is cooled
Then it condenses, pressure falls more rapidly with height
What way does air flow
From high pressure to low pressure
What happens if a surface is heated differentially
Air expands more rapidly at the warmer end
What does air expanding at the warmer end of a surface result in
A horizontal pressure gradient force and therefore a pressure gradient force. the pressure gradient force then causes air to move towards the region of lower pressure
What about the pressure increases with height above ground level
The pressure gradient and therefore pressure gradient force increases with height above ground level
In the pressure gradient force equation what does P mean
It means the density of air; this will be given where necessary, but near the surface it is 1.225 kg/m
What is dn in the pressure gradient force equation
Change in location (distance) in metres
What is dp in the pressure gradient force equation
Change in pressure, convert hPa to (in N/M squared) (hPa times 100 =N/m squared)
what is N in the PGF equation more in depth
N is the distance between the flow from higher pressure to lower pressure that you are calculating and can be measured irrespective of orientation provided n remains perpendicular to isobars
How does moving from high to low pressure effect our value of n
Will always be a negative value (down-gradient)
What are three important points about the Coriolis force
An apparent force, Deflects objects to the right in the northern hemisphere, impacts large scale flow over a period of a few hours
How can you calculate wubleu
Divide 2pi radians by the number of seconds in a day.
What is the value of wubleu
7.29 times 10 to the the minus 5 rad/sec
