Study Session 4 Flashcards
Pressure gradient force
Force that moves air from high pressure to low pressure
Coriolis force
When air is deflected to the right (northern hemp) due to earths rotation
Friction from earth affect coriolis from 3,000 AGL and below therefore wind direction can change closer to surface
Types of wind
Jet stream
Valley wind
Mountain wind
Katabatic wind
Jet stream
Narrow band of strong winds
Valley wind
Colder denser air settles downward and forces warmer air up mountain slope
Mountain wind
Air near mountain slope is cooled and sinks along slope (type of katabatic wind)
Katabatic wind
Wind blowing down an incline (incline a factor in causing wind)
Stable air characteristics
Stratified clouds
Smooth air
Fair to poor vis
Continuous precipitation
Unstable air characteristics
Cumuliform clouds
Turbulent air
Good vis
Showery precipitation
What is a temp inversion
When temp increase with altitude - associated with stable air
Wind shear happens at the meeting point (inversion point) of warm/cool
stable cold calm air below
Lapse rate
The amount of temperature decrease with increase in altitude
- help determine air stability
Types of fog
Radiation fog Advection fog Upslope fog Precipitation -induced fog Steam fog
Radiation fog
Shallow and forms at night or daybreak under a clear sky and calm wind. Small temp-dew spread point
Terrestrial radiation cools ground which cools air and form fog - restricted to land
Stronger winds than 5kt disperse fog but deepens in wind up to 5 kts
Advection fog, which is also called…
Forms when moist air moves over colder ground or water (sea fog)
Winds stronger then 15kts disperse it but it deepens in wind speeds up to 15 kts
Appear during day or night
Upslope fog
Air being cooled as it moves up a slope
Once wind ceases fog dissipates
Very dense and extends to high altitudes
