Pressure And Wind Flashcards
What is air pressure, high and low pressure
Air pressure = weight of the atmosphere, size and number of particles.
High pressure = air descends and diverges gets warmer. Associated with sunny and clear skies
Low pressure = air converges and it ascends, associated with stormy/cloudy weather.
What is average sea level pressure?
1013.2mb
How is wind defined?
Horizontal movement of air produced by differences in pressure
3 properties:
Direction = measured where it’s coming from (16 principle directions, cardinal directions)
Speed = measured with an anemometer
Character = gusting, steady, variable…
What is atmospheric circulation?
Looked at 3 different levels, global, regional, local.
Global winds effected by 4 forces
1 - gravity force
2 - pressure gradient force, high to low pressure - biggest influence on the speed/force of wind
3 - coriolis force - rotation of earth appears to deflect winds (right in northern hemisphere
4 - friction force, topographic features that create drag on wind
Lethal humidity is…
High humidity and high relative temperature.
What are the different elevation classes of clouds by elevation?
Low = 2000m cirro clouds
Medium = 4000m alto clouds
High = 6000m just described by shape
Clouds are also named by shape
What are the clouds names by shape
Stratus is layers/flat
Cumulus is fluffy
Cap clouds form over mountains and float away - lenticular
What are things that cause atmospheric liftjng?
Convergence, where air masses meet, equater
Convection, local heating causes warm air to rise
Orthographic, passage of air over mountains
Frontal uplift, warm air moves up and over cold air
400km long, 40km an hr winds, cirrus clouds 1 to 2 days prior, cumulonimbus building, sudden.
How do midlatitude cyclones work?
Their birth (cyclogeninisis)
Low pressure forms and air masses meet along west coast of NA
Their maturity/open stage
Warm and cold fronts and form moving in the same direction
Counterclockwise flow around low pressure system
Old age/occurred stage
Cold front gets stronger and faster and takes over the warm front
Dissolution stage
Storm dissipates as energy is lost
What is experienced on the ground during a cold front?
Wind, cold, precipitation
Rapid changes in wind
Sudden drop in pressure
