Chapter 5 Flashcards
As you go up in elevation, what happens to temperature, air pressure and density
Temperature decreases as it goes away from earth
Air pressure decline and air will thin causing density to decrease
Air pressure is
The weight of overlying air acting in an area
Air pressure does 3 things
Acts in all directions
Will not collapse under weight
Air will push up at same pressure as it does down
Daltons law
Total pressure exerted by mixture of gases equals the sum of pressures produced by each constituent gas
Air pressure will
Decline with altitude
Why will air pressure decline with altitude
Because as you go up there is less air above you so there is less weight pushing on you, declining pressure
Surface area differs from____and variations are not always due to
One place to another. Differences in elevation of the land
What impacts air pressure and what has a larger influence
Temperature and density impacts air pressure with temperature having a bigger impact
When temperatures rise, what happens to kinetic energy and pressure
Kinetic energy will increase and pressure will decrease
Heated air is less
Dense and lighter and exerts less pressure on earth
Greater density of cold air vs warm at the same pressure will affect
The rate where air pressure drops with increasing altitude
Air pressure will drop more rapidly in altitudes with and why does this happen
Cold air because it is denser and has less kinetic energy
500 mb surfaces represent where
Half of atmosphere is above and half below by mass
Isobaric surfaces are
Surfaces of constant pressure
Isobaric surfaces will slope downward from
Relatively warm tropics to relatively cold high latitude
As humidity of air increases
Air density will decrease so there is less pressure
Why does water vapor reduce the density of air
Bc molecular weight of water is less than the average molecular weight of dry air
Cold dry air masses are what and produce what
Densest and produce highest surface pressures
Warm humid air masses are what and produce what
Less dense and produce lowest surface pressures
What can influence surface air pressure
Local conditions and air mass advection
A change in air pressure will occur with
Warm and cold air advection
What is convergence and divergence and what does it impact
They are wind patterns that are produced by a circular pattern where horizontal wind blow toward (converge) or away (diverge) from a location. They impact air pressure
Converging winds
Blow toward a column of air
Diverging winds
Blow away from a column of air
If more air diverges at a surface than converges
Air density and surface air pressure will decrease, forming a cyclone
If more air converges at a surface than diverges
Air density and surface pressure increase, forming an anti-cyclone
Air will diverge and converge from
Diverge from H and converge from L
Charles law states
When pressure is constant, absolute temp in kelvin’s is inversely proportional to density
Boyle’s law states
When temp is constant, air pressure is directly proportional to density
When pressure on a gas increases, what happens to density and volume
Density is directly proportional to pressure if temp is constant so it will increase but volume will decrease
Ideal gas law is
Combination of both Charles and Boyle’s law, where pressure is directly proportional to the product of density and temperature
At a fixed density, temperature and pressure are
Directly proportional
At a fixed temp pressure and density are
Directly proportional
At fixed pressure, temperature and density are
Inversely proportional
In the atmosphere, temperature, pressure and density can
Change simultaneously
Example of how temp pressure and density can change simultaneously in the atmosphere
When air temp rises, air will expand, density will decrease and so does air pressure
What happens to air density and pressure in the winter when temperatures drop
The air will drop and
air pressure will increase. Gas laws are satisfied bc density will increase as the temp drops since they are both inversely proportional to each other
As an air parcel rises, what occurs
Expansional cooling
What happens in expansional cooling
It expands, and pressure and temp both decrease
When an air parcel descends, what occurs
Compressional cooling
What happens in compressional cooling
It will compress and temp and pressure will increase
Adiabatic process
Change in temp where no heat is exchanged between air parcel and surroundings
What does the adiabatic process relate to
Expansional and compressional cooling
Temp of an ascending or descending unsaturated air parcel changes in response to
Expansion and compression only
Rate where Temperature of ascending or descending unsaturated parcel changes in response to expansion or compression only
Dry adiabatic rate
What does it mean when adiabatic rate is dry
Dry means it is any parcel not saturated with water vapor
Ascending unsaturated air will what and what will the sky cover be like
Cool at dry rate with sky’s being clear
Ascending saturated air will what and what will the sky cover be like
Will cool as lesser moist rate and sky’s will be cloudy
If moist rising air cools to point where relative humidity is 100% then
Air parcel is saturated and condensation and despotion will occur
Latent heat will release due to what and what will it counter
Phase of water change, countering expansional cooling which will cool air at lower rate than unsaturated air
What is released from a saturated rising parcel and when and what does it counter
Latent heat is releases during condensation or desposition that partially counter expansional cooling
