Week 1 through Week 4 Flashcards
what is the atmosphere?
mixture of gas molecules, small suspended particles of solid and liquid, and falling precipitation
what is the difference between climate and weather?
Weather refers to the short-term phenomena.
Meanwhile, climate refers to the long-term pattern.
Which way does air pressure go?
From high pressure centers to low pressure centers
In low pressure areas, what are there?
rising air and clouds
In high pressure areas, what are there?
sinking air and clear skies
what is density?
mass (kg) per unit volume (m3)
As altitude increases, what occurs to density.
As altitude increases, density decreases. This may be expressed in terms of the mean free path, or average distance a molecule travels before colliding with another molecule. Due to compressibility, atmospheric mass gradually “thins out” with height.
what occurs when molecules bounce around?
they have a velocity and kinetic energy associated with it.
KE= 1/2 * m * v^2
As kinetic energy increases, what does temperature do?
As kinetic energy increases, temperature increases. When the temperature is high, it just means that air molecules are moving slightly faster than usual!
What relationship do kinetic energy and temperature have?
direct relationship.
what is pressure?
pressure is force divided by unit area
Which direction does pressure go in?
Molecules move in all directions, so pressure is exerted in all directions.
how is force produced?
the collision of molecules
What relationship do density and pressure have?
Direct relationship
Suppose that instead we keep the density constant and increase the temperature of the gas. What happens to the pressure of the gas?
Pressure increases as we increase temperature
What happens if we increase the temperature of the gas?
Higher temperatures increase kinetic energy, and pressure results from the force cause by collisions of molecules with the surface. If we increase the temperature, there will be stronger collisions and higher pressure.
What relationship do pressure and temperature have?
direct relationship.
What is the ideal gas law?
pressure= density* gas constant * temperature
If density decreases with height, what occurs w/ pressure at low elevations and higher elevations?
pressure decreases most rapidly at low elevations and gradually tapers off at greater altitudes
What is in the troposphere?
Layer of virtually all weather processes.
• Warmed at the surface by solar radiation.
• Steady temperature decrease with height.
• The top of the troposphere is called tropopause.
What is in the stratosphere?
ozone layer
What is in the mesosphere?
coldest layer
What is in the thermosphere?
low density, almost no mass
Name three ways in which energy/heat transfer can be transferred from one place to another.
Radiation, conduction, convection
Radiation
•The transfer of energy by electromagnetic waves.
•Continually emitted by all substances.
•requires no physical medium (can occur through empty space).
example: the sun heats the ground
Conduction:
The transfer of energy between objects that are in physical contact.
Example: the ground heats the air
Convection:
the transfer of energy between an object and its environment due to fluid motion
example: the warm air rises
PGF is related to:
Newton’s second law which states acceleration implies action of a net force
What relationship to PGF have to distance between isobars?
direct relationship
PGF goes from high to low pressure
What is hydrostatic balance?
The balance between the vertical pressure gradient force and the gravitational force
What do local imbalances do (in relation to hydrostatic balance)?
Local imbalances create vertical motion
(updrafts and downdrafts)
In zones of sinking air, PGF is less than gravitational force. In zones of rising air, PGF is greater than gravitational force.
If you heat a column of air, what will occur?
the density will decrease because heating decreases density. the column contains the same amount of air, but has a lower density to compensate for its greater height.
“warmer atmosphere is deeper”
What can the height of isobaric surfaces show?
Constant pressure surfaces of cooler air will be lower in altitude than those of warmer air.
High heights of isobaric surfaces (e.g., 500-mb surface) correspond to ______ pressure on a nearby constant- height surface.
high
Is PGF the only force affecting the winds?
No, there are additional forces affecting winds.
How are winds initiated?
PGF
Once air is in motion, two additional forces come into play which are:
- Coriolis force–Not a “real” force, but rather an effect due to observations made in a rotating reference frame
- Frictional force-A force of opposition which slows air in motion
Explain the Coriolis force
- The Coriolis force produces an apparent deflection of moving objects to the right in the Northern Hemisphere and to the left in the Southern Hemisphere
- The Coriolis force is zero at the equator and increases with increasing latitude
- The Coriolis force acting on any object increases with object’s speed
- The Coriolis force changes only the direction of the object, not its speed
Explain frictional force
A force of opposition which slows air in motion.
• Initiated at the surface.
• Important for air within 1.5 km (1 mi) of the surface (the planetary boundary layer), and negligible aloft (the free atmosphere).
• Friction reduces wind speed, so it also reduces Coriolis force.
Does friction only reduce wind speed or does it reduce wind speed and the coriolis force?
Friction reduces wind speed, so it also reduces Coriolis force.
An airplane is flying forward at constant speed. At a given moment the forces acting on the airplane are such that Thrust is balanced by Air Friction, but Lift is smaller than the Weight. How is the airplane motion going to respond?
Airplane will continue moving forward at the same speed, but will accelerate downward
What is PGF caused by?
PGF caused by differential heating of equator and poles
What is geostrophic balance?
PGF and Coriolis Force are in balance, so the wind does not change anymore!
Hydrostatic balance (in the vertical)
PGF=gravitational force