Weather and Climate

humidity

water vapor content of the atmosphere

pressure

amount of force exerted by molecules; force per unit area

velocity

speed in a given direction

acceleration

change in velocity over time

speed

change in distance over time

force

mass times acceleration

weight

downward force exerted by mass under acceleration of gravity

energy

ability to do work

1013.25 mb

global average air pressure at sea level

outgassing

gases released by volcanic eruptions; led to secondary atmosphere of earth

permanent gases

gases with constant proportion in the atmosphere

78%

concentration of nitrogen in atmosphere

21%

concentration of oxygen in atmosphere

variable gases

gases that do not have a constant proportion in the atmosphere and are of a small percentage but that still impact the atmosphere’s behavior

aerosol

tiny suspended solid or liquid particles in the air

troposphere

lowest ~10km of the atmosphere

normal environmental lapse rate

rate by which air temperature decreases in temperature with increasing height in troposphere

3.6F per 1000 feet

numerical value of normal environmental lapse rate

tropopause

upper boundary of the troposphere

temperature inversion

where temperature increases with increasing altitude

25 miles

height at which ozone is most concentrated

homosphere

well-mixed region of atmosphere with uniform composition (N2, O2, etc) due to turbulent mixing; where weather occurs

Heterosphere

vertical portion of the atmosphere where gases are layered by atomic weight and less mixing occurs

ionosphere

upper mesosphere through the thermosphere; electrified region with large concentrations of ions and free electrons; filters harmful wavelengths of solar radiation

temperature

measure of heat energy

conduction

mechanism of heat transfer through molecular activity

convection

mechanism of heat transfer through movement

radiation

mechanism of heat transfer in the form of electromagnetic energy

insolation

incoming solar radiation

albedo

percent energy reflected; affects incoming radiation

perihelion

January 3, the date on which the earth is closest to the sun

aphelion

July 4, day earth is furthest from sun

23.5

number of degrees by which earth’s axis is tilted

June 21/22

date on which the sun’s rays are directly over 23.5 degrees north

Tropic of cancer

23.5 degrees north

September 22/23

day on which sun is directly located at the equator in autumn

December 21/22

day on which sun is directly above 23.5 degrees south

tropic of capricorn

23.5 degrees south

March 21/22

spring equinox on which sun’s rays are located at the equator

solar altitude or sun angle

angular distance between the horizon and the sun

solar declination

latitude receiving direct rays of solar energy on a given day

zenith angle

angle between a point directly overhead and the sun at solar noon

specific heat

amount of heat required to raise the temperature of 1g of a substance one degree Celsius

calorie

amount of energy required to raise one gram of water by one degree Celsius

isotherm

a line connecting places of equal temperature on a map

latent heat

[find def in textbook]

evaporation

change in state of water from liquid to gas

600 cal./g

energy absorbed by evaporation

600 cal./g

energy released by condensation

condensation

change in state of water from gas to liquid

melting

change in state of water from solid to liquid

80 cal./g

amount of heat energy absorbed by melting

freezing

change in state of water from liquid to solid

80 cal./g

amount of heat energy released by freezing

sublimation

change in state of water from solid to gas

680 cal./g

amount of latent heat absorbed by sublimation

deposition

change in state of water from gas to solid

680 cal./g

the amount of latent heat released from deposition

saturation

[find def in text]

air parcel

[find def in text]

absolute humidity

mass of water vapor/volume of air (g/m³)

specific humidity

mass of water vapor/total mass of air (including vapor); (g/kg)

mixing ratio

mass of water vapor/mass of dry air (g/kg)

actual vapor pressure

partial pressure of water vapor in a given air parcel

saturation vapor pressure

partial pressure that vapor would exert if the parcel were saturated at a given temperature

relative humidity

ratio of content/capacity; for example actual vapor pressure/saturation vapor pressure