Earth Science Terms

Radiation

transmission of energy as electromagnetic waves

Positive feedback mechanism

Act to amplify a change

Negative feedback mechanism

Act to resist change

Stefan-Boltzmann Law

relates radiant energy and temperature

Wien’s displacement law

relates temperature and peak radiation wavelength

Insolation

flow rate of incoming solar radiation

solar altitude

angle of the sun above the horizon

subsolar point

point on earth’s surface where Sun is directly overhead

milankovitch cycles

cyclical changes in the shape of Earth’s orbit, direction of Earth’s tilt, and the degree of Earth’s orbit

Thermal energy

heat

Temperature

index used to measure the thermal energy of matter

Specific heat

amount of heat (energy) required to raise the temperature of 1 g of a substance by 1°C

Sensible heat

energy required to change the temperature of a substance without a phase change

Latent heat

energy gained or lost when a substance changes phase at a constant temperature.

radiation (heat transfer mechanism)

transfer of energy in electromagnetic waves through space

conduction (heat transfer mechanism)

molecule-to-molecule transfer of energy between substances

convection (heat transfer mechanism)

transfer by movement of a gas or liquid

Atmosphere

gaseous envelope surrounding Earth

albedo

proportion of incoming radiation that is reflected

terrestrial radiation

longwave radiation emitted by Earth’s surface and atmosphere

net radiation

difference between total radiation absorbed (incoming, ↓) and emitted (↑, outgoing)

atmospheric circulation

Prevailing winds, storms, etc.

ocean currents

Surface currents, Deep sea currents

weather

day-to-day state of the atmosphere

climate

Long-term (30+ years) aggregate weather over a region

gulf stream

Ocean current carrying warm water from the Gulf of Mexico northwards and across the North Atlantic

maritime effect

Large water bodies (oceans, lakes) moderate the air temperatures of nearby regions

urban heat islands

Urban areas may absorb (and emit) more heat than nearby natural surfaces

environmental lapse rate

the rate at which temperature declines with altitude at a given location

wind

movement of air relative to Earth’s surface

atmospheric pressure

weight of a column of air per unit area

isobars

lines of equal sea-level pressure

pressure gradient

difference in surface pressure divided by the distance between two locations

coriolis force

apparent force deflecting objects moving over the surface due to a rotating Earth

geostrophic winds

winds where PGF is balanced with CF, winds flow parallel to isobars, wind speed related to PGF

Surface winds

Surface winds flow across isobars, wind speed related to PGF + friction

zonal flows

parallel to lines of latitude; W-E

meridional flows

parallel to lines of longitude; N-S

intertropical convergence zone

equatorial low; thermal pressure low belt of rising air fed by converging Northeast and Southeast trade winds

polar front

Latitudinal zone (~60° N and S) where warmer westerlies are forced to rise above colder polar easterlies → semipermanent subpolar low

monsoon

seasonal reversal of windflow and pressure