GEOG 120 Exam 1 - UW Madison

system

composed individual but connected parts that function as a complex whole

closed system

not exchanging matter, energy, info with the surrounding ambient environment

open system

exchanging matter, energy, info with surrounding ambient environment

external forcings

affect a system, are not affected by it (i.e. the sun and the earth's relationship)

internal feedbacks

interlinked interactions among components within a system

feedback loops

processes interacting within systems that form looped chains of causes and events

state variables

variables that describe state of system

couplings

mechanisms linking variables, can be positive or negative

albedo

reflectivity of a surface

positive feedback loop

amplify original trend, promote instability and rapid change

negative feedback loop

counteract original trend, stabilizing

energy

the ability to do work or change the state of matter

electromagnetic radiation (emr)

vibrating electronic force fields composed of waves of varying frequency and wavelength

"shortwave" radiation

higher frequency, higher energy per photon

"longwave" radiation

lower frequency, lower energy per photon

optical band

0.4 microns - 0.7 microns, visible light spectrum

blackbodies

perfectly emit and absorb emr at all wavelengths

Wien's Law

wavelength of peak emr emitted by blackbody shortens with increasing temperatures

Stefan-Boltzman Law

amount of emitted emr by blackbody is proportional to fourth power of temperature (hotter an object gets, the more emr it emits)

sunlight reflected by albedo

30%

insolation after passage through atmosphere

- positive net radiation in low altitudes

- negative net radiation in high altitudes

atmospheric pressure

force exerted by kinetic motion of gas molecules

atmospheric density

mass per unit volume

thermal structure of atmosphere

thermosphere, mesosphere, stratosphere, troposphere

tropospheric lapse rate

rate of temperature decrease with increasing elevation

atmospheric stability

tendency of air mass to remain in place (vs. rising/falling)

atmospheric composition

- major gases: nitrogen, oxygen, argon

- minor gases: water vapor, carbon dioxide, methane, ozone

- aerosols (dust)

ozone layer

- shields us from uv radiation

- stratosphere

- destroyed by chlorine reactions

- pollutant in troposphere

emission

converts heat energy > emr

transmission

emr passes through object

absorption

converts emr > heat energy

reflection

solids/liquids; radiations if redirected in a different direction

scattering

forms of reflection; gases

earth's albedo average

31%

water albedo high angle

low albedo

water albedo low angle

high albedo

raleigh scattering

short wavelengths scatter more easily than long wavelengths (i.e. why the sky is blue)

greenhouse effect

atmosphere is (mostly) transparent to visible light and (mostly) absorptive of infared emr

clouds and energy budget

both reflect sunlight and trap outgoing long wave radiation

cloud rule of thumb

high clouds warm the earth, low clouds cool the earth

aerosols direct effect

absorb and scatter shortwave radiation

- warms atmosphere

- cools earths surface

aerosols indirect effect

nucleation sites for water droplets which leads to cloud formation

heat energy

kinetic energy of atoms; more energetic atoms move faster

sensible heat

heat energy that results in a change in temperature corresponds to the vibrational energy of molecules

latent heat

heat energy that results in a change in phase of matter

conduction

heat transfer by contact

convection

heat transfer by movement of fluid masses; primarily vertical

advection

as convection, but primarily horizontal

100 units of incoming units of

shortwave emr

20 units (of 100 incoming) absorbed by

atmosphere

31 units (of 100 incoming) reflected by

atmosphere or earths surface

49 units (of 100 incoming) absorbed by

earths surface

114 units of outgoing

longwave emr emitted by earths surface

102 units (0f 114 outgoing) absorbed by

atmosphere

69 units (of 114 outgoing) escape into

space via surface, atmosphere, and clouds

95 units (of 102 absorbed by atm.) reflected by

atmosphere back towards earth's surface

30 units of heat energy emitted

by earths surface; none is lost to space and it is collectively mixing in the atmosphere

shortwave radiation from top of atm

highest values in areas of low albedo

longwave radiation from top of atm

highest values in areas of low altitudes

annual surface losses of latent heat

warm and wet areas

annual surface losses of sensible heat

warm and dry areas

gravity

pulls air down; works opposite atmospheric pressure

buoyancy

density of an object compared to the outside density

pressure gradient force

air forced from high pressure to low pressure

pressure gradients and wind

strongest winds in areas of steep pressure gradient

Coriolis force

- acts perpendicular to the direction of travel; deflects moving objects

- results from: earth's rotation and conservation of momentum

- strength of this force is proportional to velocity of moving object (i.e. high velocity, high force)

northern hemisphere (Coriolis)

deflected to the right

Southern Hemisphere (Coriolis)

deflected to the left

vorticity

local spinning motion of a fluid

high at the poles and zero at the equator

friction

force of friction acts opposite to the direction of travel; it slows objects

vapor pressure

pressure exerted by water vapor

Clausius-Clapeyron equation

an equation that displays the exponential relationship between vapor pressure and temperature

saturation vapor pressure

maximum capacity of air to hold water vapor. if this is exceeded, water will condense from vapor to liquid

relative humidity

water vapor pressure relate to saturation vapor pressure (%)

specific humidity

water vapor mass relative to total air mass (g H2O / kg air)

dew point

temperature at which air of given water vapor pressure becomes saturated

dew point and clouds

cloud formation occurs once an air mass passes its dew point. Can occur by adding moisture or cooling air.

atmospheric stability

tendency of air paced to remain in place (stable) or rise upwards (unstable)

two opposing forces of stability

gravity (downward) and buoyancy (upward)

air mass destabilization

warming or adding moisture to an air mass tends to destabilize it

adiabatic processes

processes that occur with no net heat exchange between a parcel of air and the environment