AES 104 terms

For AES 104 with Professor Vivian Brasfield at UAH

Anthropogenic climate change

human-caused climate change

The Atmosphere

A mixture of gas, liquid and solid particles, and falling precipitation

Weather

The state of the atmosphere at a given place and time, short term phenomena

Meteorology

Study of the atmosphere and the processes that cause weather

Climate

The average condition of the atmosphere (such as temp or precipitation) over a long period of time. Long term patterns.

Climatology

Long-term study of the atmosphere and processes that cause climate

Minimum climatology study period

30 years

Precipitation

All forms of moisture falling to the surface of the Earth (rain, snow, sleet, etc.)

Temperature

How warm or cool the air is outside

Climographs

A graph that often shows precipitation, temperature, and time of year for a specific location

atmospheric composition

• Nitrogen 78%

• Oxygen 21%

• Carbon dioxide 0.035%

• Argon 0.9%

• Other gases 

Atmospheric Pressure

pressure=force/area

Density

Mass (kg) per unit volume (m^3)

Standard atmospheric pressure at sea level

• 1013.25 millibars (mb)

• 1013.25 hectoPascals (hPa)

• 29.92 inches of Mercury (in of Hg)

Temperature (science-y)

Measure of average kinetic energy of individual molecules in matter

Conversion between Fahrenheit and Celsius

F= 9/5(C)+32

Conversion between Kelvin and Celcius

K=C+273.15

Layers of the atmosphere

Troposphere, Stratosphere, Mesosphere, Thermosphere/Exosphere

What causes Planetary/Global winds?

well defined pressure patterns on Earth define global wind patterns

Zonal Winds

Winds that move in an east-west direction

Meridional Winds

winds that move in a north-south direction

Single cell model

A wind movement model by George Hadley, that explains wind patterns with Hadley Cells

Thermally-direct circulation

circulation of air from expansion and contraction caused by changes in temperature

Three cell model

A more accurate, but still idealized model of wind movement that divides hemispheres into a Hadley Cell, a Ferrel Cell, and a Polar Cell

Thermally Indirect Circulation

movement of air that is driven dynamically, with friction, like gears turning

Easterlies

Winds blowing from the east

Westerlies/Prevailing Westerlies

winds blowing from the west

ITCZ

Intertropical Convergence Zone, a low pressure band around the Equator

Horse Lattitudes

the latitudes about 30 degrees north and south of the Equator

Trade winds

easterlies

Doldrums

an Equatorial region of the Atlantic with calms, sudden storms, and light unpredictable winds. Where the trades of the Northern and Southern hemispheres collide.

Polar Easterlies

the dry, cold winds that blow around the high-pressure of the polar highs at the North and South poles.

Polar Front

the weather front boundary between the polar and ferrel cell around 60 degrees lattitude. At this boundary a sharp temp gradient occurs between the two air masses.

Polar Vortex

a large region of cold, rotating air. They encircle both of Earth’s poles.

Subtropical Jet

air converging between Hadley and Ferrel cells

Polar Jet

air converging between Polar and Ferrel cells

Semi Permanent Pressure Cells

pressure cell that may fluctuate seasonally and may be thermal or dynamic

Air Pressure

Force per unit area exerted against a surface by the weight of air above the surface.

980mb

Anything below this pressure is a Low Pressure system.

Isobars

Lines of Equal pressure.

Pressure gradient

depict the rate of change in pressure over a distance.

Pressure gradient force

the force exerted by air flowing from high pressure to low pressure areas.

Coriolis Force

deflection of large non-tethered objects cause by the rotation of the Earth

Coriolis Deflection In Northern Hemisphere

Westerly flow deflects to South, Easterly flow deflects to the North

Coriolis Deflection In Southern Hemisphere

Westerly flow deflects to North, Easterly flow deflects to South

Upper Air Flow

Air flow about 2 km above surface

Geostrophic wind

The wind resulting from the balance of Coriolis Force and PGF

Centripetal Acceleration

For a circular path at uniform speed, centripetal acceleration is the radially inward-directed acceleration of something

Cyclonic Flow

Circular flow around a low-pressure center. In NH, flow is counter-clockwise.

Anti-cyclonic Flow

Circular flow around a high-pressure center. In NH, flow is clockwise.

Trough axis 

Has rising air ahead, sinking air behind, and winds slower than geostrophic

Ridge Axis

Has sinking air ahead, rising air behind, has winds faster than geostrophic

Wind direction

the direction the wind is flowing from

Azimuth

the degree of the angle the wind is blowing from

Wind vanes

tool that indicates wind direction

Anemometers

tool that can record wind speed

Aerovanes

tool that can measure wind speed and direction

The Weather Station Model

Heat Transfer Mechanisms

Conduction, Convection, and Radiation

Conduction

Heat transfer between things that are touching molecules, most effective in solid materials

Convection

Transfer of energy by mixing a fluid or gas

Radiation

Transfer of radiation that requires no physical medium (can occur in empty space)

Radiation Quality

the wavelength of radiation

Radiation Quantity

Refers to amount of energy being transferred, associated with wave amplitude

amplitude

wave height

Electromagnetic Spectrum (EM)

Wavelength of radiation categorized into a few individual “bands” along the electromagnetic spectrum

shortwave radiation

Wavelengths less than 4 microns, also called visible radiation

longwave radiation

Wavelengths longer than 4 microns, also considered infrared

Earth/Terrestrial radiation

Radiation emitted by the surface of the earth

Insolation

Incoming Solar Radiation

Atmospheric Influences on Insolation

Absorption, Reflection/scattering, Transmission

Absorption

Energy transfer to an absorber, which gains heat energy and warms. Once it warms, it will emit longwave radiation as heat.

Reflection and scattering

Energy redirected by objects without energy being absorbed via reflection.

Transmission

The percentage of energy transmitted through the atmosphere to the surface.  Is dependent on the atmosphere’s ability to absorb, scatter, and reflect

Specular reflection

Radiation is reflected back as a beam of equal intensity

Diffuse reflection, or scattering

Radiation is reflected as dispersed energy in a larger number of weaker rays going in many directions

Albedo

 the percentage of energy reflected by an object

Rayleigh Scattering

It involves gases smaller than the incoming solar radiation wavelength, and air molecules scatter radiation via diffuse reflection. Makes the sky blue.

Mie Scattering

Scattering by dust, haze, aerosols. It has forward scattering and is equally effective across the color spectrum.

Non-Selective Scattering

Happens when atmospheric particles are much larger than the wavelength of incoming radiation. All colors are scattered equally. makes clouds white.

Greenhouse Gases (GHG)

Gases that are efficient in absorbing infrared (IR) radiation

Free Convection

Mixing related to buoyancy. Warmer, less dense fluids and gases rise

Forced Convection

Mixing initiated by eddies and other disruptions. Smooth uniform flow, associated with higher wind speeds

sensible heat

temperature changing that we can physically sense.

specific heat

the amount of energy required to produce a temperature change per unit mass

laminar boundary layer

layer where the flow takes place in layers, i.e., each layer slides past the adjacent layers.

turbulent boundary layer

occurs when smooth laminar flow breaks down and transitions to flow with eddies.

Latent Heat

no felt/experience change in temperature. Energy required to change phase (solid, liquid, gas) of substance

Isoheights

Lines of same height

Isotherms

Lines of equal temperature

Altitude

the difference in sea level height

elevation

difference in height above ground level

Influences on Temperature

Lattitude, Altitude/Elevation, Atmospheric Circulations, Contrasts between Land/Water, Warm/cool ocean currents, and Local Conditions

advection

transport of something via wind

Continentality

the effect of inland location that favors greater temperature extremes

Warm currents

Currents that move poleward from the equator in the western portion of the ocean basin. Found near the east coasts of continents in mid-latitudes.

Cool currents

Currents that move toward the equator in the eastern portion of ocean basins. It causes moderate west coast temps in mid-latitudes.

Adiabatic

no heat exchange, no heat release

Dewpoint

The temperature at which condensation occurs

(depends on humidity). It is always equal to or less than the air Temperature

Relative humidity (RH)

How close the air is to being saturated.