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Atmospheric Enviroment Midterm 1


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the condition of the atmosphere at a particular time in terms of temperature, moisture, wind, and pressure__meteorology is the study of weather.
the long-term (many year) condition of the atmosphere at a particular location including averages and extremes__climatology is the study of climate.
tends to pull particles towards the earth's surface
cause particles to move from areas of high to low concentration
Weather (large-scale circulation)
causes gases/particles to mix
chemical change, changes of state
Which is heavier? Dry air or moist air? Why?
Dry air; because Avogadro's Law states that there is constant number of molecules in a given volume of gas.
General Atomic Masses
N2, 28; O2, 32; H2O, 18.
mechanism that supplies a gas to the atmosphere.
mechanism that removes a gas from the atmosphere.
Hydrologic Cycle
Water is first evaporated from the ocean to aid in condensation and formation of clouds. Then, precipitation occurs, raining the water onto forrest life and river flow, where transpiration takes place. It then starts from the beginning.
Atmospheric Pressure (measured in)
101.3 kPa, 1013mb, 14.6 psi, 29.92 in of mercury
Ideal Gas Law
As pressure increases--tempreature increases (air heats as it sinks, cools as it rises)
As temperature increases--density decreaes.
As density decreases--volume increases (air expands and rises as it is heated).
wind speed
Parcel of air
mass of air of any arbitrary size and shape that has uniform characteristics in terms of pressure, temp, humidity, etc.
Kinetic Energy

Potential Energy
work done by a body as a result of its motion.

work that can be done by a body as a result of its position.
average kinetic energy of the molecules in a substance
total kinetic energy of the molecules in a substance
Specific Heat
the amount of energy required to raise the temperature of one gram of substance by 1 degree Celsius
rate of transfer of energy. One Watt (W) = 1Joule/sec
Heat Energy Transfer
Forms of Heat
Sensible Heat: experienced as a temperature change that would register on a thermometer

Latent Heat: heat absorbed or released as water changes state
Adiabatic Warming/Cooling
temperature change with no actual gain or loss of heat energy
Interaction of Radiation with Objects
Absorption: energy transfrered to object
Reflection: energy sent back
Transmission: energy passes through with little interaction
The Greenhouse Effect
absorption of longwave radiation from the Earth's surface by certain gases in the atmosphere
Surface Temperature
air temperature in the shade, meausured 1.5m above the ground
Earth's Surface Temperature
Mean global surface temp: 59 degrees Fahrenheit
Factors Affecting Temperature Cycles
surface type
elevation and aspect
effect of large bodies of water
cloud cover
more extreme temperature ranges at higher latitudes
Surface Type
surfaces store and reradiate energy back to the atmosphere:
increas. vegetation-decreasing temp
increas. moisture-decreasing temp
increas. specific heat of surface materials-decreasing temp
Neutral Atmosphere
if a parcel of air is released and sinks, it is stable. Conversely, if it rises, it is unstable
Valley Inversions
air near ground cools, cold air will drain down hills creating a cold pool of air
Factors Affecting the Rate of Evaporation
temperature, wind, antecedent humidity
Vapor Pressure
portion of atmospheric pressure provided by water vapor (0-4 kPa)
Relative Humidity
100% (vapor pressure / saturation vapor pressure)...
the amount of vapor actuallyin the air, relative to the amount of vapor the air could hold
Dew Point
the temperature to which the air must be cooled to become saturated (without changing the pressure)
Cloud Formation
nucleation, condensation, and deposition of vapor into cloud droplets and ice crystals
(almost always?)
Homogeneous: water droplet serves as condensation nucleus
Heterogeneous: small, non-water, particles serve as condensation nuclei
Hydrophobic Nuclei
resist condensation, but may serve as nuclei as RH approaches 100%
Hygroscopic Nuclei
attract water droplets, and may serve as nuclei even when RH < 100%, due to the solute effect
The greater the quanity of molecules, the greater the chance of initial crystal formation--therefore, very small drops take more time/lower temp to freeze
Advection Fog
movement of warm air over cooler surface
Radiation Fog
forms when land surface cools as a result of outgoing radiation and in turn, cools over lying air
Upslope Fog
forms when adiabatic processes cool air as it moves upslope
Steam Fog (evaporation)
forms when cold air moves over warm water
high altitude
mid altitude
precipitation that evaporates before reaching the ground
Do clouds cool the planet, or warm it?
Both. Clouds absorb longwave radiation from below, and also reflect solar radiation. Additionally, they emit longwave radiation in all directions
angle of incidence = angle of refelction of a surface
when the light ray bends toward the normal when entering the water
the change of direction of light rays when they encounter foreign particles
seperation of light into its component wavelengths
the bending of light around small particles
Why is the sky blue?
white light comes directly from the sun, so the blue appearing is from scattered light coming from the sun
Why are sunsets orange/red?
molecules scatter and dust reflects the sunlight. also, light from the sky near the sun automatically appears red, not to mention the light coming directly from the sun.
Automated Surface Observing System (ASOS)
measures cloud height, visibility, pressure, precipitation, wind velocity, temperature, and dew point at hundreds of nationwide locations
measures the temperature difference between a wet and dry bulb thermometer
Radar Sensor
active sensors that emit radio waves and measure their return
Doppler Radar
measures velocity of particles through the resultant frequency shift
distance traveled in a given time
speed and direction of motion
change in velocity in a given amount of time
Wind Direction
compass direction from which the wind is blowing
compass direction or side from which the wind blows
compass direction or side toward which the wind blows
low pressure system associated with counterclockwise wind circulation
high pressure system associated with clockwise wind cirulation
Prevailing Wind Direction
direction from which the wind most often blows
Wind Gusts
variations in wind speed above the mean
Newton's First Law of Inertia
objects in a state of uniform motion (including rest) remain in that state of motion unless acted upon by an external force
Newton's Second Law of Momentum
the relationship between an objet's mass m, its acceleration a, and the applied force F, is F=ma.
The momentum of an object (p) is equal to its mass multiplied by its velocity: p=mV
Gravitational Force
g=9.81, M=mass
Pressure Gradient Force (PGF)
change in pressure over a specified distance
Coriolis Force
causes an apparent change in direction of anything on earth moving with repect to the ground.
caused by the fact that moving objects carry with them the momentum they aquired from the rotating earth at their previous latitude
Frictional Force (FF)
force that opposes motion. with respect to wind, it results from the roughness of the Earth's surface
Buys Ballot's Law
low pressure is always on the left of the wind (in Northern Hemisphere)

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