Standard 6.6 The student will investigate and understand the properties of air and the structure and dynamics of the Earth’s atmosphere. Key

concepts include

air as a mixture of gaseous elements and compounds;

air pressure, temperature, and humidity;

how the atmosphere changes with altitude;

natural and human-caused changes to the atmosphere;

the relationship of atmospheric measures and weather conditions;

basic information from weather maps including fronts, systems, and basic measurements; and

the importance of protecting and maintaining air quality.

Essential Knowledge, Skills, and Processes

In order to meet this standard, it is expected that students should be able to:

comprehend and apply basic terminology related to air and the atmosphere.

identify the composition and physical characteristics of the atmosphere.

analyze and interpret charts and graphs of the atmosphere in terms of temperature and

pressure.

measure and record air temperature, air pressure, and humidity in using appropriate units

of measurement and tools.

analyze and explain some of the effects that natural events and human activities may have

on weather, atmosphere, and climate.

map the movement of cold and warm fronts, and interpret their effects on observable

weather conditions.

design an investigation to relate temperature, barometric pressure, and humidity to

changing weather conditions.

interpret basic weather maps, and make forecasts based on the information

presented.

compare and contrast cloud types, and relate cloud types to weather

conditions.

compare and contrast types of precipitation.

compare and contrast weather-related phenomena including thunderstorms,

tornados, hurricanes, and drought.

evaluate their own roles in protecting air quality.

Earth’s Atmoshere is a blanket of gases.The earth's atmosphere as viewed from space. The thin blue area near the horizon shows the shallowness of the earth's atmosphere.

At the surface, there is a balance between destruction (output) and production (input) of these gases. For example, nitrogen is removed from the atmosphere primarily by bio-logical processes that involve soil bacteria. It is returned to the atmosphere mainly through the decaying of plant and animal matter. Oxygen, on the other hand, is removed from the atmo-sphere when organic matter decays and when oxygen com-bines with other substances, producing oxides. It is also taken from the atmosphere during breathing, as the lungs take in oxygen and release carbon dioxide (CO2). The addition of oxygen to the atmosphere occurs during photosynthesis, as plants, in the presence of sunlight, combine carbon dioxide and water to produce sugar and oxygen.

The concentration of the invisible gas water vapor (H20), however, varies greatly from place to place, and from time to time. Close to the surface in warm, steamy, tropical locations, water vapor may account for up to 4 percent of the atmospheric gases, whereas in colder arctic areas, its concen-tration may dwindle to a mere fraction of a percent (see Table

1.1). Water vapor molecules are, of course, invisible. They become visible only when they transform into larger liquid or solid particles, such as cloud droplets and ice crystals. The changing of water vapor into liquid water is called condensa-tion, whereas the process of liquid water becoming water vapor is called evaporation. In the lower atmosphere, water is everywhere. It is the only substance that exists as a gas, a liquid, and a solid at those temperatures and pressures nor-mally found near the earth's surface (see Fig. 1.3).

Water vapor is an extremely important gas in our atmo-sphere. Not only does it form into both liquid and solid cloud particles that grow in size and fall to earth as precipitation, but it also releases large amounts of heat—called latent heat— when it changes from vapor into liquid water or ice. Latent heat is an important source of atmospheric energy, especially for storms, such as thunderstorms and hurricanes. Moreover, water vapor is a potent greenhouse gas because it strongly absorbs a portion of the earth's outgoing radiant energy (somewhat like the glass of a greenhouse prevents the heat

TABLE 1.1 Composition of the Atmosphere Near the Earth's Surface

PERMANENT GASES

s - Percent (by Volume) Percent Parts per

Gas Symbol Dry Air Gas (and Particles) Symbol (by Volume) Million (ppm)*

Nitrogen N2 78.08 Water vapor H2O 0 to 4

Oxygen O2 20.95 Carbon dioxide CO2 0.036 365*

Argon Ar 0.93 Methane CH4 0.00017 1.7

Neon Ne 0.0018 Nitrous oxide N2O 0.00003 0.3

Helium He 0.0005 Ozone O3 0.000004 0.04**

Hydrogen H2 0.00006 Particles (dust, soot, etc.) 0.000001 0.01-0.15

Xenon Xe 0.000009 Chlorofluorocarbons (CFCs) 0.00000002 0.0002

*For CO,, 365 parts per million means that out of every million air molecules, 365 are CO, molecules.

"Stratospheric values are about 5 to 12 ppm.

VARIABLE GASES

http://www.srh.noaa.gov/jetstream/atmos/layers.htm very nice general site

for info

The layers of the atmosphere are determined by TEMPERATURE TRENDS. As you rise through the Troposphere, the temp falls. This temp drop is about 6.5 degree C. drop for every 1000 m.(1km). That is about 40 F. per 1000 feet. Somewhere around 12 km (7mi) up the temp trends higher so we have left the Troposphere and entered the next layer, Stratosphere.

In the Troposphere we find all of our weather. Weather is caused by the UNEVEN HEATING of the Earth’s surface. Also largely involved is the water cycle.

Evaporation, Transpiration, Condensation,

Precipitation

ATMOSPHERE

TROPOSPHERE -from Greek tropos means “turning” or “mixing” -lowest portion of Earth’s atomosphere….zero to 10 km up At the equator it is around 11-12 miles (18-20 km) high, at 50°N and 50°S, 5½ miles and at the poles just under four miles high. -contains approximately 75% of atmosphere’s mass -averages about 11 km thick (depth) /starts at Earth and goes up to around 7 miles -closest layer is influenced with friction of Earth’s surface changing air flow

-all of our weather is here….clouds, storms, hurricanes, etc.

-chemical composition mostly uniform ….except for water vapor -temperature decreases with height -water vapor decreases with temp drop so water vapor decreases with height

STRATOSPHERE -second layer of Earth’s atmosphere ….10km to 50 km /up to around 31 miles

-stratified by layers….colder lower going warmer as you climb higher

-top level of this layer has a temp of approx. –3oC (just below freezing) -temp heated by UV radiation and increases with height -jets climbs to here to use the Jet Stream advantages -the ozone layer is found here. Protects us from harmful UV radiation. -weather balloons can reach this layer Stratosphere holds around 24% of all atmospheric mass

Troposphere plus Stratosphere combine for 99% of atmosphere’s mass

MESOSPHERE -from Greek mesos=middle, and sphaira=ball -50 km to about 80-90 km above earth

-temperature decreases with altitude in this layer

-this layer is between maximum altitude for aircraft and minimum altitude for spacecraft -most poorly understood part of our atmosphere

-meteors burn up here due to increasing molecules closer to Earth

THERMOSPHERE -from Greek word for heat

-largest layer of our atmosphere, above mesosphere and below exosphere

-starts about 90 km above earth and up to about 500-1000 km above earth (or outer space)

-temperatures rise with altitude here rising to as much as 1500 C.

-you would not feel this heat as heat is transferred between particles and there are extremely few particles in the Thermosphere. A normal thermometer would read well below 0 C. due to the near vacuum of particles found here. -temperature is highly dependent on solar activity at this point -radiation here causes atmospheric particles here to become electrically charged (ionosphere) allowing radio waves to “bounce off” this layer

-space shuttle and International Space Station orbit here http://www.windows2universe.org/earth/Atmosphere/thermosphere.html

Temperatures climb sharply in the lower thermosphere (below 200 to 300 km altitude), then level off and hold fairly steady with increasing altitude above that height. Solar activity strongly influences temperature in the thermosphere. The thermosphere is typically about 200° C (360° F) hotter in the daytime than at night, and roughly 500° C (900° F) hotter when the Sun is very active than at other times. Temperatures in the upper thermosphere can range from about 500° C (932° F) to 2,000° C (3,632° F) or higher.

Finally, the aurora (the Southern and Northern Lights) primarily occur in the thermosphere. Charged particles (electrons, protons, and other ions) from space collide with atoms and molecules in the thermosphere at high latitudes, exciting them into higher energy states. Those atoms and molecules shed this excess energy by emitting photons of light, which we see as colorful auroral displays.

The Ionosphere Scientists call the ionosphere an extension of the thermosphere. So technically, the ionosphere is not another atmospheric layer. The ionosphere represents less than 0.1% of the total mass of the Earth's atmosphere. Even though it is such a small part, it is extremely important!

The upper atmosphere is ionized by solar radiation. That means the Sun's energy is so strong at this level, that it breaks apart molecules. So there ends up being electrons floating around and molecules which have lost or gained electrons. When the Sun is active, more and more ionization happens!

Different regions of the ionosphere make long distance radio communication possible by reflecting the radio waves back to Earth.

http://www.srh.noaa.gov/jetstream/atmos/ionosphere_max.htm

The Earth’s ionosphere and ground form a “waveguide” through which VLF radio signals can propagate or “bounce” around the Earth. Image courtesy Morris Cohen, Stanford University

EXOSPHERE -often considered part of the thermosphere -the outermost layer of earth’s atmosphere. Very, very few particles are in this layer -particles here can actually reach “escape velocity” and leave this layer’s weak gravitational pull. -this layer begins around 500-1000 km up and tails off into outer space

-repeat; there are almost no atoms or particles here. The lightest atoms are found here

such as hydrogen, helium, carbon dioxide and atomic oxygen.

Aurora Borealis An aurora (plural: auroras or aurorae) is a natural light display in the sky particularly in the high latitude (Arctic and Antarctic) regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere (thermosphere). The charged particles originate in the magnetosphere and solar wind and, on Earth, are directed by the Earth's magnetic field into the atmosphere. Aurora is classified as diffuse or discrete aurora.

Its southern counterpart, the aurora australis (or the southern lights), has almost identical features to the aurora borealis and changes simultaneously with changes in the northern auroral zone and is visible from high southern latitudes in Antarctica, South America and Australia.

Sweden

http://www.gi.alaska.edu/AuroraForecast Interesting site for aurora info and schedules

http://roble.pntic.mec.es/rmac0040/watercycle.html

http://kilby.sac.on.ca/faculty/dgalajda/enviro/atmosphere.htm

http://www.srh.noaa.gov/jetstream/atmos/atmprofile.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/pman.html#bar (barometric pressure illustration/explain

http://www.kidsgeo.com/geography-for-kids/0048-temperature-effects-on-atmosphere.php (temp chart)