Heating the Atmosphere

Composition, Structure and Temperature

Temperature vs. Heat

Heat  - The thermal energy of atoms or molecules that make up any  piece of matter are constantly in motion.  Heat is the energy that flows because of temperature differences.

Temperature – a direct quantitative measure of this internal motion.

The higher an objects temperature, the faster the random motion of its particles.

Weather vs. Climate

Weather is the state of the atmosphere at any given point in time or place.

Climate is the general state of the atmosphere over time for a given location.

Milankovitch Cycles

http://users.aber.ac.uk/dcb4/milankovitch%20cycles.jpg

For world weather info go to

http://www.cnn.com/WEATHER/

What factors affect the earth’s temperature, both locally and globally?

Local factors include 

1. latitude

2. proximity to water

3. topography

4. elevation

5. prevailing winds 

6. proximity to cold or warm ocean currents

7. albedo

8. cloud coverage

Global factors include 

1. earth's position relative to the sun

2. amount of greenhouse gases (Carbon Dioxide and Water Vapor have the greatest effect on climate and weather)

3. energy level of global currents

This site describes heat transfer

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

Compare and contrast the mechanisms of heat transfer.

Heat Transfer

    Heat is continually redistributed through the earth/atmosphere system.

Radiation waves can travel through solids, liquids, gases or the vacuum of space. 

The earth gains or loses energy from the sun through radiation. All objects absorb and emit radiation. If an object absorbs more radiation than it emits, its temperature rises. (Think of your steering wheel on a hot day vs a cold day.)

Conduction occurs in solids, liquids and gases. Heat is transferred through the collision of neighboring atoms or molecules. Solids are generally better conductors than liquids which are better conductors than gases. Many metals are good conductors.  Air is a great insulator. Down comforters are so effective because they have trapped air which slows down the flow of heat.

Convection occurs only in fluids (liquids and gases). Differences in density cause cold fluids to sink. The sinking air pushes the warmer air up.

http://www.mansfieldct.org/schools/mms/staff/hand/convcondrad.htm

What are some causes, effects and possible solutions for global warming and ozone depletion?

http://www.science.gmu.edu/~zli/ghe.html

http://sciencecourseware.com/eec/GlobalWarming/

Global Warming and the Greenhouse Effect

    As solar radiation bombards the earth's surface, the surface heats up and releases infrared heat. This heat rises from the surface toward the atmosphere. Greenhouses gases such as water vapor, carbon dioxide and methane may block the radiant heat by either absorbing it or reflecting it back toward the surface. As this happens, the earth's atmosphere heats up.

The Greenhouse Effect is a naturally occurring event that keeps the earth warm and toasty. 

Without it, the earth's average surface temperature would be 0^o F. 

Many scientists are concerned however that fossil fuels are adding too many greenhouse gases to the atmosphere, causing the earth to overheat. 

http://www.epa.gov/globalwarming/climate/index.html

http://www.ngdc.noaa.gov/paleo/globalwarming/what.html

http://encarta.msn.com/find/Concise.asp?ti=03CCE000#s2

Overview of climate change research

http://www.exploratorium.edu/climate/index.html

faq from the intergovernmental panel on climate change

http://www.gcrio.org/ipcc/ar4/wg1/faq/index.htm

National Snow and Ice Data Center - Temp changes and latitudes

http://nsidc.org/sotc/intro.html

Ozone - the good, the bad and the ugly.

    Ozone is a relatively unstable molecule found in the earth's atmosphere. Most ozone is concentrated below 50 km (30 miles). Although it represents only a tiny fraction of the atmosphere, ozone is crucial for life on Earth.

    Depending on where ozone resides it can protect or harm life on Earth.  The amounts of good and bad ozone in the atmosphere depend on a balance between processes that create ozone and those that destroy it. An upset in the ozone balance can have serious consequences for life on earth. 

The Good Ozone

ozone tutorial

http://outreach.physics.utah.edu/labs/ozone/ozone_main.html

http://www.usatoday.com/tech/news/2004-01-08-nova-gamma-death_x.htm

Stratospheric ozone acts as a shield to protect the earth from the sun's harmful radiation. Without this shield we would be more susceptible to skin cancer, cataracts, and impaired immune systems. 

    In the stratosphere, ozone is created or destroyed primarily by ultraviolet radiation. The air is bombarded continuously with this radiation from the sun. When high-energy ultraviolet rays strike molecules of ordinary oxygen, they split the molecule into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with an oxygen molecule (O₂) to form a molecule of ozone (O₃).

    Human activities are destroying the ozone balance. Chemicals that contain chlorine (CFC) are stable in the lower atmosphere. Ultraviolet radiation in the stratosphere breaks them down. The chlorine is released. It combines with an ozone molecule to make diatomic oxygen and chlorine monoxide. If another free oxygen atom collides with the chlorine monoxide it frees the chlorine and makes another molecule of diatomic oxygen.

http://www.epa.gov/ozone/science/process.html

http://www.atm.ch.cam.ac.uk/tour/

press release 2006

http://ozonewatch.gsfc.nasa.gov/

http://jwocky.gsfc.nasa.gov/ozone/today_v8.html

The Bad Ozone  

    Ground level ozone forms when nitrogen oxides from vehicles and power plants react with volatile organic compounds from plants, paints, solvents, vehicles, refineries and factories and sunlight. Many cities, like Atlanta, have been in violation of federal standards for 20 years. Stagnant hot summer weather concentrates this problem

Ground level ozone has been linked to increased respiratory infections, and lung disease.

From USA Today by Traci Watson, 11-17-04

Public health officials have long known that breathing smog damages human airways, worsens asthma and leads to a higher risk of lung diseases such as pneumonia.

Smog, which is formed from chemicals emitted by vehicles and power plants, is the nation's most widespread air-quality problem.

The EPA announced in April that more than 450 of the nation's 3,141 counties don't meet the federal government's smog goal. Those counties are home to nearly 160 million people — more than half the U.S. population.

The other common form of dirty air that damages health is particle pollution, which exceeds federal standards in about 100 counties.

The Ugly Ozone

    If you have ever visited Atlanta, Houston or Los Angeles on a warm summer day, you may have noticed a brown haze capping the horizon. Ozone and other pollutants form this photochemical smog. 

Smog is a chemical mixture of gases that forms a brownish-yellow haze primarily over urban areas.  Components of smog include ground- level ozone, nitrogen oxides (NOx), volatile organic compounds (VOC), sulfur dioxide, and aerosols.

 These gases result from a reaction between certain airborne pollutants and strong sunlight.  Smog is most prevalent in the summer months, when there is the most sunlight and temperatures are the highest.  In large enough quantities, it poses threats to animal, plant, and human life.  The airborne pollutant which makes up 90% of all smog found in urban areas is ground level ozone.

List the major and variable components of air.

Modified from

http://liftoff.msfc.nasa.gov/academy/space/atmosphere.html

Composition of the Atmosphere

This site describes the composition of the atmosphere

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

The atmosphere is primarily composed of Nitrogen (N₂, 78%), Oxygen (O₂, 21%), and Argon (Ar, 1%). A myriad of other very influential components are also present which include the water (H₂O, 0 - 7%), "greenhouse" gases or Ozone (O , 0 - 0.01%), Carbon Dioxide (CO₂, 0.01-0.1%)

Variable Components of Air

Water Vapor – varies from 0 to 4% by volume

Aerosols – Suspended solid and liquid particles (sea salts, silt, clay, soot, smoke, pollen, microorganisms)

Ozone – 1 part in 100 million at ground level, uneven distribution

Describe the extent and structure of the atmosphere.

Temperature Scale Conversion

http://ww2010.atmos.uiuc.edu/(Gh)/guides/maps/ctof.rxml

http://ww2010.atmos.uiuc.edu/(Gh)/guides/maps/home.rxml

Upper atmosphere data for selected cities including Jax

http://weather.cod.edu/analysis/analysis.raob.html

http://raob.fsl.noaa.gov/

Earth's Atmosphere

This site describes layers of the atmosphere

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

http://www.windows.ucar.edu/tour/link=/earth/Atmosphere/layers.html

http://www.srh.weather.gov/srh/jetstream/atmos/layers.htm

 

The Earth is surrounded by a blanket of air, which we call the atmosphere. It reaches over 560 kilometers (348 miles) from the surface of the Earth, so we are only able to see what occurs fairly close to the ground.

Life on Earth is supported by the atmosphere, solar energy, and our planet's magnetic fields. The atmosphere absorbs the energy from the Sun, recycles water and other chemicals, and works with the electrical and magnetic forces to provide a moderate climate. The atmosphere also protects us from high-energy radiation and the frigid vacuum of space.

The envelope of gas surrounding the Earth changes from the ground up. Four distinct layers have been identified using thermal characteristics (temperature changes), chemical composition, movement, and density.

Troposphere

The troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). This part of the atmosphere is the most dense. As you climb higher in this layer, the temperature drops from about 17 to -52 degrees Celsius. Almost all weather is in this region. The tropopause separates the troposphere from the next layer. The tropopause and the troposphere are known as the lower atmosphere.

Stratosphere

The stratosphere starts just above the troposphere and extends to 50 kilometers (31 miles) high. Compared to the troposphere, this part of the atmosphere is dry and less dense. The temperature in this region increases gradually to -3 degrees Celsius, due to the absorbtion of ultraviolet radiation. The ozone layer, which absorbs and scatters the solar ultraviolet radiation, is in this layer. Ninety-nine percent of "air" is located in the troposphere and stratosphere. The stratopause separates the stratosphere from the next layer.

Mesosphere

The mesosphere starts just above the stratosphere and extends to 85 kilometers (53 miles) high. In this region, the temperatures again fall as low as -93 degrees Celsius as you increase in altitude. The chemicals are in an excited state, as they absorb energy from the Sun. The mesopause separates the mesophere from the thermosphere.

The regions of the stratosphere and the mesosphere, along with the stratopause and mesopause, are called the middle atmosphere by scientists. This area has been closely studied on the ATLAS Spacelab mission series.

The Ionosphere is located in the upper mesosphere and lower thermosphere. Here solar energy bombards neutral atoms causing them to lose electrons. The resulting ions (positively or negatively charged atoms). AM radio waves are reflected back to earth in this layer. Auroras also form here.

Thermosphere

The thermosphere starts just above the mesosphere and extends to 600 kilometers (372 miles) high. The temperatures go up as you increase in altitude due to the Sun's energy. Temperatures in this region can go as high as 1,727 degrees Celsius. Chemical reactions occur much faster here than on the surface of the Earth. This layer is known as the upper atmosphere.

The upper and lower layers of the thermosphere will be studied more closely during the Tethered Satellite Mission (TSS-1R).

Beyond the Atmosphere

The exosphere starts at the top to the thermosphere and continues until it merges with interplanetary gases, or space. In this region of the atmosphere, Hydrogen and Helium are the prime components and are only present at extremely low densities.

Space Ship Columbia

As the space shuttle Columbia entered the Thermosphere, high energy plasma entered the space craft. The space craft heated up because the energized gases were contained within the space craft. The gases outside the space craft move at high energies but are so sparse that they don't conduct heat.  Remember, the faster the motion of the molecules, the higher the temperature. But collisions must occur for this heat to be conducted. When the gas was contained within the spacecraft, conduction rapidly occurred.

http://www.space.com/missionlaunches/sts107_lost_030201.html

From Tarbuck and Lutgen - pg 442

Primordial Atmosphere:

Study: Hydrogen Saturated Early Earth

By Larry O'Hanlon, Discovery News

April 11, 2005 — Early Earth had a Hindenburg atmosphere: lots more hydrogen than expected, making it more likely than ever that the origins of early life were terrestrial, say experts on Earth's ancient atmosphere.

A brand new look at how quickly hydrogen escaped into space from early Earth's atmosphere puts it as a hundred times slower than long thought.

More hydrogen makes it possible to have had a much richer pre-life chemical soup spread out over a wide range of early environments. As a result, it could reverse the need for biologists to hunt for the origins of life on Earth in out-of-the-way places, or in outer space.

 

But three or four billion years ago, the sun was young and 30 percent dimmer and the Earth's atmosphere was probably more like that of Mars and Venus — rich in carbon dioxide.

Taking into account the slower hydrogen escape by Earth's two sibling planets and a cooler sun, the team's model makes it appear more likely that hydrogen escaped into space more gently and built up to about 40 percent in early Earth's atmosphere.

"This is really a fairly difficult mathematical problem," said Toon about their re-evaluation of the early atmosphere.

But the numbers they came up with show that life on Earth has a very good chance of being entirely homegrown.

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