Send the link below via email or IMCopy
Present to your audienceStart remote presentation
- Invited audience members will follow you as you navigate and present
- People invited to a presentation do not need a Prezi account
- This link expires 10 minutes after you close the presentation
- A maximum of 30 users can follow your presentation
- Learn more about this feature in our knowledge base article
Transcript of Atmosphere
The ionosphere is very thin, but it is where aurora take place, and is also responsible for absorbing the most energetic photons from the Sun, and for reflecting radio waves, thereby making long-distance radio communication possible.
When you see the top of a thunderstorm flatten out into an anvil cloud, like in the illustration above, it is usually because the updrafts in the storm are "bumping up against" the bottom of the stratosphere
The warming of the atmosphere by its absorbing and emitting infrared radiation while allowing shortwave radiation to pass through.
Atmospheric Greenhouse Effect
Nitrogen - 78%
Composition of Atmosphere
c) the electrically charged ionosphere
Atmospheric Mixture & Charge
Atmospheric pressure decreases rapidly with height. Climbing to an altitude of only 5.5 km where the pressure is 500 mb, would put you above one-half of the atmosphere’s molecules.
Vertical Pressure Profile
AM radio waves are long enough to interfere with ions in the sun-charged D layer (Ionosphere) but at night the D layer (ionosphere) is weak and the AM signal propagates further, requiring stations to use less power.
Figure 1.9 (Ionosphere Radio Prop)
Radio Wave Propagation
Air Density is
The number of air
Molecules in a given
Gravity pulls gases toward earth's surface, and the whole column of gases weighs 14.7 psi at sea level, a pressure of 1013.25 mb or 29.92 in.Hg.
The amount of force exerted Over an area of surface is called
Pressure & Density
Human and natural activities displace tiny soil, salt, and ash particles as suspended aerosols,
as well as sulfur and nitrogen oxides, and hydrocarbons as pollutants.
Aerosols & Pollutants
Nitrogen and oxygen concentrations experience little change, but carbon dioxide, methane, nitrous oxides, and chlorofluorocarbons are greenhouse gases experiencing discernable increases in concentration. CO2 has risen more than 18% since 1958. Fossil fuels are the biggest problem!
Variable & Increasing Gases
Ozone – is the primary ingredient of smog!
Ground based smog, which is visible, contains reactants of nitrogen and ozone.
99% of atmospheric gases, including water vapor, extend only 30 kilometer (km) above earth's surface.
Most of our weather, however, occurs within the first 10 to 15 km.
Nearly 150 million kilometers separate the sun and earth, yet solar radiation drives earth's weather.
Solar Energy as Radiation
“Hot layer” – oxygen molecules absorb energy from solar Rays warming the air. Very few atoms and molecules in this Region.
Middle atmosphere – Air thin, pressure low,
Need oxygen to live in this region. Air quite Cold -90°C (-130°F) near the top of mesosphere
Temperature inversion in stratosphere
Ozone plays a major part in heating the air
At this altitude
Tropopause separates Troposphere from
Stratosphere. Generally higher in summer
Lower in winter.
Troposphere – Temp decrease w/ height
Most of our weather occurs in this layer
Varies in height around the globe, but
Averages about 11 km in height.
Nitrogen, oxygen, argon, water vapor, carbon dioxide, and most other gases are invisible.
Clouds are not gas, but condensed vapor in the form of liquid droplets.
8 layers are defined by constant trends in average air temperature (which changes with pressure and radiation), where the outer exosphere is not shown.
Oxygen - 21%
Water Vapor – 0 to 4%
Carbon Dioxide - .037%
Other gases make up the rest
The gases mainly responsible for the earth’s atmospheric greenhouse effect are water vapor and carbon dioxide.
The troposphere is the lowest major atmospheric layer, and is located from the Earth's surface up to the bottom of the stratosphere.
It has decreasing temperature with height (at an average rate of 3.5° F per thousand feet (6.5 ° C per kilometer);
The stratosphere has either constant or slowly increasing temperature with height.
It is where all of Earth's weather occurs.
The boundary that divides the troposphere from the stratosphere is called the "tropopause", located at an altitude of around 5 miles in the winter, to around 8 miles high in the summer, and as high as 11 or 12 miles in the deep tropics.
The Stratosphere and Ozone Layer
The Mesosphere and Ionosphere
Above the troposphere is the stratosphere, where air flow is mostly horizontal.
The thin ozone layer in the upper stratosphere has a high concentration of ozone, a particularly reactive form of oxygen.
This layer is primarily responsible for absorbing the ultraviolet radiation from the Sun.
The formation of this layer is a delicate matter, since only when oxygen is produced in the atmosphere can an ozone layer form and prevent an intense flux of ultraviolet radiation from reaching the surface, where it is quite hazardous to the evolution of life.
There is considerable recent concern that man-made fluorocarbon compounds may be depleting the ozone layer, with dire future consequences for life on the Earth.
Above the stratosphere is the mesosphere and above that is the ionosphere (or thermosphere), where many atoms are ionized (have gained or lost electrons so they have a net electrical charge).
Additional layers include:
a) the homosphere with 78% nitrogen and 21% oxygen
b) the poorly mixed heterosphere