Chapter 16: The Atmosphere: Composition, Structure, & Temperate Flashcards
Weather, what is it?
- Occurs over a short period of time
- Constantly changing
- Refers to state of atmosphere
Climate, what is it?
- Occurs over a long period of time
* Composite of weather conditions over many years
Regularly measured properties of weather and climate?
- temp
- humidity
- cloudiness
- precipitation
- air pressure
- wind speed and direction
The atmosphere is made up of what components?
- Nitrogen -78%
- Oxygen -21%
- Argon and other gases- .93%
- Carbon Dioxide -.036%
Three components is the air
1) Water vapor
2) Aerosols
3) Ozone
What is water vapor?
- Varies considerably
- 4% of air’s volume
- Forms cloud and precipitation
- Absorbs heat energy from Earth
What is aerosols?
- Tiny sold and liquid particles (dust, pollen, ect)
- Particles reflect sunlight
- Helps to color sunrises and sunsets
What is an ozone?
- Form of oxygen that combines 3 oxygen atoms into each molecule
- Absorbs harmful ultraviolet radiation from sun
Explain Pressure Changes
- Pressure is the weight of the air
- Average sea level pressure about 14.7 pounds per square inch
- Pressure decreases with altitude (90% found within 10 miles of Earth’s surface)
What is a Radiosonde?
an instrument carried aloft, by a weather balloon to gather and transmit meteorological data
*balloon expands as it rises/ pressure decreases / when popped sends parachute down and then it is tracked on a GPS
The layers of the atmosphere is based on what?
temperature
What is the Troposphere?
- The bottom layer of the atmosphere
- Temp decrease w/ altitude called environmental lapse rate
- The outer boundary is called the “tropopause”
What is the Stratosphere?
- Between 12 km to 50 km above earth. aka below middle
- Temp increases here where the ozone layer is concentrated
- Outer boundary is called the stratopause
What is the Mesosphere?
- Between 50 km to 80 km above earth. aka middle
- Temp decreases steadily; coldest temps occur here
- Outer boundary called mesopause
What is the Thermosphere?
- does not have well-defined upper limit.
- gases are moving at high speeds
- temp starts to increase dot to high energy solar radiation. aka highest part
Two motions of the Earth
1) Rotation-
Earth fully rotates on axis every 24hrs
Produces daily cycle of day & night
2) Revolution-
Movement of earth on orbit around the sun.
1 revolution/ year
Why do we experience seasons on earth?
Because of the tilt of the Earth axis!
Happens when the sun hits the earth
A result of Earth’s changing orientation to the Sun is what?
Seasons!
The Earth’s axis is at
23.5 degrees
When does the Summer Solstice happen for us?
- June 21, most hours of daylight
- **Earth is tilted on angle towards the sun
- Suns vertical rays are located at the Tropic of Cancer
When does the Winter Solstice happen for us?
- December 21, fewest hours of daylight
- Earth is tilted away from the sun
- Suns vertical rays are located at the Tropic of Capricorn
When does the Fall (Autumnal) equinox and Spring (Vernal) equinox happen for us?
FALL September 21
SPRING March 21
- Days and nights are equal
- Suns vertical rays are located at the equator
Three mechanisms of heat transfer
1) Conduction: transfer of heat through molecular activity
2) Convection: transfer of heat through mass movement
3) Radiation: doesn’t need a medium to travel. This is how heat from the Sun reaches our planet.
Possible effects when radiation strikes and object
1) Reflection (% of radiation reflected)
2) Scattering
3) Absorption
What is reflection?
the process of when light bounces back from an object at the same angle and intensity, which it hit the surface
What is scattering?
produces a larger number of weaker rays that travel in different directions
Atmospheric Heating
1) Short-wave solar radiation pass through the atmosphere & partially absorbed
2) Radiation from Earth’s surface:
A. Earth re-radiates radiation
B. Longer wavelength terrestrial radiation is absorbed by carbon dioxide& water vapor
C. Greenhouse gases re-radiate some energy back toward earth, trapping heat in lower atmosphere
What is the most important control of temperature?
solar radiation
Variations in temperatures are greatest when?
They are greatest when over land
