Transcript Environmental Science - Manistique Area Schools

Environmental
Science
Chapter 7
Notes #1
Atmosphere
• Thin Layer of gases that surrounds the Earth
• Extends from the surface to 100’s of km’s
above
• “Air”
– Composition
• 78% Nitrogen
• 21% Oxygen
• 1% = water vapor, argon, carbon dioxide, neon,
helium, and others
– 2 most important
• Oxygen for respiration
• Carbon Dioxide for photosynthesis
Atmosphere
• Living organisms appeared about 4
billion years ago
– Changed out the atmosphere
• Depleted the oxygen
– Plant evolved to photosynthesize
– Allowed for increased oxygen in the
atmosphere
• Photosynthesis and Respiration
keep oxygen and carbon dioxide
constant
Atmosphere
• Our atmosphere has 5 layers
– The layers get less dense the
further you move out from
Earth’s surface
• 1. Troposphere
–
–
–
–
Nearest to Earth’s Surface
Extends out to 10 km (6 mi)
Where most weather occurs
Contains 90% of the
atmosphere’s gases
Atmosphere
2. Stratosphere
1. 10 km to 50 km (about 30 mi)
2. Less dense than troposphere
3. Contains the ozone layer
1. Protects us from UV rays
4. Wind blows – not as much
turbulence as in troposphere
3. Mesosphere
1. 50 km to 80 km (about 50 mi)
2. Less dense than the
troposphere and the
stratosphere
Atmosphere
4. Thermosphere
1. 80 km to 500 km (310 mi)
2. Less dense than all three of the
above
5. Exosphere
1. Beyond the thermosphere
2. Gases become thinner and
thinner
3. It eventually just merges with
outer space
Climate
• Weather
– What is happening in the atmosphere
at a particular place at a particular
time
• Climate
– Average weather in an area over a
long period of time
Temp and precip.
– Aspects of climate
Generally
determines what
• Temperature
type of organisms
• Humidity
are able to live in
• Wind
a particular region
• Precipitation
What Determines Climate?
1. Latitude
1. Distance from the equator
2. Measured in degrees N or S
3. Solar energy received depends on latitude
2. Air Circulation
1.
2.
3.
4.
Cold air sinks and warms as it does so
Warm are rises and cools as it does so
Warm air holds more water than cold air
As warm air rises it causes wind (mvmt of
air)
5. End result – areas of heavy precipitation,
dry areas, etc.
What Determines Climate?
3. Ocean Currents
1. Currents redistribute large masses of hot
and cold water
2. Mvmt cause by winds and rotation of the
Earth
3. Oceans make climates more moderate
(warm winters and cool summers)
4. Local Geography
1. Height above sea level affects temp
2. Mountains influence the distribution of
precipitation
Seasonal Change in Climate
• Result in Earth’s orbit around the
sun
• In the Northern Hemisphere the
Earth tilts so that we get more direct
sunlight in the summer than in the
winter
• We are closest to the sun in the
winter!
• Equator gets direct sunlight year
around – so its always warm
(tropics)
Seasonal Change in Climate