Transcript PPT: Atmosphere and Climate

Climate and Biomes
AP Environmental Science
Mark Ewoldsen, Ph.D.
and Michael Zito
www.ai.mit.edu/people/jimmylin/pictures/2001-12-seattle.htm
Atmosphere, Climate and Biomes
• The Atmosphere
– Origin of Modern Atmosphere
– Structure
– Composition
– Energy Budget
– Climate
– Air and Ocean Circulation
– El Nino and La Nina
– Biome Distribution
Origin of Modern Atmosphere
• original atmosphere surrounded the homogenous planet
Earth and probably was composed of H and He
• second atmosphere evolved from gases from molten
Earth
– H2O, CO2, SO2, CO, S2, Cl2, N2, H2, NH3, and CH4
– allowed formation of oceans and earliest life
• modern Atmosphere
– evolved after Cyanobacteria started photosynthesizing
– oxygen produced did not reach modern levels until about 400
million years ago
www.degginger.com/digitalpage.html
Composition
•
•
•
•
Nitrogen (N2, 78%)
Oxygen (O2, 21%)
Argon (Ar, 1%)
myriad of other very
influential components are also
present which include the Water (H2O, 0 - 7%),
"greenhouse" gases or Ozone (O3, 0 - 0.01%),
Carbon Dioxide (CO2, 0.01-0.1%),
Earth’s Atmosphere
• compared to the size of
the Earth (104 km), the
atmosphere is a thin
shell (120 km).
http://www.gsfc.nasa.gov/gsfc/earth/pinatuboimages.htm
Atmosphere
Layers
•
•
•
•
•
•
Exosphere
Thermosphere
(Ionosphere)
Mesosphere
Stratosphere
Troposphere
Troposphere
• 8 to 14.5
kilometers high (5
to 9 miles)
• most dense
• the temperature
drops from about
17 to -52 degrees
Celsius
• almost all weather
is in this region
Stratosphere
• extends to 50 kilometers
(31 miles) high
• dry and less dense
• temperature in this region
increases gradually to -3
degrees Celsius, due to the
absorption of ultraviolet
radiation
• ozone layer absorbs and
scatters the solar ultraviolet
radiation
• ninety-nine percent of "air"
is located in first two
layers
• every 1000-m 11% less air
pressure
Distribution of Biomes
Radiation and The
Electromagnetic
Spectrum
10
Visible
5
0
Gamma
rays
10-14
X rays
10-12
Wavelength in meters (not to scale)
1
2
2.5
Wavelength (micrometers)
3
Low energy, long
wavelength
Nonionizing radiation
Far
Near Visible
ultraviolet ultraviolet waves
waves
waves
10-8
0.25
Infrared
Sun
High energy, short
wavelength
Ionizing radiation
Cosmic
rays
Ultraviolet
Energy emitted from sun (Kcal/cm2/min)
•
15
10-7
10-6
Near
infrared
waves
10-5
Far
infrared
waves
Microwaves
10-3
TV
waves
10-2 10-1
Radio
waves
1
Seasons on Earth
23.5º
Spring
(sun aims directly
at equator)
Solar
radiation
Summer
(northern hemisphere
tilts toward sun)
Fall
(sun aims directly at equator)
Winter
(northern
hemisphere
tilts away from
sun)
Climate
• Climate Factors:
–Air temperature
–Air pressure
–Cloud cover
–Precipitation
–Winds
Air Temperature
• Solar energy is more concentrated (J/km2)
at the equator than at the poles
• As a result, equatorial regions heat up
more than the poles.
• Warm air and water at the equator travel
poleward while cold air and water at the
poles travel equatorward in an attempt to
equalize this temperature contrast.
http://www.usatoday.com/weather/tg/wglobale/wglobale.htm
Types of Heat Transfer
Convection
Heating water in the
bottom of a pan causes
some of the water
vaporize into bubbles.
Because they are lighter
than the surrounding
water, they rise. Water
then sinks from the top to
replace the rising bubbles.
This up and down
movement (convection)
eventually heats all of the
water.
Conduction
Heat from a stove burner
causes atoms or
molecules in the pan’s
bottom to vibrate faster.
The vibrating atoms or
molecules then collide
with nearby atoms or
molecules, causing them
to vibrate faster.
Eventually, molecules or
atoms in the pan’s handles
are vibrating so fast it
becomes too hot to touch.
Radiation
As the water boils,
hear from the hot
stove burner and pan
radiate into the
surrounding air, even
though air conducts
very little heat.
Cell 3 North
Cold,
dry air
falls
•
•
•
Convection cells:
Equalizing Earth's
Energy Imbalance
Animation 1
Animation 2
Moist air rises — rain
Polar cap
Arctic tundra
Evergreen
coniferous forest
60°
Temperate deciduous
forest and grassland
Desert
30°
Cell 2 North
Cool, dry
air falls
Cell 1 North
Moist
air rises,
cools, and
releases
moisture
as rain
Tropical deciduous forest
0°
Equator
Tropical
rain forest
Tropical deciduous forest
30°
60°
Desert
Temperate deciduous
forest and grassland
Cell 1 South
Cool, dry
air falls
Cell 2 South
Polar cap
Cold,
dry air
falls
Moist air rises — rain
Cell 3 South
Air Pressure
• air pressure is caused by the weight of the air
pressing down on the Earth, the ocean and on
the air below
• the pressure depends on the amount of air above
the measuring point and falls as you go higher
• air pressure changes with weather
… and Weather
• air in a high pressure area compresses and
warms as it descends
• the warming inhibits the formation of clouds,
meaning the sky is normally sunny in highpressure areas
• haze and fog might form
• the opposite occurs in an area of low pressure
LOW
PRESSURE
HIGH
PRESSURE
Heat released
radiates to space
Cool, dry
air
Condensation
and
precipitation
Falls, is compressed, warms
Rises, expands, cools
Warm,
dry air
Hot, wet
air
Flows toward low pressure,
picks up moisture and heat
HIGH
Moist surface warmed by sun
LOW
PRESSURE
PRESSURE
Winds
• horizontal wind moves from areas of
high to low pressure
• speed is determined by differences in
pressure
• Coriolis effect causes winds to spiral
from high pressure zones and into low
pressure zones
www.iiasa.ac.at/Admin/INF/OPT/ Spring98/feature_story.htm
60ºN
Cold deserts
Westerlies
Northeast trades
Forests
30ºN
Hot deserts
Forests
Equator
Southeast trades
Hot deserts
30ºs
Westerlies
Forests
Cold deserts
60ºS
0º
The Rain Shadow Effect
Prevailing winds
pick up moisture
from an ocean.
On the windward
side of a mountain range,
air rises, cools, and
releases moisture.
On the leeward side of
the mountain range, air
descends, warms, and releases
little moisture.
Dry habitats
Moist habitats
Major Ocean Currents
Distribution of Biomes
Temperature, Precipitation and Biomes
Identify the Biome
Place
La Selva, Costa Rica
Marietta, Ohio
Pasadena California
Ferron, Utah
Tucson, Arizona
Santa Rosa, Costa Rica
Brazzaville, Congo
Lambarene, Gabon
Amauulu, Hawaii
Toolik Lake, Alaska
Beijing, China
Seoul, South Korea
Archbold Biological Station
Everglades National Park (Flamingo)
Avg Temp oC
22.1
12
18.2
8.8
21.1
26
25
25.7
20
-8.8
11.8
11.2
29.1
28.1
Annual Precipitation (cm)
403
105
51.8
20.9
21.9
165
137
195
410
18
63.5
137
131
159
Source:
http://www.marietta.edu/~biol/biomes/biome_main.htm
A Typical Climatogram
Tropical rain forest
(Manaus, Brazil)
Altitude
Mountain
Ice and snow
Tundra (herbs,
lichens,
mosses)
Coniferous
Forest
Latitude
Deciduous
Forest
Tropical
Forest
Tropical
Forest
Deciduous
Forest
Coniferous
Forest
Tundra (herbs,
lichens, mosses)
Polar ice
and snow
El Nino – Typical surface ocean circulation
El nino
conditions
• Normal
• El nino – strong
counter-current
El Nino: Normal Conditions
•
Prentice Hall Textbook animation link
El Nino: El Nino Development
•
Prentice Hall Textbook animation link
Surface winds
blow westward
EQUATOR
AUSTRALIA
Warm waters
pushed westward
SOUTH
AMERICA
Warm water
Cold water
Normal Conditions
Winds weaken,
causing updrafts
and storms
Drought in
Australia and
Southeast Asia
EQUATOR
AUSTRALIA
Warm water
flow stopped
or reversed
Warm water
SOUTH
AMERICA
Warm water deepens off
South America
Cold water
El Niño Conditions
El Nino: La Nina
•
Prentice Hall Textbook animation link
El Nino – weak Aleutian High
La Nina – strong Aleutian High
El nino - precipitation
El nino - precipitation