Climate and Biomes
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Climate and BiomesClimate and Biomes
AP Environmental ScienceAP Environmental Science
Mark Ewoldsen, Ph.D.Mark Ewoldsen, Ph.D.and Michael Zitoand Michael Zito
www.ai.mit.edu/people/jimmylin/pictures/2001-12-seattle.htm
Atmosphere, Climate and Biomes• The AtmosphereThe Atmosphere
– Origin of Modern AtmosphereOrigin of Modern Atmosphere– StructureStructure– CompositionComposition– Energy BudgetEnergy Budget– ClimateClimate– Air and Ocean CirculationAir and Ocean Circulation– El Nino and La NinaEl Nino and La Nina– Biome DistributionBiome 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%),
• compared to the size of the Earth (104 km), the atmosphere is a thin shell (120 km).
Earth’s Atmosphere
http://www.gsfc.nasa.gov/gsfc/earth/pinatuboimages.htm
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
SunHigh energy, short
wavelengthLow energy, long
wavelengthIonizing radiation Nonionizing radiation
Cosmicrays
Gammarays
X rays Farultraviolet
waves
Nearultraviolet
waves
Visiblewaves
Nearinfraredwaves
Farinfraredwaves
Microwaves TVwaves
Radiowaves
Wavelength in meters (not to scale)
10-14 10-12 10-8 10-7 10-6 10-5 10-3 10-2 10-1 1
En
ergy em
itted
from
sun
(K
cal/cm
2/m
in)
0
5
10
15
0.25 1 2 2.5 3Wavelength (micrometers)
Visible
InfraredU
ltravio
le
t
• Radiation and The Electromagnetic Spectrum
Fall(sun aims directly at equator)
Summer(northern hemisphere
tilts toward sun)
Spring(sun aims directly
at equator)
23.5º
Winter(northern
hemispheretilts away from
sun)
Solarradiation
Seasons on Earth
ClimateClimate
• Climate Factors:Climate Factors:–Air temperature Air temperature –Air pressure Air pressure –Cloud cover Cloud cover –Precipitation Precipitation –Winds Winds
Air Temperature
• Solar energy is more concentrated (J/km2) Solar energy is more concentrated (J/km2) at the equator than at the polesat the equator than at the poles
• As a result, equatorial regions heat up As a result, equatorial regions heat up more than the poles. more than the poles.
• Warm air and water at the equator travel Warm air and water at the equator travel poleward while cold air and water at the poleward while cold air and water at the poles travel equatorward in an attempt to poles travel equatorward in an attempt to equalize this temperature contrast. equalize this temperature contrast.
• It is the atmosphere's continual struggle for It is the atmosphere's continual struggle for temperature balance that brings us our temperature balance that brings us our changing weather. changing weather.
http://www.usatoday.com/weather/tg/wglobale/wglobale.htm
Types of Heat Transfer
Convection Conduction Radiation
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.
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.
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 South
Cold,dry air falls
Moist air rises — rain
Cell 2 South
Cool, dryair falls
Cell 1 South
Moistair rises,cools, andreleasesmoistureas rain
Cell 1 North
Cool, dryair falls
Cell 2 North
Moist air rises — rain
Cell 3 NorthCold,dry airfalls
Polar cap
Arctic tundra
60°
30°
0°
30°
60°
Polar cap
Evergreenconiferous forest
Temperate deciduousforest and grassland
Desert
Tropical deciduous forest
EquatorTropical rain forest
Tropical deciduous forest
DesertTemperate deciduousforest and grassland
• Convection cells: Equalizing Earth's Energy Imbalance
• Animation 1
• Animation 2
Air Pressure
• air pressure is caused by the weight of the air air pressure is caused by the weight of the air pressing down on the Earth, the ocean and on pressing down on the Earth, the ocean and on the air belowthe air below
• the pressure depends on the amount of air above the pressure depends on the amount of air above the measuring point and falls as you go higher the measuring point and falls as you go higher
• air pressure changes with weatherair pressure changes with weather
… … and Weatherand Weather
• air in a high pressure area compresses and air in a high pressure area compresses and warms as it descendswarms as it descends
• the warming inhibits the formation of clouds, the warming inhibits the formation of clouds, meaning the sky is normally sunny in high-meaning the sky is normally sunny in high-pressure areaspressure areas
• haze and fog might formhaze and fog might form
• the opposite occurs in an area of low pressurethe opposite occurs in an area of low pressure
Moist surface warmed by sun
Flows toward low pressure,picks up moisture and heat
Warm,dry air
Hot, wetair
Falls, is compressed, warms Rises, expands, cools
Heat releasedradiates to space
LOWPRESSURE
HIGHPRESSURE
Cool, dryair
Condensationand
precipitation
HIGHPRESSURE
HIGHPRESSURE
LOWPRESSURE
LOWPRESSURE
Winds
• horizontal wind moves from areas of horizontal wind moves from areas of high to low pressure high to low pressure
• speed is determined by differences in speed is determined by differences in pressurepressure
• Coriolis effectCoriolis effect causes winds to spiral causes winds to spiral from high pressure zones and into low from high pressure zones and into low pressure zonespressure zoneswww.iiasa.ac.at/Admin/INF/OPT/ Spring98/feature_story.htm
60ºN
30ºN
0º
30ºs
60ºS
Cold deserts
Westerlies Forests
Hot desertsNortheast trades
Forests
Equator
Hot deserts
Forests
Southeast trades
Westerlies
Cold deserts
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.
Moist habitats
Dry habitats
The Rain Shadow EffectThe Rain Shadow Effect
Identify the BiomePlaceLa Selva, Costa RicaMarietta, OhioPasadena CaliforniaFerron, UtahTucson, ArizonaSanta Rosa, Costa RicaBrazzaville, CongoLambarene, GabonAmauulu, HawaiiToolik Lake, AlaskaBeijing, ChinaSeoul, South KoreaArchbold Biological StationEverglades National Park (Flamingo)
Avg Temp oC22.112
18.28.8
21.12625
25.720
-8.811.811.229.128.1
Annual Precipitation (cm)40310551.820.921.916513719541018
63.5137131159
Source: http://www.marietta.edu/~biol/biomes/biome_main.htm
MountainIce and snow
Altitude
Tundra (herbs,lichens, mosses)
ConiferousForest
Tropical Forest
DeciduousForest
Tropical Forest
DeciduousForest
ConiferousForest
Tundra (herbs,lichens, mosses)
Polar iceand snow
Latitude
Normal Conditions
Cold water
Warm water
Thermocline
SOUTHAMERICA
Warm waterspushed westward
AUSTRALIA
EQUATOR
Surface windsblow westward
El Niño Conditions
Cold water
Thermocline
Warm waterWarm water deepens offSouth America
SOUTHAMERICA
Warm waterflow stoppedor reversed
AUSTRALIA
EQUATOR
Drought inAustralia andSoutheast Asia
Winds weaken,causing updraftsand storms
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