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

• Exosphere • Thermosphere• (Ionosphere)• Mesosphere• Stratosphere • Troposphere

AtmosphereLayers

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

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

Major Ocean Currents

Distribution of Biomes

Temperature, Precipitation and Biomes

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

Tropical rain forest

(Manaus, Brazil)

A Typical Climatogram

MountainIce and snow

Altitude

Tundra (herbs,lichens, mosses)

ConiferousForest

Tropical Forest

DeciduousForest

Tropical Forest

DeciduousForest

ConiferousForest

Tundra (herbs,lichens, mosses)

Polar iceand snow

Latitude

El Nino – Typical surface ocean circulation

El nino conditions

• Normal

• El nino – strong counter-current

• Prentice Hall Textbook animation link

El Nino: Normal Conditions

• Prentice Hall Textbook animation link

El Nino: El Nino Development

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

• Prentice Hall Textbook animation link

El Nino: La Nina

El Nino – weak Aleutian High

La Nina – strong Aleutian High

El nino - precipitation

El nino - precipitation