How is wind connected to all life on earth?

• Why is one area of the earth’s land surface a desert, and other a grassland, and another a forest?

• Why do different types of deserts, grasslands and forest exist?

Ch. 7 & 8Weather, Climate and Biomes

Key Concepts

Factors influencing weather and climate Factors influencing weather and climate

Effect of climate on distribution of biomes Effect of climate on distribution of biomes

Characteristics of major biome types Characteristics of major biome types

Saltwater and freshwater life zones Saltwater and freshwater life zones

Human impacts on biosphere Human impacts on biosphere

Weather and ClimateWeather and Climate

What is weather? What is weather?

How meteorologists predict weatherHow meteorologists predict weather

What is climate?What is climate?

temp, humidity, precipitation, sunshine, cloud cover, wind dir.

Radar, satellites, aircraft, stationary sensors, feed into computers

General pattern of atmospheric conditions over a long period

Climatograms

http://www.geocities.com/Athens/Parthenon/1020/images/des_grass.gif

Rainfall = barsTemperature = line

So all graphs have the same scale:

Rainfall (Left Y axis)3 squares = 4 cm rainfall

Temperature (R Y axis)3 squares = 8 degrees temp.

X axis Each month = 2 squares

• Interactive Climate Map

Weather– The short-term day-to-

day changes in temperature, air pressure, humidity, precipitation, sunshine, cloud cover and wind direction and speed.

– Most weather is predicted using:

weather balloons, aircraft, radar, and satellites

Weather Changes– Air Masses: large lump of air that

similar temperature and moisture level throughout.

– Air Masses that effect the US are

When air masses meet it causes changes in weather

• Cold front: when a cold air mass collides with a stationary warm air mass. The result is: thunderstorms, short bursts of heavy rain

Warm Front:

• when a warm air mass collides with a stationary cold air mass. The result is: warm steady rain

Weather is also affected by changes in atmospheric pressure

• High pressure has descending air that moves outward from the center of the high-pressure system. Descending air is warm and dry. The result is: nice dry weather

Low pressure• has ascending air that flows

towards the center of the low-pressure area. Ascending air-cools and condenses as it rises. The result is: clouds, rain

Weather Extremes– Hurricanes:

• What is it? Tropical storm with winds greater than 75 mph

• The bad: loss of life and property

• The good: flushes out coastline

Tornadoes:• Form when cold dry air collides

with warm moist air, which causes the warm air to rise quickly making a funnel cloud

Risk of Tornadoes

Highest

High

Medium

Low

Hurricane Frequency

High

Moderately high

Gulf of Alaska

Prince Williams Sound

CANADA

UNITED STATES

Grand Banks

Atlantic OceanMEXICO

Fig. 6.2, p. 122

Climate

the average weather patterns for an area overa long period of time (30 - 1,000,000 years).

is

It is determined by

Average Precipitation Average Temperatureand

which are influenced by

latitude altitude ocean currents

and affects

where people live how people livewhat they

grow and eat

Fig. 6.3, p. 123

• Interactive Climate Map

Connect these two together!

Earth: Just-right, Resilient Planet

DO NOT POST TO INTERNET Fig. 5-1, p. 92

Temperature0-100

Liquid water

Orbit-right distance

Rotation/Tilt

Size and gravity

Ozone layer-bacteria

Dry woodlands and shrublands (chaparral)

Temperate grassland

Temperate deciduous forest

Boreal forest (taiga), evergreen coniferousforest (e.g., montane coniferous forest)

Arctic tundra (polar grasslands)

Tropical savanna,thorn forest

Tropical scrub forest

Tropical deciduous forest

Tropical rain forest,tropical evergreen forest

Desert

Ice

Mountains(complex zonation)

Semidesert,arid grassland

Tropic ofCapricorn

Equator

Tropic ofCancer

Fig. 6.16, p. 131

Polar

Subpolar

Temperate

Tropical

Desert

Desert

Deciduousforest

Deciduousforest

Coniferous forestConiferous forest

ChaparralChaparral

GrasslandGrassland

SavannaSavanna

ScrublandScrublandTropical

seasonalforest

Tropicalseasonal

forest

Rain forestRain forest

TundraTundra

Fig. 6.17, p. 132

Fig. 6.6b, p. 125Initial pattern of air circulation

Deflections in the paths of air flownear the earth’s surface 

30°S

Easterlies

Westerlies

Southeasttradewinds

(Doldrums)

Northeasttradewinds

Westerlies(from the west)

Easterlies(from the east)

60°S

equator

30°N

60°N

Fig. 6-5, p. 109

Global Air CirculationAnd Biomes

Global Air currents affect regional climates

• Uneven heating of the Earth’s surface causes the equator to receive more sunlight making it hotter; the poles receive less light making them cooler. This causes: global circulation

Climate type

Cold

Cool Temperate

Warm Temperate

Tropical

(equator)

Tropical

Warm Temperate

Cool Temperate

Cold

Fig. 6.6a, p. 125

Fall(sun aims directly at equator)

Summer(northern hemisphere

tilts toward sun)

Spring(sun aims directly

at equator)

23.5 °Winter(northern hemispheretilts away from sun)

Solarradiation

Fig. 6.5, p. 124

Seasons

• Seasonal changes in temp and precipitation affect climate because the earth is tilted on its axis. It is colder in the winter and warmer in the summer because:

Coriolis Effect

• Rotation of the Earth on its axis prevents air currents from moving directly north or south causing the winds to curve in what is called:

Polar (ice)

Subarctic (snow)

Cool temperate

Warm temperate

Dry

Tropical

Highland

Major upwelling zones

Warm ocean current

Cold ocean current

River Fig. 6.4, p. 124

Ocean Currents

• Long term variations in the amount of incoming solar radiation

• Heat from the sun evaporates water and transfers energy from the ocean to the atmosphere. This creates convection cells that transport heat to different latitudes. This leads to: ocean currents and weather

Polar (ice)

Subarctic (snow)

Cool temperate

Warm temperate

Dry

Tropical

Highland

Major upwelling zones

Warm ocean current

Cold ocean current

River Fig. 6.4, p. 124

– Ocean Currents Affect climate• Differences in water temp, winds and

the rotation of the earth create currents.

• Currents redistribute heat. For example the gulf stream brings heat to Europe

Wind

Movement ofsurface water

Diving birds

Nutrients

Upwelling

Fish

Zooplankton

Phytoplankton

Fig. 6.9, p. 126

• Upwelling is created when the trade winds blow offshore pushing surface water away from land. The outgoing surface water is replaced by nutrient bottom water. Upwelling support:

The El Nino Southern Oscillation occurs every few years in the Pacific Ocean

– In an ENSO, prevailing westerly winds weaken or stop

– Surface waters along the coast of North America and South America (west) become warmer

– Normal upwelling stops– This reduces the population of some fish

species– Also causes severe weather, storms in

the US especially CA, and drought in southeast Asia

http://stateimpact.npr.org/texas/2012/08/16/drought-update-no-improvement-here-but-el-nino-is-coming/

• El Nino Video Clip - Bing Videos

El Niño-Southern Oscillation: ENSO

Fig. 6-7, p. 110Fig. 6-7, p. 110

La Nina

• La Ninas follow an El Nino and are characterized by cooling trends. La Nina brings more Atlantic hurricanes, colder winters in the north and warmer winters in the south, and an increase in tornadoes.

Greenhouse Effect

Fig. 6-9, p. 111Fig. 6-9, p. 111

Rays of sunlight penetrate the lower atmosphere and warm the earth's surface.

The earth's surface absorbs much of the incoming solar radiation and degrades it to longer-wavelength infrared radiation (heat), which rises into the lower atmosphere. Some of this heat escapes into space and some is absorbed by molecules of greenhouse gases and emitted as infrared radiation, which warms the lower atmosphere.

As concentrations of greenhouse gases rise, their molecules absorb and emit more infrared radiation, which adds more heat to the lower atmosphere.

(a) (b) (c)

Fig. 6.13, p. 128

Ozone Layer• The ozone layer is located in the

stratosphere. It is created when ultraviolet light turns oxygen into ozone. The chemical reactions is:– Ozone blocks all short wavelength UV-C radiation,

50% of the UV-B radiation and almost no long wavelength UV-A radiation.

– Ozone also forms a thermal cap which: traps heat

MicroclimatesMicroclimates

Fig. 6-10, p. 112Fig. 6-10, p. 112Fig. 6-10, p. 112Fig. 6-10, p. 112

Rain shadow effectRain shadow effectRain shadow effectRain shadow effect

aa Winds carry Winds carrymoisture inlandmoisture inland

from Pacific Oceanfrom Pacific Ocean

bb Clouds, rain on Clouds, rain onwindward side ofwindward side ofmountain rangemountain range

cc Rain shadow on Rain shadow onleeward side ofleeward side ofmountain rangemountain range

Moist habitatsMoist habitats

Dry habitatsDry habitats

CitiesCitiesCitiesCitiesLand-ocean interactionsLand-ocean interactionsLand-ocean interactionsLand-ocean interactions

Topography of the earth also creates microclimates

A microclimate is small area that has a different climate than the general climate of an area.– Vegetation in an area influences climate:

forests stay warmer in the winter and cooler in the summer because of the trees

– Cities create heat islands that trap heat and decrease wind

speeds

Cool airdescends

Land warmer thansea; breeze flowsonshore

Warm air ascends

Fig. 6.15a, p. 130

Water also changes climate by causing land breezes and sea breezes

Warm air ascends Land cooler than

sea; breeze flowsoffshore

Cool airdescends

Fig. 6.15b, p. 130

Dry woodlands and shrublands (chaparral)

Temperate grassland

Temperate deciduous forest

Boreal forest (taiga), evergreen coniferousforest (e.g., montane coniferous forest)

Arctic tundra (polar grasslands)

Tropical savanna,thorn forest

Tropical scrub forest

Tropical deciduous forest

Tropical rain forest,tropical evergreen forest

Desert

Ice

Mountains(complex zonation)

Semidesert,arid grassland

Tropic ofCapricorn

Equator

Tropic ofCancer

Fig. 6.16, p. 131

AlpineTundra

MontaneConiferous

Forest

DeciduousForest

TropicalForest

Tropical Forest Temperate Deciduous Forest

Northern Coniferous Forest

Arctic Tundra

LowHigh Moisture Availability

High

LowE

levation

Fig. 6.18, p. 133

Plant and animal adaptations to climate

– For plants precipitation is generally the limiting factor in determining whether a climate is a desert, forest or grassland, but biomes are not uniform. They have the same general characteristics but there are microclimates that determine the actual plants you will find in any given area.

Plants exposed to cold year around or in the winter have:

• Traits that keep them from losing too much heat or water

• They stay small

Desert plants must be able to lose heat and conserve water. They do this by:

• Lose heat and store water

• Fleshy tissue, vertical, no leaves, store water

In wet tropical climates the plants have

• Broadleaf evergreen, maximize sunlight

In climates that are hot in summer and cold in winter, plants have:• Deciduous leaves that fall off in

winter

In areas with cool short summers, the trees have:

• Coniferous evergreen

• Needle shaped leaves