Transcript Climates of the Earth

Mr. Marston
Geography 9th grade
DCHS
Marietta, GA
CLIMATES OF THE EARTH
WEATHER
Condition in the atmosphere
in one place during a limited
period of time. It’s the day to
day temperature and
precipitation.
Common types of weather are
wind, clouds, rain, snow, fog,
and dust storms.
Less Common events are
tornadoes, hurricanes, and
ice storms.
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CLIMATE:
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WEATHER VS. CLIMATE
Term for the weather
patterns that an area
typically experiences over a
period of time. The standard
averaging period is 30 years.
(Temperatures, humidity,
atmospheric pressure,
winds, and rainfall)
EARTH’S TILT AND ROTATION
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Earth is closest to the sun in
January (91,405,000) miles and
farthest from the sun in July (94,
511,000) miles.
Seasons are determined by the
tilt of the earth and not the
Earth’s proximity to the sun.
Earth’s axis is tilted at 23.5
degrees, which affects
temperature.
One complete rotation every 24
hours, from west to east, about
1,000 miles per hour. Rotation
gives us night and day.
Revolution: one trip around the
sun takes 365 days plus a few
hours.
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The shape of Earth’s orbit
becomes more or less oval
(eccentricity)
Earth wobbles as it spins
(precession)
Earth's axis changes too
(tilt).
All these changes, over
thousands of years, causes
Earth's climate to change.
CHANGES IN EARTH’S ORBIT CAUSES CLIMATE
TO CHANGE
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Changing intensity and changing amount of
sunlight to the different hemispheres gives rise to
the seasons of summer, fall, winter, and spring.
Summer solstice: In the northern hemisphere,
around June 21. Marks the point at which the
north pole of the earth is tilted at its maximum
towards the sun. Longest day of the year in the
northern hemisphere. Marks the beginning of
the winter for the southern hemisphere.
Winter Solstice: first day of winter for the northern
hemisphere, around December 21st. The day the
north pole of the earth is tilted at its maximum
away from the Sun. Shortest day of the year in the
northern hemisphere.
Autumnal Equinox: Beginning of fall in the
northern hemisphere, around September 23rd.
Vernal Equinox: Beginning of spring in the
northern hemisphere, around March 21st.
Equinox: “Equal night.” Neither the north pole nor
the south pole is inclined towards the sun. On the
vernal and autumnal equinoxes, day and night are
about the same length all over the world.
SEASONS
HTTP://WWW.WINDOWS.UCAR.EDU/TOUR/LI
NK=/THE_UNIVERSE/UTS/IMAGES/SEASONS
_BIG_GIF_IMAGE.HTML CLIMATIC CHANGE
EQUINOX
LAND OF THE
MIDNIGHT SUN
“Yesterday, I played golf at
11:30p.m, and the day before I
went for a long walk at 2am. It
doesn’t matter what time it is,
and I need less sleep.”
Visitor to Norway
North Pole: sun doesn’t set from
March 20 to Sept. 23rd.
South Pole: Sept. 23 to March 20.
One pole is tilted towards the sun
and receives continuous sunlight
while the other pole is tilted away.
Arctic Cathedral in Norway
Midnight sun at Nordkapp, Norway
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NORDKAPP, NORWAY
GREENHOUSE EFFECT
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Atmosphere traps sun
to warm the planet
If too much heat
escapes, plants will
freeze. If too hot, the
plants will die.
Conditions in the
atmosphere must be
regulated.
THE GREENHOUSE EFFECT
USEFUL WEBSITES ON GLOBAL WARMING
http://www.knowledge.firemansfund.com/pdf/
graphics/what_is_global_warming.pdf
 http://hyperphysics.phyastr.gsu.edu/hbase/thermo/grnhse.html#c4
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SKEPTICAL VIEWS OF GLOBAL WARMING
The view of most climate scientists is that rising CO2 in the atmosphere, primarily from human
activity, is driving the current increase in global temperature.
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Climate modeling is very complex, the stakes are very high, and there are numerous special
interests.
Skeptical views on CO2 global warming
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The CO2 is not sufficient to drive the currently observed warming.
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The atmospheric CO2 level has been up to 10 times higher in the past. Why weren't there
catastrophic consequences then?
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Much of this century’s temperature rise was in early years when industrial emissions were
small, and there was a temperature decrease during the postwar economic boom.
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Ice core records show CO2 rises lagging temperature rises rather than driving them.
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Surface warming is more than atmospheric warming, in contrast to CO2-driven models.
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The global temperature of the past century correlates more strongly with solar activity than with
CO2.
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The sunspot activity of our Sun and the associated magnetic fields divert some of the cosmic
rays that nucleate clouds on the Earth.
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FACTORS AFFECTING CLIMATE: LATITUDES
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Low Latitudes: between the Tropics,
which includes the Equator
Receives direct sun year round
Warm to hot climates
Mid Latitudes: area north of the
Tropic of Cancer to the Arctic Circle
and area south of the Tropic of
Capricorn to the Antarctic Circle.
Temperate climate
Ranges from fairly hot to fairly cold
Experiences seasonal weather
changes
High Latitudes: area near the north
and south poles. One pole receives
continuous sunlight depending on
season.
FACTORS AFFECTING CLIMATE: ELEVATION
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Relationship between elevation
and temperature
An elevation increases,
temperatures decreased by about
3.5 degrees per 1,000 feet
Sunlight is brighter in higher
elevations because the thinner
atmosphere filters fewer rays of
the sun.
Picture of Quito, Ecuador
OCEAN CURRENTS
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Warm ocean currents
are corridors of warm
water moving from the
tropics to the poles
where they release
energy to the air.
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Cold ocean currents are
corridors of cold water
moving from higher
latitudes toward the
equator. They absorb
energy received in the
tropics thus cooling the
air above.
WIND ZONES
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The wind zones are created by the heating (and rising)
and cooling (and sinking) of air masses at the equator
and the poles.
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Pressure systems produced by the rising and sinking of
air masses lead to wind zones. The circulation of our
atmosphere is complicated by the Earth's rotation and
tilt. The Earth's axis is tilted 23.5° from being
perpendicular to the elliptical plane, the plane of its orbit
around the sun. The tilt of the axis allows unequal
heating of the Earth's surface, causing wind.
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Air warmed by the Sun rises at the Equator, cools as it
moves toward the poles, descends as cold air over the
poles, and warms again as it moves over the surface of
the Earth toward the Equator. This simple pattern of
atmospheric convection is complicated by the rotation of
the Earth, which introduces the Coriolis Effect. Thus, a
wind traveling north from the equator will maintain the
sideways velocity acquired at the equator while the Earth
under it is moving sideways slower. This effect accounts
for the winds turning toward the right as it moves
northward across the Earth's surface.
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Winds blow between areas of different atmospheric
pressures, from high pressure areas to low pressure
areas. The Coriolis Effect also causes these winds to
turn right in the Northern Hemisphere, and left in the
Southern hemisphere. In the zone between about 30°
N. and 30° S., the surface air flows toward the Equator,
WIND ZONES II
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A low-pressure nearly windless zone at the Equator is known as the doldrums. Around 30° N.
and S., the air flowing towards the poles in the upper atmosphere begins to descend toward the
surface in high-pressure nearly windless belts. The sinking air is relatively dry because its
moisture has already been released as it rose, cooled, and condensed above the Equator,
creating the tropical rain forests. This high-pressure nearly windless zone of descending air is
called the Horse Latitudes. The name for this area is believed to have been given by sailors,
whose ships stalled at these latitudes while crossing the oceans (with horses as cargo), and
were forced to throw a few horses overboard to conserve water.
The surface air that flows from these subtropical high–pressure belts toward the Equator is
deflected toward the west by the Coriolis Effect. Because winds are named for the direction
from which the wind is blowing, the trade winds are called easterlies. The trade winds meet at
the doldrums. Surface winds known as prevailing westerlies flow from the Horse Latitudes
toward the poles. This is our wind zone, so most of our weather comes from the west,
specifically from the southwest to the northeast. The "westerlies" meet "easterlies" from the
polar regions at about 50–60° N. and S, causing a windless zone called the subpolar lows.
Since surface winds “drive” the ocean currents, both air and water circulation are controlled by
all these factors.
WIND ZONES III
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Low Pressure: created
when warm air from the
equator heats and rises
and becomes lighter
than the surrounding
air.
High Pressure: created
in cooler areas when air
sinks because it is
heavier.
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Winds will blow as air is
squashed out by the
sinking cold air and
drawn in under the rising
warm air.
Any difference in
temperature will create a
difference in air pressure
resulting in winds that
will blow.
Winds blow from high
pressure to low pressure.
WIND ZONES IV VOCABULARY RECAP
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Doldrums: Windless zone at the equator
caused by warm rising air.
Horse Latitudes: Subtropical high,
windless zones caused by sinking air at 30
degrees north and south of the equator.
Subpolar low: windless zones produced
when the winds of the polar easterlies and
prevailing westerlies meet, leading to an
upward motion of the air at approximately
60 degrees north and south of the
equator.
Polar Highs: windless zone produced by
sinking air above both poles.
Trade Winds: easterly horizontal surface
winds that move between the horse
latitudes and the subpolar lows.
Prevailing westerlies: westerly horizontal
surface winds that move between the
subpolar lows and the poles.
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Polar easterlies: easterly horizontal surface
winds that move between the subpolar lows
and the poles.
Jet Stream: area of swiftly flowing upper libel
winds located at the convergence of the
main wind belts. Flows in a west to east
direction at speeds exceeding 200 mph and
heights of 5-7 miles.
Coriolis Effect: turning of moving bodies due
to the rotation of the earth on its axis. Turns
to the right in the northern hemisphere and
to the left in the southern hemisphere.
FACTORS AFFECTING CLIMATE: OCEAN
CURRENTS
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http://www.atmo.arizon
a.edu/products/wximag
ery/globalir.html
EL NINO
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El Nino is a temporary change in the climate of the
Pacific ocean, in the region around the equator
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Causes: Winds that push water from east to west
along the equator in the Pacific have weakened. In
normal weather patterns, strong winds blow from
east to west that piles up water in the western
Pacific, which allows deeper cold water in the east
to replace the warmer water that had been pulled
to the west. Normal situation is warm water in the
west and cold water in the east. However, El Nino
doesn’t allow this temperature difference to occur
so warm water in the west falls back to the east
and not enough cold water gets pulled up.
Result: warmer ocean affects the winds and
makes them weaker, then the winds get weaker
and the ocean gets warmer, and so on.
Effect: wet winters in SE US. Wet weather along the
coasts of North and South America, Drought in
Indonesia and Australia.
Duration: one year or more.
Often: about one every three to seven years.
EL NINO EFFECTS
LA NINA: OPPOSITE OF EL NINO
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Cold temperatures in
the Pacific.
Cold water and strong
winds push more water
than normal to the
western Pacific.
Result: Very wet in Se
Asia and Australia, mild
winter in SE US and
cooler in NW US.
LA NINA EFFECTS
RAIN SHADOW
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Area of dry land that lies on the leeward (downside) of a
mountain.
Winds carry air masses up and over the mountain range
and as the air is driven upward over the mountain, falling
temperatures cause the air to lose much of its moisture
as precipitation.
Upon reaching the leeward side of the mountain, the dry
air descends and picks up any available moisture from
the landscape below.
Result: Rainfall and moist air prevails on the windward
side of a mountain range while arid, moisture-poor air
prevails on the leeward side of the mountain range.
Examples of dry, rain shadow regions and the mountain
ranges that shield them:
The Gobi Desert lies in the rain shadow of the
Himalayas.
The Atacama Desert lies in the rain shadow of the Andes
The Patagonia region lies in the rain shadow of the
Andes.
Death Valley lies in the rain shadow of the Pacific Coast
Ranges of California and the Sierra Nevada Mountains
Spokane, Washington lies in the rain shadow of the
Cascade Mountain Range while Seattle, Washington lies
on the windward side of the Cascades.
RAIN SHADOW ON MOLOKAI, HAWAII
TYPES OF CLOUDS
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Clouds are visible accumulations of water droplets
or solid ice crystals that float in the Earth's
troposphere.
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How Clouds Form: Clouds form when water vapor
(water that has evaporated from the surface of the
Earth) condenses (turns into liquid water or solid
ice) onto microscopic dust particles (or other tiny
particles) floating in the air. This condensation
(cloud formation) happens when warm and cold air
meet, when warm air rises up the side of a
mountain and cools as it rises, and when warm air
flows over a colder area, like a cool body of water.
This occurs because cool air can hold less water
vapor than warm air, and excess water condenses
into either liquid or ice.
CLOUD TYPES
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Prefixes and Suffixes Used to Describe Clouds:
Clouds are defined by both the way they look and how
high they are in the atmosphere. For example, cirro
(meaning "wisp of hair") is a prefix given to high-altitude
clouds (above 20,000 feet). Alto (meaning "high") is a
prefix given to mid-altitude clouds (between 6,000 and
20,000 feet). There is no prefix for low-altitude clouds.
When clouds are by the ground we call them fog. Nimbo
(meaning "rain") as a prefix, or nimbus added as a suffix,
in a cloud name indicates that the cloud can produce
precipitation (rain, snow, or other forms of falling water).
Cumulo (meaning "heap") refers to piled-up clouds.
Strato (meaning "layer") refers to flat, wide, layered
clouds.
CLIMATES OF THE WORLD
WORLD CLIMATE PATTERNS
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1. Tropical
2. Dry
3. Mid Latitude
4. High Latitude
5. Highlands
6. Permafrost
TROPICAL CLIMATE
Tropical climates are located near the
Tropics of Capricorn, Tropic of Cancer and
the Equator
1A. Tropical Rain Forest
I. Average temperature of 80 degrees
II. Warm, humid air is saturated with
moisture, produces daily rain
III. Yearly rainfall averages about 80
inches
1B. Tropical Savannahs
I. Dry winters and wet summers
II. In summer, ground is covered with
clumps of coarse grass
III. Found in Africa, Central and South
America, Asia, and Australia
TROPICAL RAINFORESTS
TROPICAL RAIN FOREST
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Despite covering only 2% of our planet's surface, over half of the earth's animal, insect species, and flora live there.
Amazon rain forests produce about 40% of the world's oxygen
One in four pharmaceuticals comes from a plant in the tropical rain forests
1400 rain forest plants are believed to offer cures for cancer
40% of tropical rain forests have already been lost in Latin America and Southeast Asia
Within a four mile square area of a tropical rain forest, you would find:
Over 750 species of trees
1500 different kinds of flowering plants
125 species of mammals
400 species of birds
100 reptiles
60 amphibians
countless insects
150 species of butterflies
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**Only 1% of these species has ever been studied**
The Rainy Tropics (Rain Forest) Breakdown:
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Have no winter
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Broad leaf evergreens, sparsely vegetated floor
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High diversity rates of plant and animal life
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Mostly subsistence farming, slash and burn or shifting agriculture
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Main food types: bananas, plaintan, cassava, taro, coconuts
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Commercial crops: mango, papaya, banana, latex, cacao (chocolate bean), oil palm
Other commercial uses: fishing and timber; much land burned & cleared for livestock grazing
1B. TROPICAL SAVANNAH
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Transition zone between
wet rainfall tropics and
arid lands of tropical
deserts
Strong seasonal rhythms
of rain and drought
Heaviest rains in the
summer, dry a few months
to ½ year
Savanna: Longer dry
season than typical
wet/dry monsoon (mostly
in Africa)
Foods: corn, millet,
sorghum, rice, sugarcane,
pineapple, citrus
Also: cotton and livestock
ranching
TROPICAL SAVANNAHS
2. DRY CLIMATES
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2A. Desert: Dry areas with sparse plant life.
Rainfall less than 10 inches per year.
Daily temperatures vary widely from hot days
to cool evenings.
About 1/3 of the earth’s surface is desert.
Natural vegetation consists of scattered scrub
and cactus and plants that tolerate low
humidity and wide temperature ranges.
Some deserts contain oases, areas of
vegetation and sources of water.
2B. Steppe: dry, treeless grasslands.
Annual rainfall between 10 and 20 inches per
year.
Warm summers and cool winters
Formed between deserts and forests
2A. DESERT STUFF
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World's Largest Deserts
Sahara: 3,500,000 sq. miles North Africa
Gobi: 500,000 sq. miles. Mongolia-China
Kalahari: 225,000 sq. miles. Southern
Africa.
Great Victoria: 150,000 sq. miles.
Australia
Great Sandy: 150,000 sq. miles.
Australia.
GOBI DESERT in Mongolia/China
DESERT
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low relative humidity
and cloud cover
low frequency and
amount of precipitation
high average
temperature
high wind velocities
ATACAMA IN CHILE: SAHARA IN NORTH AFRICA
SAHARA/ATACAMA DESERT
2B. STEPPES
2B. STEPPES
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Deep in continental interiors, far from oceanic
sources of moisture
Many regions in rain shadows of high mountain
ranges
Can extend over large latitude ranges
Winter temperatures mild, summers hot in low
latitudes
Winters frigid and summers cooler at higher
latitudes
Low precipitation, concentrated in summer
Prairies widespread in wetter parts; lush
grasslands
Steppe: very short grasses, sparsely settled,
mostly wide open spaces
Wheat grown in wetter areas, livestock grazing in
drier ones
Prairie =Great Plains in US=Pamapas in
Argentina=Grasslands of Central Asia; all refer to
same climate/vegetation regime
3. MID LATITUDE CLIMATES
Mid latitude climates have variable weather patterns
and changing seasons.
A.Marine West Coast: NW US and Northern Europe,
parts of South America, Africa, Australia and
New Zealand.
1. cool summers and damp winters
2. coniferous trees: cones (evergreen trees)
3. Deciduous trees: broad leaves, change color and
drop their leaves in autumn.
4. Mixed forest: contains both types of trees.
B. Mediterranean:
1.Mild rainy winters and hot sunny summer
2. chaparral: thickets of woody bushes and short
trees.
3. Southern California, parts of Southern Australia
and Southern Europe
C. Humid subtropical climate
1.short, mild winters and nearly year round rain.
2. High humidity levels
4. vegetation: prairies (inland grasslands) and mixed
forest.
D. Humid Continental Climate
1.Located in southern Canada, western Russia, and
northeastern China
2. Longer severe winters and shorter and cooler
summers
3A. MARINE WESTCOAST
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Reach further poleward than Humid Continental
But climates are milder than Humid Cont. at
similar latitudes
Cyclonic westerlies and proximity to ocean
influence precipitation regime--much wetter
Rainfall comes in fall/winter months
Temperate rainforest situation, has huge trees
Crops: fruit trees and year-round grazing situation
ideal for dairy industry, also lots of sheep
3A. MARINE WESTCOAST
3B.MEDITERRANEAN CLIMATE
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Hot/warm and dry summers, rainy winters
Food crops: wheat, olives, grapes, citrus, lavender
Also: sheep and goats which are herded on
unsuitable rocky lands
Vegetation consists of many drought tolerant
plants
Land forms: mountainous near the sea with some
interior coastal plains and interior valleys
1% of land area in this climate, 4% of world
population--very popular place to live
MEDITERRANEAN CLIMATE
3C.HUMID SUBTROPICAL CLIMATE
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Eastern shores of continental land
masses
Transition zone between tropics and
harsher polar latitudes
Long summers, heaviest precipitation
in summer
Several major world river systems fed
by these regions
Forests predominate in mountains;
wetland areas abound in lowlands; flat
to gently rolling land under cultivation
Major crops: cotton, pasture for cattle
in US, rice in East Asia, livestock in
South America and Australia
Region of major urban industrialization
You are currently in this climate zone
3D. HUMID CONTINENTAL
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Winters increasingly severe/summers increasingly cooler
and shorter as one proceeds northward
Most winter precipitation falls as snow
Forests predominately deciduous, especially in US
Coniferous evergreen forest predominant elsewhere
Crops: wheat, corn (mostly for livestock), hay, and
commercial forestry
Agriculture dominates the landscape
3D. HUMID CONTINENTAL
4. HIGH LATITUDE CLIMATES
4A.Subarctic climate: bitterly cold winters and
short and cool summers.
1.
Contains permafrost: permanently frozen
subsoil.
4B. Tundra Climates:: Tundra means “marshy plain.”
1.
North of the subarctic climates
2.
No trees
3.
Vegetation: low bushes, dwarf plants, short
grasses, mosses, and lichens.
4.
Snow and ice covers the surface in winter.
5.
Otherwise, ground surface is wet and spongy.
6.
Located in Antarctica and Greenland
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SUBARCTIC
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Great extremes in seasonal temperatures
Summers short and mild; winters long and severe
Seasonal day/night length radical
Precipitation generally low due to cold air masses inability to
hold moisture
However, low rate of evaporation equate to bog and pond
formation
Covered by vast deciduous forests= boreal forests= taiga
Lower tree growth rate= smaller size, also lower plant/animal
diversity
Poorly suited for agriculture in general, some timber and
pulpwood production
4B. TUNDRA
5. HIGHLANDS
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0-3000 feet above sea level; hot
lands
3000-6500 feet ; moderate
temperate zones with intensive
agriculture: coffee, tea, corn
6500-12000 feet; cool to cold with
hardier crops like corn, wheat,
potatoes, barley
12,000-15,000 feet approaching
tundra and arctic like climate;
some cattle, sheep, and limited
forestry
above 15,000 feet not unlike polar
zone, permanent snow/ice cover
5. HIGHLAND: ROCKIES AND ANDES, FOR
EXAMPLE
PERMAFROST
Below freezing temperatures
Frigid winters
Little precipitation
High winds are common