Unit 5 Weather and Climate

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Transcript Unit 5 Weather and Climate

Unit 6 Weather and Climate
Unit Essential Question: How does
the sun interact with the Earth to
produce weather and climate?
Concept #1: Weather and Climate
LEQ: How do weather and climate differ?
What is
weather?

In simple terms, weather is what is taking place in
the air around you at a certain place and time.

Weather takes place in the troposphere, which is
the lowest layer of Earth’s atmosphere.

The atmosphere is the envelope of gases that
surrounds the planet.
Layers of
Earth’s
Atmosphere
Important facts to remember about weather:

It is powered by the sun.

It changes from day to day.

The daily condition of the
atmosphere, or weather, of a
particular area is based on:
Temperature
(Heat)
Moisture
(humidity, clouds,
precipitation)
Wind
(moving air, air
masses, fronts)

Scientist who predict the
weather are called
meteorologists.
What is climate?
 Climate
is the name for the general
conditions of temperature and
precipitation for an area over a long
period of time.
 The
climate of a region is described
according to two basic factors:
temperature
precipitation
Factors that affect temperature of a
region’s climate:
 Four
natural factors that affect the
temperature at a particular location:

Latitude

Altitude (elevation)

Distance from large bodies of water
Ocean
Currents
Factors that affect the
temperature of a region’s
What is latitude?
climate: Latitude
 It
is the measure, in degrees, of the distance
north and south of the equator.
How does latitude affect climate?
 Areas
close to the equator, or zero degrees
latitude, receive the direct rays of the sun.
These direct rays provide the most radiant
energy.
 Areas
near the equator have a warm climate.
Polar regions have a cold climate.
Factors that affect the
temperature of a region’s
climate:
 BasedLatitude
on Latitude, Earth’s surface
can be divided into three main
temperature zones (see map on
the following slide):
Tropical Zone
Temperate Zone
Polar Zone
Map of world
temperature zones
Earth’s
temperature
zones:
Tropical Zone

Location: area near the equator, between 23.5
degrees north and 23.5 degrees south.

Sunlight: receives the most all year round

Climate: warm
Earth’s
temperature
zones:
Temperate
Zone

Location: between the tropical and polar zones.

Sunlight: strikes it more directly

Climate: ranges from hot or warm in the summer;
cool or cold in the winter
Earth’s
temperature
zones:
Polar Zone
Location: extends from 66.5 degrees north to 90
degrees north AND 66.5 degrees south and 90
degrees south.
 Amount of sunlight: always strikes at a lower angle.
 Climate: cold

Factors that affect climate:
 Elevation
Elevation, or altitude, is the distance above sea




level.
As elevation increases, the air becomes less dense ,
has fewer gas molecules, and temperature decreases.
Mountain ranges, can play an important role in the
amount of precipitation an area receives.
A mountain range acts as a barrier to prevailing
winds. The windward side of a mountain has a wet
climate.
On the leeward side, relatively dry air moves down
the side of the mountain, which results in very little
precipitation on the opposite side.
Factors that affect the temperature of a
region’s climate: Large bodies of water
 Large
bodies of water, such as lakes
and oceans, can affect the
temperature of an area because the
temperature of the water body
influences the temperature of the air
above it.
 Temperatures of nearby lands are
less extreme.
Factors that affect the temperature of a
region’s climate: Ocean Currents

Ocean currents help transfer heat to the atmosphere.

Some warm ocean currents move water from the equator
towards the poles and warms the air above it. The warm air
moves over to the nearby land.

At the same time, cold currents bring cold water from the
polar zones towards the equator. As it moves, it brings cool
air.

Marine climates are influenced by ocean currents.

The Gulf Stream is an ocean current that carries warm
water along the eastern coast of the United States.

The California Current travels toward the equator carrying
cold water along the west coast of the United States.
Map of Ocean
Currents
Factors that affect the amount
of Precipitation an area
receives impact the climate of
that region.
 Prevailing
Winds: directional winds that
usually blow in a region such as the
prevailing westerlies and the polar
easterlies, which affects weather in the
United States.
 Presence
 Seasonal
of Mountains
Winds: sea and land breezes
over a large area that change direction
with the season such as monsoons.
Prevailing winds affect the amount
of precipitation
1. Weather patterns are
influenced by movement of air
masses.
2. Movement of air masses rely on
prevailing winds, which are the
directional winds that move in
a particular region.
The temperature of the air mass
determines the amount of moisture
it carries. Warm air masses hold a
lot of moisture while cold air
masses do not.
4. The direction from which the air
mass comes will also determine the
amount of moisture it carries.
Winds blowing inland from oceans
and lakes carry more water vapor
than winds that blow over land.
3.
Mountain ranges affect the amount
of precipitation
1. A mountain range acts as a barrier to
prevailing winds. The windward side of a
mountain has a wet climate.
2. On the leeward side, dry air
moves down the side of the
mountain resulting in very little
precipitation on the leeward side.
Seasonal winds affect the amount of
precipitation
1. Monsoons happen during the
summer in South and Southeast Asia
when the land gradually gets warmer
than the ocean.
2. Sea breezes blow inland constantly
bringing to the land warm, humid air.
3.As the warm air rises over land, it
cools, condenses to clouds, and
produces heavy rains.
4. Monsoon regions receive very little
rain in the winter because the land
cools becoming colder than the ocean.
5. Since wind moves from areas of
high pressure (cold wind from the
land) to areas of low pressure (warmer
ocean), it carries very little moisture.
Scientists classify Earth into six
broad climate regions based on
temperature and precipitation
received in that region:
• Tropical Rainy
•Dry
•Temperate Marine
•Temperate Continental
•Polar
•Highlands
Map of Earth’s Climate Regions:
Tropical Rainy Climate Region




Temperature:

Temperate wet: 18 degrees Celsius or higher

Temperate dry: always hot
Precipitation:

Temperate wet: heavy rainfall year-round, about 72 cm

Temperate dry: heavy rainfall in the wet season, more than 59 in.
Usual Weather:

Temperate wet: hot and humid

Temperate dry: has distinct dry and wet seasons
Places: Temperate wet – windward side of Hawaiian Islands:
Temperate dry - southern tip of Florida and Makindu, Kenya
Dry Climate Region

Temperature: may be hot or cold

Precipitation:
 Semiarid
 Arid

– less than 25 cm
Usual Weather:
 Semiarid
 Arid

– less than ½ inch (about 25-50 cm) per year
– little rainfall, very dry
– very dry, little rainfall
Places:
 Semiarid
 Arid
– Great plains in the United States
– Parts of California
Temperate Marine Climate Region

Temperature: Averages 10 degrees Celsius or higher in the warmest months,
and between -3 degrees Celsius in the coldest months.

Precipitation: Moderate all year in marine west coast climate, about 16-68
inches per year.

Usual weather: Three sub-types of Temperate Marine Climate –


Mediterranean: warm, dry summers; rainy winters

Humid subtropical: hot summers, cool winters, hurricanes,
thunderstorms.

Marine west coast: mild winters, cool summers.
Places:

Mediterranean: places near the Mediterranean Sea, southern
California

Humid subtropical: southeastern United States

Marine west Coast: northern California to southern Alaska
Temperate Continental Climate Region

Temperature: Average is 10 degrees Celsius or higher in the warmest month,
and -3 degrees Celsius in the coldest month.

Precipitation:



Humid continental: moderate amount year-round, up to 40 inches

Subarctic: light precipitation mainly in the summer
Usual weather:

Humid continental: hot, humid summers; cold winters

Subarctic: short, cool summers; long, cold winters
Places:

Humid continental: Northern Hemisphere only, northeastern part of the United
States.

Subarctic: Parts of Alaska, Canada, and Russia
Highland Climate Region

Temperature: Falls as altitude increases.

Precipitation: Increases as altitude
increases.

Usual Weather:


Climate in the foothills are similar
to semi-arid climate.

Higher up in the mountains would
be similar to subarctic climate.

Above the tree-line would be
similar to tundra climate.
Places:

Mt. Rainier in Washington State

Rocky Mountains
Polar Climate Region




Temperature:

Tundra: Average is below 10 degrees Celsius in the warmest month

Ice Cap: Average is at or below zero degrees Celsius (below freezing!)
Precipitation:

Very little, mostly snow

Dry because cold air holds very little moisture.
Usual Weather:

Tundra: short, cool summers; bitterly cold winters.

Ice Cap: intense cold with dry air
Places:

Tundra: Northern Alaska, Canada, Russia

Ice Cap: Greenland, Antarctica
Outside the tropics, most regions
have four distinct seasons all year
long: winter, spring, summer, and fall
(autumn).
Seasons are not related to the
distance between the Earth and the
sun.
The tilt of Earth’s axis as it travels
(revolves) around the sun is the cause
of the seasons.
The seasons change as the amount of
energy (sunlight) each hemisphere
receives from the sun changes.
http://www.classzone.com/books/earth_science/terc/content/vi
sualizations/es0408/es0408page01.cfm?chapter_no=04
S6E2. Students will understand
the effects of the relative
positions of the earth, moon and
sun.
c. Relate the tilt of the earth to the
distribution of sunlight throughout
the year and its effect on climate.
Concept #2
LEQ #1:How does heat affect
changes in weather patterns?
LEQ #2: How does heat cause
changes in air masses?
S6E4. Students will understand how the distribution of land and oceans
affects climate and weather.
a. Demonstrate that land and water absorb and lose heat at different rates and
explain the resulting effects on weather patterns.
b. Relate unequal heating of land and water surfaces to form large global wind
systems and weather events such as tornados and thunderstorms.
c. Relate how moisture evaporating from the oceans affects the weather patterns
and weather events such as hurricanes.
Today’s video review questions:
1.
What causes the uneven heating of Earth’s surface?
2.
What effect does the uneven heating of Earth’s
surface have on the weather?
3.
How does the uneven heating of Earth’s surface
affect the air above it?
4.
Which type of heat transfer (conduction,
convection, or radiation) circulates heat in the
atmosphere as well as in the oceans?
5.
How does wind affect weather?
6.
What is the relationship between air pressure and
wind?
Temperature is the measure of
motion in particles.
The faster the air particles are
moving, the higher (hotter,
warmer) the temperature.
The slower, the lower (colder,
cooler) the temperature.
Movement of heat (heat transfer)
in the atmosphere causes
temperatures to change, wind to
blow, and precipitation to fall.
How does the uneven heating
of Earth’s surface cause wind
and affect weather patterns?
How is wind created and what
affect does it have on weather?
Warm
air is less dense than cool
air so rises, and cool air tends to
sink. As warm, moist air rises,
less air pushes down on the area
below it. This creates an area of
low pressure.
As
cool, dry air sinks, more air
pushes down on the area below it.
This creates an area of high
pressure.
Air moves from an area of high
pressure to an area of low
pressure. This movement of air is
called wind.
Important points to remember
about wind and air pressure:
 Air always moves from an area of high
pressure to an area of low pressure.
 Air
pressure decreases as altitude
increases.
Changes
in air pressure causes
changes in weather.
The greater the pressure
difference between two areas, the
faster the air moves and the harder
the wind blows.
Local Winds: Sea and Land Breezes
Global Wind Belts are caused by
global convection currents and other
factors. Such as the Coriolis Effect.
These affects a larger area than
local winds.
• Doldrums
• Horse Latitudes
• Trade Winds
• Prevailing Westerlies
• Polar Easterlies
Compare and Contrast Types of Winds
Local:
Unequal heating
over a small area
Global:
Blow from specific directions over
long distances
Sea BreezeCool air from water
moves to take warm air’s
place on land
Doldrums
Weak winds (down in the dumps)
Land BreezeLand cools off faster than
water. Cooler air from
land moves to take warm
air’s place on water.
Horse Latitudes
At about 30 degrees north and south latitude,
sailors dumped the horses out of the boats.
Trade Winds
Blows toward the equator
Prevailing Westerlies
Winds towards the poles. These winds play a large
part in our water.
Polar Easterlies
Away from the poles. These winds play a large part
in our weather.
Jet Streams
Hundreds of kilometers
wide but not deep. They
blow at speeds of 200400km/hour. You can
travel faster going from
west to east if your plane
gets in a jet stream.
Monsoons
Unequal heating of land
and water. Supply
needed rain by crops.
Occur in South and
Southeast Asia
Concept #3
LEQ: How does moisture affect
weather patterns?
S6E4. Students will understand how the distribution of land and oceans
affects climate and weather.
a. Demonstrate that land and water absorb and lose heat at different rates and
explain the resulting effects on weather patterns.
b. Relate unequal heating of land and water surfaces to form large global wind
systems and weather events such as tornados and thunderstorms.
c. Relate how moisture evaporating from the oceans affects the weather patterns
and weather events such as hurricanes.
How does moisture affect weather patterns?
Water moves from the air to land and back again through a
process called the water cycle. The cycling of water in and
out of the atmosphere plays an important role in determining
Condensation
• The water vapor rises into the air, cools, and
condenses into tiny droplets of water.
• The drops of water come together to form
clouds.
Water Cycle
Evaporation is when a
liquid changes to a
gas.
The sun’s heat makes
water evaporate into
water vapor.
Precipitation
The water drops
become heavy and
fall as rain, sleet,
snow, or hail.
The rain falls or snow melts
and flows to rivers, lakes, and
oceans.
Precipitation
 Water
that falls from the clouds
 Air
temperature determines the form
of precipitation that falls
4
main types of Precipitation: Rain,
Sleet, Snow, and Hail
Types of Precipitation
Rain
Sleet
Snow
Hail
Clouds
 Clouds
form when warm, moist air rises
and cools and then condenses around
particles like salt crystals, dust from soil,
and smoke.
 They
generally form in areas of low
pressure and along fronts.
 Three
main types are cirrus, cumulus,
and stratus.
Cloud Formation
Cirrus Clouds
Cirro- means
“curled” or
“feathery”
 Form highest in the
sky; are made up of
ice crystals; and
appear as curls,
tufts, or wisps.
 Usually signal the
end of clear
weather.

Cumulus Clouds

Cumulo- means “heaped” or
“piled”

Cottony clouds with flat,
usually gray bases, and
puffy, bright tops.

Usually signal good weather,
but if atmosphere is
unstable, can build into
towering clouds that
produce showers and
thunderstorms.
Stratus Clouds

Strato- means “layer-like” or “sheetlike.”

Low-lying, dull-colored clouds that form
in layers or sheets.

Usually bring drizzling rain or lightfalling snow.
Alto

A prefix meaning
“middle range of
clouds “

Used to describe
clouds that lie
from 6,50018,500 ft. (1,9805,640m).
Altocumulus
Altostratus
Nimbo
A rain cloud
Nimbostratus
Other Cloud Types
Cirrocumulus
Stratocumulus
Cirrostratus
Cumulonimbus
Humidit
y
The amount of water vapor present in the air.
It depends on the temperature and other factors.
Relative Humidity -is a measure of the amount of
water vapor present in the air compared to the
amount needed for saturation at a specific
temperature.
Progress Check:
• What
factors cause
condensation?
•
Explain in your own words how
temperature, humidity, and
dew points are related.
•
What are the three main types
of clouds?
Air Masses and Fronts
Air mass - a large body of air that has
properties similar to the part of the
Earth’s surface over which it develops.
Air masses are classified according
to two characteristics:
1.Temperature – described as
warm (tropical) or cold (polar)
depends on the temperature of
the Earth’s surface below it.
2. Moisture – described as humid
or dry, depends on whether it
forms over water or land
Four major types of air masses that
influence weather in North America:
1. Maritime Tropical – moist, warm air mass that
form along the tropics and have low air pressure
2. Continental Tropical – dry, warm air masses that
form over land that have less exposure to moisture
from bodies of water.
3. Maritime Polar – moist, cold air masses that
form north 50 degrees latitude and south 50
degrees latitude.
4. Continental Polar – dry, cold air masses that
form over land.
Air Mass Map
What is a front?
www.phschool.com (fronts animations: web code cfp-4031)
Front - A boundary between two air masses of different
density, moisture (humidity), or temperature.

Where unlike air masses meet and collide, storms develop
and other weather changes occur.

The type of front that develops depends on the
characteristics of the air masses and how they are moving.

There are four main types of fronts:

Cold Front

Warm Front

Stationary Front

Occluded Front
A Cold Front occurs when a cold air mass
pushes under a warm air mass, forcing
warm air to rise.
A Warm Front occurs when a warm air mass
meets and glides up over a cold air mass.
An Occluded Front occurs where a warm air
mass is caught between two cooler air
masses.
A Stationary Front occurs where warm and
cold air masses meet, but neither one
moves.
Storms: develop where two
air masses meet.

A storm is a violent disturbance in Earth’s
atmosphere.

It is caused by changes in air pressure, which
causes rapid air movement.

There are several types of severe storms:
 Thunderstorms
 Tornadoes
 Hurricanes
Thunderstorms

A thunderstorm has rain,
thunder, and lightning.

When we see big, thick,
dark cumulus clouds,
we might expect thunder
and lightning to come.

Lightning produces light and heat - called energy.

When the air is heated that quickly, it expands (gets
bigger) and then contracts (gets smaller). When the
air expands and contracts, it creates an explosion
called THUNDER.

Lightning safety – Stay indoors away from doors and
windows. Do not use the telephone. Take off head
sets. Turn off, unplug, and stay away from
appliances, computers, power tools, & TV sets.
Hurricane

A hurricane begins over warm
ocean waters and has winds
that are more than 74 mph.

It has strong winds, high ocean
waves, and lots of rain.

It causes floods and destroys
many homes and buildings.

The hurricane season begins
June 1 and ends November 30.

Stay indoors, in the center of
your home, in a closet or
bathroom without windows.
Tornado

A tornado is a funnel-shaped
cloud that spins very fast.

It has very strong winds that
can destroy many houses and
buildings.

It picks up debris or buildings
by its swirling winds.

Tornado safety – Stay inside
away from windows, doors
and outside walls. Cover your
head and body to protect
yourself from flying objects.