Download Weather, Climate, and Biomes

Unit 4 - Weather, Climate,
and Biomes
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What is Weather?
 Definition:
- the state or condition of the variables
of the atmosphere at any given
location for a short period of time
- in fact, meteorology is the study of
the weather
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Where does Weather
Occur?
 Remember: Weather occurs in the
layer of the atmosphere called the
TROPOSHERE!!!
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How do we Measure the
Weather Variables?
 Air Pressure:
 Caused by the weight of the atmosphere,
so air pressure is the greatest at Earth’s
surface and decreases as you go higher in
the atmosphere (think of diving deep in
the ocean).
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How do we Measure the
Weather Variables?
- Measuring air
pressure:
- Measured using a
barometer
- Barometers measure
the effect of weight
from the atmosphere
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2 Factors that Affect
Air Pressure
1. Temperature: Measured with a
thermometer in degrees Celsius.
Weather Shelter – where
official temperature
readings are taken
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Factors that Affect Air
Pressure
 Temperature continued:
 Cool air is more dense than warm air.
 If air is warmed, it becomes less
dense and air pressure decreases
 If air is cooled, it becomes more
dense and air pressure increases.
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2 Factors that Affect
Air Pressure
2. Altitude:
 Air pressure decreases as you go up
(when altitude increases).
 This is due to the fact that there is less
of the atmosphere above you pushing
down.
 This is why people who climb tall
mountains carry oxygen tanks with
them.
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How Air Pressure Affects a
Rising Balloon
 http://www.classzone.com/books/earth_science/t
erc/content/visualizations/es1901/es1901page01.cf
m?chapter_no=visualization
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As the warm air rises, it
becomes cooler and
more dense
Cool air
is sinking
– more
dense
Warm air
is rising –
less dense
Cool air takes the place of
the rising warm air-to fill
space
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What is Wind?
WIND –
 horizontal movement of air parallel to Earth’s
surface
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What Causes the Wind?
 wind is created by the uneven heating
of Earth’s surface
 uneven heating causes differences in
air pressure
 wind will always blow from areas of
high pressure to areas of lower
pressure
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Measuring the Wind
Wind Measurement requires a size and direction to
describe it
Ex. 70 mi/hr SE wind
- wind is named for the direction from which it
came from
Ex. A south wind (heading north but came
from the south)
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Measuring the Wind
Wind continued…
The speed of wind is measured using an
anemometer
- measured in mi/hr or knots (boats)
The direction of the wind is
determined using a weather vane
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Wind Facts
Wind continued…
 Wind is responsible for creating waves in the
ocean because energy from the wind is
transferred to the water
 Jet streams - areas of very fast winds in the
upper atmosphere that separates warm air
masses from cool air masses.
 Affects where weather and storms flow.
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Wind Facts:
Jetstream
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Jet stream Facts
 During World War II the Japanese used the air
stream to fly balloons at 30,000 feet across the
Pacific to the USA.
 The jet stream is the reason why transatlantic flights
are quicker going from America to Europe.
 They can be as fast as 315mph.
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Factors of Weather
CLOUDS
 Masses of water vapor combined with
dust particles in the atmosphere
 Takes about 1 million cloud droplets to
make a single raindrop
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Water Cycle
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How do Clouds Form?
1. Water evaporates from the surface of Earth into the
atmosphere (liquid changes to a gas).
1. Water vapor molecules condense on dust particles
(gas changes to a liquid).
1. When droplets become heavy enough, the water
falls toward Earth as precipitation.
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4 Basic Cloud Types
1) Cumulus - Look like a heap
of cotton balls or whipped
cream; summertime;
typically no precipitation
1) Stratus - Clouds that look
like a flat blanket in the
sky; low rain clouds; cover
whole sky
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4 Basic Cloud Types
3) Cirrus - Look like curls of white
hair; fair-weather cloud;
whispy; look like airplane
tracks
4) Cumulonimbus - cotton-like
clouds that have built up in the
middle or high part of the
atmosphere; tall, deep, & dark;
bring lightening, heavy rain,
and severe weather
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Name that Cloud
Stratus
Cumulonimbus
Cirrus
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Cumulus
Precipitation
PRECIPITATION falling of liquid or solid water from clouds
toward the surface of Earth
 to occur, ice crystals or water droplets in
clouds must come together to become big
enough so that they will fall under the
influence of gravity
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Precipitation
Forms of precipitation include:
rain
snow
hail
drizzle
sleet
freezing rain
- rain gauge: used to measure liquid precipitation;
measured in inches or cm
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Identify the Form of
Precipitation
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Precipitation
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Severe Weather
Thunderstorms
 Heavy rain & electricity (lightening) form from
cumulonimbus clouds
 Lightening is electricity that results from charges
when water vapor molecules collide with each
other
 Lightening bolts are hot! (30,000-50,000°F)
 This heats air around it so fast that the air
expands sending out vibrations & shock waves
we hear as sound (thunder)
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Thunderstorms continued
 At any time, over 2,000
thunderstorms are
happening on Earth
 Hail can come from T
storms where water
encounters below
freezing temps
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Severe Weather
Tornados
 Rapidly rotating extremely low pressure
funnel that hangs down from thunderstorm
clouds towards Earth’s surface
 True tornados touch Earth’s surface
 Narrow & at least 100 ft. wide
 Can reach wind speeds of 350 mph
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Tornados continued
 Not clear how tornados
are formed except
formed when 2 air
masses with huge
temperature differences
from thunderstorm
clouds collide
 Low air pressure
vacuums up
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Measuring Tornado
Strength
 Measured using the
Fujita Scale.
 From F0-F2 is moderate
to significant – winds
are 40-157 mph. Can
tear off roofs of houses.
 From F3-F4 is a
devastating tornado 158
to 260 mph and can
level houses and throw
cars.
 F5 is an incredible
tornado 261-318 mph.
Houses lifted off
foundations, bark
pulled off trees.
 F6 is inconceivable –
never been achieved
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Tornado Videos
 http://video.nationalge
ographic.com/video/pl
ayer/environment/env
ironment-naturaldisasters/tornadoes/tor
nado-montage.html
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Severe Weather-Hurricanes
Hurricanes
 Large rotating, lowpressure storms
 Develop late in
summer, early fall in
Atlantic Ocean between
South America and
Africa (where waters
are very warm)
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Severe Weather-Hurricanes
 Evaporation of warm water
 Condensation – releases energy for the
storm
 All low pressure systems rotate
counterclockwise. (in the northern
hemisphere)
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Severe Weather-Hurricane
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Rating Hurricane Strengths
 http://www.nhc
.noaa.gov/about
sshs.shtml
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Other Forms of Severe
Weather
 Tsunami
 Series of water waves
caused by large body
of water (ocean) that is
rapidly displaced
 Means harbor wave (in
Japanese)
 Caused by:
earthquakes, volcano
eruptions, underwater
explosions (nuclear
devices), etc.
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Climates
Define Climate:
- long term weather pattern of an area
including precipitation, temp, and wind
- causes are solar radiation to an area
- recall, the Earth has seasons because of the
23 ½ ° tilt which means the amount of solar
radiation to hit the Earth varies depending
upon the Earth’s location to the Sun
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Types of Climate
1. Tropical climate - constant high temps and
rain
2. Dry climates - 30% of Earth’s land area; hot
temps, low precipitation, vegetation scarce;
high solar radiation, few clouds
3. Mild climates - warm, muggy weather in
summer and cool weather in winter
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Types of Climate
4. Continental climates - area where tropical &
polar air masses collide; rapid & violent
changes in weather; summer & winter
temps are extreme
5. Polar climates - coldest regions on Earth;
constant cold; precipitation is low; cold air
cannot hold as much moisture
In these climates, there exist systems of animals
and vegetation that thrive in that temperature range
called BIOMES
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Biomes
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List of World Biomes
Biome
Picture
1. Tropical Rainforest
2. Tropical Dry Forest
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List of World Biomes
Biome
Picture
3. Tropical Savannah
4. Desert
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List of World Biomes
Biome
Picture
5. Temperate Grasslands
6. Temperate Forests
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List of World Biomes
Biome
Picture
7. Northwestern
Coniferous Forest
8. Taiga (Boreal Forest)
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List of World Biomes
Biome
Picture
9. Tundra
10. Estuary
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List of World Biomes
Biome
Picture
11. Saltwater
12. Freshwater
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