Unit 6: Weather

1
Weather Climate
2
Weather

• Temporary behavior of atmosphere (whats going on
  at any certain time)
• Small geographic area
• Can change rapidly

3
Weather

• --The study of weather is meteorology
• Forecast is a prediction or estimate of future
  events, especially coming weather
• --Someone who studies weather is called a
  meteorologist

4
Climate

• Long-term behavior of atmosphere (100 years)
• Large geographic area
• Very slow to change

5
Severe weather

•  Refers to any dangerous meteorological phenomena
  with the potential to cause damage, serious
  social disruption, or loss of human life.

6
Temperature

• a measure of how hot or cold something is
  specifically, a measure of the average kinetic
  energy of the particles in an object, which is a
  type of energy associated with motion.

7
Types of Storms
8
Thunderstorms

• Requires a mature cumulonimbus cloud
• Signs
• Sudden reversal of wind direction
• Noticeable increase in wind speed
• Sudden drop in temperature

9
Thunderstorms

• Possible weather
• a. heavy rains (flash floods)
• b. lightning (forest fires)
• c. thunder (frightens animals)
• d. hail (crop damage)
• e. tornadoes
• f. strong, gusty winds

Thunderstorm by Brainpop
10
Lightning Storm

• Cumulonimbus cloud becomes electrically charged
  and ground below has opposite charge

11
(No Transcript)
12

• Lightning stroke flow of current thru air (a
  poor conductor) from the to the
• Lightning can flow from cloud to ground, cloud to
  cloud, and from ground to cloud
• Bright light is caused by glowing air molecules
  heated by the current
• Lightning follows the path of least resistance
  (easiest way to positive)
• Lightning rod offers lightning an easy, safe path
  to the ground ()

13

• Thunder is the shock wave caused by the explosive
  expansion of heated air
• Sound travels _at_ about 1100 ft/sec in air
• 5,280 ft in one mile
• Distance from you to lightning number of
  seconds between seeing the flash and hearing the
  thunder divided by 5. (5,280 ft / 1100 ft/sec
  5 seconds)

14
Types of Lightning

• Streak or bolt
• Single or branched lines of light
• Common in Puget Sound area

15

• Sheet
• a. shapeless flash over wide area
• b. is cloud-to-cloud bolt hidden by the clouds
• c. common in Puget Sound area

16

• Other types of lightning
• a. heat, ribbon, beaded (types of bolt)
• b. ball (only other shape lightning can have)

17
Tornado (a.k.a twister, cyclone)

• Counterclockwise column of rotating air extending
  from cumulonimbus cloud
• Per square foot, is the most destructive
  atmospheric event
• Rated by wind speed (F1 to F5)
• Tornado season April, May, June
• Tornadoes that form over water are called
  waterspouts

18

• Behavior of a tornado is unpredictable
• Typical tornado will
• 1. Occur between 3-7 pm
• 2. Travel 4 miles
• 3. Be 300-400 m wide
• 4. Travel 25-40 mi/hour
• 5. Have wind speeds up to 300 mi/hr
• 6. Produce extremely low pressure
• 7. Be dark due to debris picked up

Tornado by Brainpop
19

• Lie flat in nearest ditch, etc.
• At home
• a. open windows, doors
• b. seek shelter in basement or under heavy table
  in middle of house

On the trail of a tornado
20
Tropical Cyclone

• Nicknames
• 1. U.S.A. hurricane
• 2. SE Asia, Japan typhoon
• 3. Australia willy-willy

21
Tropical Cyclone

• Rated by wind speed (category 1 to 5)
• Starts and grows over warm ocean water
• Composed of bands of thunderstorms spiraling
  counterclockwise around a low pressure center

22
Characteristics

• Several hundred miles wide
• Last many days (even weeks)
• Winds from 74-200 mi/hr
• Contains an eye
• Small region of low pressure
• Surrounded by highest winds
• Calm, peaceful, sunny weather
• Last for about 1 hour as hurricane passes by

Hurricances by Brainpop
23
Safety Rules

• Prepare for high winds
• Prepare for flooding (greatest source of damage)
• Up to 20 in. of rain
• Flooding by coastal water
• 3. Prepare for thunderstorms
• 4. Have on hand stored food, water, blankets,
  candles, matches, radio, etc.
• 5. Seek shelter

Hurricanes Clip
24
Relative Humidity

• Measure of the amount of moisture in the air
  compared to what the air could hold
• How full of water the air is
• Expressed as
• 100 relative humidity saturated air

25
Relative Humidity

• Controlled by temperature
• 1. Warm air holds more moisture than cool air
  (more space for water vapor between air
  molecules)
• 2. As air warms, relative humidity decreases
• 3. As air cools, relative humidity increases

26
What Factors Affect Weather Climate?

1. The Sun
2. The Water Cycle
3. The Atmosphere
4. The Ocean

27
How Does the Sun Affect Weather?

• It warms the atmosphere oceans
• It creates climate zones
• It keeps the water cycle going
• It affects weather patterns

28
The Water Cycle

• All the water on the planet is recycled in this
  manner!

29
Parts of the Cycle

• EvaporationWater going from a liquid to a gas
  (gains energy from the sun)

30
Parts of the Cycle

• Transpirationevaporation of water from/out of
  plants.

transpiration
31
Parts of the Cycle

• CondensationWater going from a gas to a liquid
  (cools or loses energy)
• When this happens in the atmosphere, CLOUDS form.

32
Parts of the Cycle

• Precipitationwhen water falls out the
  atmosphere. Forms when the water droplets in
  clouds become too heavy to stay up.

33
Precipitation

• Liquid water rain
• Frozen water snow or sleet or hail

34
The Water Cycle
Water Cycle by Brainpop
35
Water Cycle Advanced by Brainpop
36
How does the atmosphere affect weather?

• The atmosphere is a mixture of gases that
  surrounds the Earth
• Has five different layers each has different
  properties
• Well label them in just a minute
• Air Temperature and Pressure change with altitude
• Weather occurs in the layer closest to Earth
  (troposphere)

37
Write in the labels!
Exosphere
Thermosphere
Ionosphere
Mesosphere
Ozone layer
Stratosphere
Troposphere
38
(No Transcript)
39
(No Transcript)
40
(No Transcript)
41
Exosphere - the outermost layer of the Earth's
atmosphere, where atmospheric pressure and
temperature are low.Ionosphere - the atmospheric
layer between the mesosphere and the exosphere
it is part of the thermosphere.Mesosphere - the
atmospheric layer between the stratosphere and
the ionosphere.Stratosphere - the atmospheric
layer between the troposphere and the mesosphere.
The stratosphere is characterized by a slight
temperature increase with altitude and by the
absence of clouds.Thermosphere - the layer of
the atmosphere located above part of the
ionosphere (starting at the coldest part of the
atmosphere) and below outer space it consists of
the exosphere and part of the ionosphere.Troposph
ere - the lowest layer of the Earth's atmosphere.
The weather and clouds occur in the troposphere.
42
Air Masses

• body of air with a certain temperature and
  moisture level
• Can be warm or cold
• Can contain a lot of moisture or not a lot of
  moisture

43
Fronts

• places where air masses meet
• 4 Types Warm, Cold, Occluded, Stationary
• Each kind can bring different kinds of weather

44
Occluded Front
Stationary Front
45
(No Transcript)
46
Science Saurus 221/222 Reading a Weather Map
Worksheet
47
How does Air Pressure affect weather?

• How much the earths atmosphere is pressing down
  on us
• Measured with a BAROMETER
• If it CHANGES, then new weather is on the way
• Falling Air Pressure stormy weather coming
• Rising Air Pressure fair weather coming
• Steady Air Pressure no change is coming

48
Winds created from differences in air pressure

• Moves from areas of HIGH to LOW pressure
• Greater the difference in pressure, the FASTER
  the wind blows
• Measured with wind vanes and anemometers or you
  can estimate with the Beaufort Wind Scale

ScienceSaurus 224/225
49
Beaufort Wind Scale
50
Global Winds

• Thousands of kilometers long can cause weather
  to move in different directions
• Jet stream, prevailing westerlies, doldrums,
  horse latitudes, trade winds

Big Winds Blowin Worksheet Science Saurus
Section 217
51
Global Winds

• Caused by the temperature difference in different
  regions
• Hot Tropical Regionscauses air to rise
• Cold polar Regionscauses air to sink

52
Global Winds

• Also affected by Earths Spin
• Coriolis Effect causes winds to curve to the
  right in the N. Hemisphere to the left in the S.
  Hemisphere

53
Big Winds Blowin Worksheet
54
Dew Point

• Temperature at which the air is saturated (100
  relative humidity)
• Several events can occur when the dew point temp.
  is reached
• 1. If dew point temp. is above freezing
• a. water vapor condenses as liquid
• b. dew will form on surfaces

55
Dew Point

• c. cloud droplets will form in air
• 2. If dew point temp. is below freezing
• a. water vapor condenses as a solid
• b. frost on surfaces
• c. snow (or hail) in the air

56
Humidity by Brainpop

• . What single factor controls humidity?
• . What temperature air can hold the most water
  molecules?
• . What causes water to evaporate into the
  atmosphere?

57
Rainbows

• Caused by sunshine on raindrops
• White light (all colors) is refracted (bent) into
  colors as it enters and exits the drop
• To see a rainbow you must have the sun behind you
  and raindrops in the air
• Diagram

58
Rainbow by Brainpop
59
How does the Ocean affect weather?

• Ocean currents affect the temperature of the land
  they pass by
• Cold ocean currents cooling effect
• Warm ocean currents warming effect
• Temperature changes affect pressure which then
  creates WINDS
• Winds blow this cooling or warming effect over
  the land
• http//earth.rice.edu/MTPE/hydro/hydrosphere/topic
  s/Ocean_Atm_Circ_ElNino.mov

60
http//www.wunderground.com/MAR/