UNIT 4

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UNIT 4 WEATHER DYNAMICS
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BOOK SECTIONS

• Chapter 13
• Getting started, 13.1, 13.2, 13.3, 13.4, 13.6,
  13.8, 13.9, 13.1, 13.13,
• Chapter 14
• Getting started, 14.2, 14.3,14.5, 14.6
• Rest of Chapter 14, 15, 16
• Class Oral Presentations

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INTRODUCTION

• WHY IS A STUDY OF WEATHER IMPORTANT TO OUR LIVES?
• PLANNING AHEAD
• (ex travel, recreational activity, work)
• SAFETY AND ENGINEERING
• (ex creating weather-resistant structures)
• ECONOMY
• (ex careers in meteorology and science)
• SCIENCE
• Researching weather patterns and interactions

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WHAT FACTORS AFFECT OUR WEATHER PATTERNS?

• GLOBAL
• Global Warming
• Ocean Currents
• Air Masses
• Seasons/Angle of Sunlight
• Earths rotation
• Latitude
• Longitude
• Air Pressure

• LOCAL
• Elevation/Topography
• Proximity to Water
• Distance Inland
• Vegetation
• Cloud Cover

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SOME GENERAL TERMS

• WEATHER DYNAMICS is the study of how water and
  air cause weather patterns.
• WEATHER
• The short-range forecast daily conditions.
• Ex temperature, precipitation, wind,
  humidity, UV
• CLIMATE
• Long-term seasonal trends averaged from annual
  data
• Ex In the Atlantic Canada Climate region,
  winters are cold and summers are Warm

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GLOBAL WEATHER PATTERNS

• 3 MAIN PARTS OF THE EARTH influence GLOBAL
  WEATHER
• ATMOSPHERE ? AIR
• HYDROSPHERE ? WATER
• LITHOSPHERE/GEOSPHERE ? LAND

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SOME GLOBAL WEATHER TERMINOLOGY

• GEOGRAPHY
• The study of oceans, continents, countries, ocean
  currents, and air currents.
• LONGITUDE
• Vertical lines on maps/globes that show our
  position EAST or WEST of the PRIME MERIDIAN line.
• LATITUDE
• Horizontal lines on maps/globes that show our
  position NORTH or SOUTH of the EQUATOR

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PRIME MERIDIAN, GREENWICH, ENGLAND
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Some Special Latitude Lines

• ARCTIC CIRCLE
• 66.5oN, most Northern latitude to receive suns
  rays on December 21st
• ANTARCTIC CIRCLE
• 66.5oS, most Southern latitude to receive suns
  rays on December 21st
• TROPIC OF CANCER
• 23.5oN, most Northern latitude to receive suns
  vertical rays on June 21st
• TROPIC OF CAPRICORN
• 23.5oS, most Northern latitude to receive suns
  vertical rays on June 21st

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Some Special Latitude Lines. . .
Be able to identify these on a test!
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Latitude Lines and Seasons
On December 21st, NOTICE how the NORTHERN
HEMISPHERE is TILTED AWAY from the SUN (Winter)
and the SOUTHERN HEMISPHERE is TILTED TOWARD the
SUN (Summer)
On JUNE 21st, NOTICE how the SOUTHERN HEMISPHERE
is TILTED AWAY from the SUN (Winter) and the
NORTHERN HEMISPHERE is TILTED TOWARD the SUN
(Summer)
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GLOBAL REGIONS

• POLAR REGION
• Area between the Arctic Circle Line and North
  Pole, and Antarctic Circle Line and South Pole
• MIDLATITUDE REGION
• Area between the Circle Lines and the Tropics
  Lines
• TROPICAL REGION
• Area between the two Tropics Lines

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LATITUDE LINES AND GLOBAL REGIONS
N POLE
POLAR REGION
ARCTIC CIRCLE
MIDLATITUDE REGION
TROPIC OF CANCER
TROPICS REGION
EQUATOR
TROPIC OF CAPRICORN
ANTARCTIC CIRCLE
S POLE
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HOMEWORK!!!

• Questions 1, 2, 4, 8 on page 502!!!

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HOW IS ENERGY TRANSFERRED?

• As you already know, all of the earths energy
  initially comes from the SUN, with its steamy
  average temperature of 15,000,000oC, and its
  energy output of 3.83 x 1023 kJ/s.

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HOW IS ENERGY TRANSFERRED?

• Weather and climate patterns are based on the
  transfer of energy between and within air masses
  and water bodies.
• 4 METHODS OF ENERGY TRANSFER
• RADIATION
• CONDUCTION
• CONVECTION
• ADVECTION

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1. RADIATION

• The transfer of energy in the form of WAVES.
• This type of energy can travel through A VACUUM
  (empty space) as opposed to through a MEDIUM (s,
  l, g).
• Examples of radiation waves include
• UV, visible light, gamma rays, etc.

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RADIATION . . .
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ELECTROMAGNETIC SPECTRUM

• The complete set of radiation waves that can
  travel through empty space.

Also See Figure 1 on page 505
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2. CONDUCTION

• The transfer of energy through the collision of
  particles through solids.
• Occurs in conductive materials (i.e., metals).
• Small role in weather, bigger role in surface
  heating.

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CONDUCTION . . .
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3. CONVECTION

• The transfer of energy by the VERTICAL movement
  of particles in FLUIDS.
• Fluids are considered LIQUIDS or GASES.
• Important for weather patterns.
• http//channel.nationalgeographic.com/series/earth
  -the-biography/3130/Videos

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CONVECTION . . .
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4. ADVECTION

• The transfer of energy by the HORIZONTAL movement
  of particles in fluids.
• Important for weather patterns.
• Ex FOG

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These forms of heat transfer do not always act
alone!
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THE ALBEDO EFFECT

• Recall that ALBEDO is an objects ability to
  reflect LIGHT.
• LIGHT-coloured objects have a HIGH albedo.
• DARK-coloured objects have a LOW albedo.

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HOW MUCH OF THE SUNS ENERGY IS REFLECTED?

• Refer to Figure 4 on p. 506 of your text.
• If we count the Suns energy as starting with 100
  , then
• ____ is absorbed by land/oceans
• ____ is absorbed by clouds
• ____ is reflected by surface
• ____ is reflected by clouds

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HEAT SINK

• Any object or material that ABSORBS energy and
  becomes WARMER.
• A GOOD HEAT SINK is one that heats ups SLOWLY,
  absorbing a LARGE amount of heat before it heats
  up, such as WATER.
• A POOR HEAT SINK increases its temperature
  QUICKLY when exposed to even a SMALL amount of
  heat, but it LOSES heat just as quickly, such as
  what happens with rocks, soil, or sand.

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HEAT CAPACITY

• A measure of the amount of heat energy required
  to raise the temperature of 1 gram of a substance
  by 1oC.
• See Figure 5 on page 506 for a list of some heat
  capacities.
• WATER has a high heat capacity, meaning it has to
  absorb a lot of heat to increase in temperature.
• METALS has a low heat capacity, meaning it
  increases temperature with a relatively small
  addition of heat.

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HOMEWORK

• Q. 1, 2, 3, 4, 5, 6, 8 on p. 507.

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THE EARTHS SEASONS
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THE EARTHS SEASONS

• The earth rotates on its axis once a day in a
  COUNTERCLOCKWISE direction.
• The earth also orbits around the Sun elliptically
  and is tilted at an angle of 23.5o.
• The earths orbit around the Sun takes
  approximately 364.25 days.

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THE EARTHS SEASONS

• Changes in the intensity of the Suns rays, dues
  to daily and annual rotations, give us SEASONS.
• SOLSTICE
• Points when the poles are tilted at their MAXIMUM
  toward or away from sun.
• EQUINOX
• Suns rays strike Earths surface directly at
  EQUATOR.
• Day and night of roughly EQUAL length everywhere
  on earth.

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THE EARTHS SEASONS

• SUMMER SOLSTICE
• Northern hemisphere at MAXIMUM tilt TOWARD sun.
  (YAY SUMMER!!!)
• JUNE 21st is longest day of year.
• WINTER SOLSTICE
• Northern hemisphere at MAXIMUM tilt AWAY FROM
  sun. (BOO WINTER!!!)
• DEC 21st is shortest day of year.

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THE EARTHS SEASONS

• VERNAL EQUINOX (SPRING EQUINOX)
• Marks the first day of SPRING in the Northern
  Hemisphere (AROUND MARCH 21)
• AUTUMNAL EQUINOX
• Marks the first day of FALL in the Northern
  Hemisphere.(AROUND SEPTEMBER 21)

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THE ATMOSPHERE

• http//video.google.ca/videosearch?qlayersofthe
  atmospherehlenemb0aqf

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What is the Atmosphere?

• DEFINITION
• The blanket of air and water vapour that
  surrounds the Earth.
• If the earth were an ONION, the atmosphere would
  be like the ONION PEEL.
• It is about 500 km thick, containing 78 N , 21
  O , and some trace elements (ex CO2, H2O, Ar).

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LAYERS OF THE ATMOSPHERE

• Defined according to ALTITUDE, or elevation above
  sea level.
• TROPOSPHERE
• 8-16 km altitude, layer closest to earths
  surface
• This layer is the most dense, meaning it contains
  the most particles.
• Weather occurs in this layer.
• Temperature ranges from 20 to -50degrees Celsius.
• The tropopause is on the upper end of this layer.

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LAYERS OF THE ATMOSPHERE

• STRATOSPHERE
• 16-50 km altitude
• Very dry, temperature average is 10o degrees
  Celsius.
• This layer contains ozone, responsible for
  absorbing UV radiation from the Sun.
• Supersonic jets fly in this layer.
• MESOSPHERE
• 50-80 km altitude
• Temperature average is -75 degrees Celsius.

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LAYERS OF THE ATMOSPHERE

• THERMOSPHERE (IONOSPHERE)
• 80-500 km altitude
• Temperature average is 30o degrees Celsius.
• Molecules and ions have high energy because they
  are absorbing powerful waves from the SUN.
• On earth, we can see the Aurora Borealis in the
  Northern Hemisphere and the Aurora Australis in
  the Southern Hemisphere.

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LAYERS OF THE ATMOSPHERE

• EXOSPHERE
• Outer layer converging with SPACE.
• Thin layer, made up mostly of H and He particles.

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AURORAS

• The Sun ejects ionized particles into space that
  travel to the Earth. Earths magnetic field
  deflects these particles toward the poles,
  creating massive magnetic storms. They vibrate,
  and when they return to the original state, light
  is emitted.

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HOW DOES THE ATMOSPHERE SUPPORT LIFE?

1. Molecules such as O2, N2, H2O, CO2 needed to
   support life processes.
2. Ozone, O3,needed to absorb harmful UV rays.
3. Water cycle necessary to replenish water in
   atmosphere, land, and water bodies.
4. Protection from meteors.
5. Maintenance of ideal Temperature.
6. Move energy around the Earth.

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How did Life Begin?

• http//www.pbs.org/wgbh/nova/origins/

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ATMOSPHERIC PRESSURE

• Defined as the pressure that air particles exert
  as gravity pulls them toward the centre of the
  earth
• Air pressure is greatest at sea level where air
  is most dense (i.e., thick)
• Air pressure decreases with altitude.
• Thus, if you climb a mountain, the weight of the
  air above you is less, and the pressure is less.

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PRESSURE GRADIENT

• Another factor that affects air pressure is
  whether air is rising or falling.
• A pressure gradient is a measure of these changes
  in air pressure over set distance.
• Pressure gradients can be vertical or horizontal.

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HORIZONTAL PRESSURE GRADIENTS . . .

• Horizontal pressure gradients can be shown on a
  map by joining points of equal atmospheric
  pressure in concentric circles.
• They can be used to predict high and low pressure
  areas and direction and strength of winds.

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HOW DO WE MEASURE AIR PRESSURE?

• Air pressure is measured with an aneroid
  barometer, (aneroid meaning without water).
• Figure 5, p. 512.
• Air pressure is measured in kPa, or kilopascals.
  1 kPa 1000 Pa.
• If a barometer detects a
• low pressure system (less than 101.3 kPa), this
  is a sign of poor weather.
• High pressure system (greater than 101.3 kPa,
  this is a sign of good weather.

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HOW DO WE MEASURE AIR PRESSURE?
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WINDS

• Wind is the movement of air in the atmosphere.
• Some winds are local while others are prevailing.
• Local winds occur in a fairly small region.
• Prevailing winds are wind patterns that affect
  large regions around the world.

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PREVAILING WINDS

• In the early 1800s, SAILORS discovered that, in
  certain areas, the winds blow in the same
  direction all of the time.

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THE CORIOLIS EFFECT

• The change of DIRECTIONof a moving object in a
  constantly rotating system.
• The rotation of the EARTH deflects moving air AND
  water to the RIGHT of its initial direction in
  the Northern Hemisphere (opposite in the Southern
  Hemisphere).
• Note
• This direction of deflection is from the
  viewpoint of the starting position of WHAT IS
  BEING DEFLECTED (ex plane, wind, etc.).
• FIGURE 2 - pg. 517
• FIGURE 1 - pg. 525

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THE CORIOLIS EFFECT

• http//www.classzone.com/books/earth_science/terc/
  content/visualizations/es1904/es1904page01.cfm
• http//www.youtube.com/watch?vmcPs_OdQOYU

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THE CORIOLIS EFFECT
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THE CORIOLIS EFFECT
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HOMEWORK!!!

• 13.4 - Page 513, 7, 8, 9
• 13.6 READ section first, then answer Page 519,
  1, 2, 3, 4.

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Prevailing Winds in the Northern Hemisphere

• Prevailing Winds help distribute energy and
  moisture around the globe.
• TYPES IN NORTHERN HEMISPHERE
• Polar Easterlies
• Cold easterly winds blow from the poles to 60
  degrees.
• Mid-Latitude Westerlies
• Warm, moist winds blow from the west
• NEWFOUNDLAND is affected by these.
• North East Trade Winds
• Winds that blow toward the equator

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JET STREAMS

• Fast moving riversof air that race across the
  high altitude sky, sometimes at speeds as high as
  400 km/h.
• Jet streams occur about 7000 m up in the upper
  regions of the troposphere.
• They consist mostly of westerly winds, and are
  caused by strong differences in pressure and
  temperature.
• Air at the equator is thickerand moves from high
  to low pressure areas (i.e., N or S of the
  equator).
• Jet streams can be thousands of miles long,
  hundreds of miles wide, but only a mile or so
  deep.

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JET STREAMS

• Pilots can reduce flight time by hitching a ride
  on a jet stream.
• Long lines of clouds often indicate the presence
  of a jet stream.

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THE HYDROSPHERE

• Water covers 70 of the Earths surface, or 320
  million cubic miles.
• The hydrosphere is all the water that exists on
  the planet. It includes water in
• Oceans
• Rivers
• Lakes
• Aquifers
• Glaciers/ice
• Atmosphere

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WATER DISTRIBUTION

• 97.5 is salt water, 2.5 is fresh water.
• Most of our fresh water supply is trapped in
  polar ice caps (87.3).
• Canada is rich in fresh water resources, having
  10 of the total world supply.

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THE HYDROLOGICAL CYCLE

• Water is cycled through air, land, and water
  bodies.
• Important processes that occur in the water cycle
  include
• EVAPORATION liquid to gas
• CONDENSATION gas to liquid
• TRANSPIRATION evaporation from leaves
• SUBLIMATION solid to gas
• DEPOSITION gas to solid
• INFILTRATION seep into ground
• PRECIPITATION rain, snow, hail, sleet

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THE HYDROLOGICAL CYCLE
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MAJOR OCEAN CURRENTS

• Oceans have a HUGE effect on weather patterns.
  Here are just a few of the ways water is
  significant in this regard
• Oceans are heat sinks since most of the suns
  direct rays hit water.
• If water is warm, air above it is warm, meaning
  lots of moisture. If water is cold, air above it
  is cold.
• Warm water is constantly moving from the equator
  to the poles.
• Cold water is constantly moving from the poles to
  the equator.

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MAJOR OCEAN CURRENTS

• Which ones influence NEWFOUNDLAND weather?
  __________________________

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NEWFOUNDLAND AND LABRADOR
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WHAT CAUSES OCEAN CURRENTS?

• Convection currents
• Winds across oceans
• Earths rotation
• Shape of continents
• Heat capacity of Water
• Amount of salt in oceans

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FYI Just for FUN

• In 1992 a container ship in the middle of the
  Pacific Ocean lost 29 000 bath tub toys over the
  side.  Rubber duckies started washing ashore all
  over the west coast of North America. 
• In 1990 in a similar type accident 80,000 pairs
  of Nike shoes were swept off a Korean ship headed
  for the United states. Nike shoes started showing
  up from Hawaii to Oregon and as far north as
  Alaska. 
• These two accidents provided valuable information
  to oceanographers regarding ocean currents

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HOMEWORK!!!

• P. 524, 3,4,5
• P. 527, 1, 4, 6

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CLOUDS

• Clouds are a collection of water droplets that
  has become dense enough to be visible. Water
  evaporates and cools as it rises, and condenses
  into clouds.
• They are important indicators of weather
  patterns.
• Clouds can be grouped according to how they form,
  how they are shaped, whether or not they will
  lead to precipitation, and how high they are.

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3 TYPES OF CLOUD FORMATION

• 1. CONVECTION CLOUDS
• 2. OROGRAPHIC CLOUDS
• 3. FRONTAL CLOUDS

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1. CONVECTION CLOUDS

• Convection clouds form when warm air near heated
  surfaces such as the Earth gain energy from these
  sources.
• As this warm air rises in heat, it expands and
  carries water vapour into the atmosphere.
• The water vapour cools in the upper atmosphere,
  forming a convection cloud.
• These clouds are often puffy.

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1. CONVECTION CLOUDS
Something else puffy!
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2. OROGRAPHIC CLOUDS

• Orographic clouds result from warm, moist air
  ascending up a mountain, forming clouds on the
  upwind slope as the temperature decreases
• Thus, the near side of the mountain has
  precipitation, and the far side of the mountain
  is often dry.

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2. OROGRAPHIC CLOUDS

• http//www.pbs.org/wgbh/nova/kilimanjaro/weather.h
  tml

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3. FRONTAL CLOUDS

• Frontal clouds form when two air
  masses of different temperatures meet.
• Warm air masses generally are less dense and
  contain more moisture than cold air masses, thus
  rising over, or being pushed upward and over,
  cold air.
• The rising air cools and condenses forming a
  frontal cloud.
• Where the two air masses meet, this leading edge
  is called a FRONT.

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3. FRONTAL CLOUDS
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3. FRONTAL CLOUDS
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GROUPS OF CLOUDS

• BASED ON SHAPE
• CUMULUS clouds, from a term meaning pile or
  heap, referring to a TALL CLOUD
• STRATUS clouds, from stratum, or layer,
  referring to low-level layered clouds.
• BASED ON PRECIPITATION
• NIMBUS clouds, from a term meaning rain,
  referring to rain-bearing clouds
• BASED ON ALTITUDE
• LOW LEVEL NO PREFIX (0 2000 m)
• MEDIUM LEVEL ALTO (2000-5000 m)
• HIGH LEVEL CIRRUS (5000 m)

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CUMULUS CLOUD VS. STRATUS CLOUD
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CLOUDS
Cumulonimbus
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FOG

• Fog is a cloud that forms near the
• ground.
• Although there are many different types of fog,
  it basically forms such that water vapour, as it
  condenses, attaches
• itself to little particles such as
• dust specks.
• Some types of conditions that cause fog include
  heat rising from the Earths surface and cooling
  rapidly, warm air passing over snow, and warm
  ocean air meeting cold ocean air.

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FOG
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HOMEWORK

• P. 534 - 2, 4,
• P. 541 - 27
• Read and be familiar with Section 13.13, p. 536.

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WHAT WOULD HAPPEN IF

• http//www.pbs.org/wgbh/nova/elnino/anatomy/earths
  weather.html

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AND THATS ALL FOLKS!!! Fine Print Now study
for your exam!