Atmosphere section 2

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Atmosphere section 2

• Water and Wind

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• June 11th Lecture 2 Lab Day
• June 13th Lecture 3 Add. Project
• June 15th Review Folder Due!
• June19th Test!
• June 21st Last Day!

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Agenda

• Notes Section 2 Water and Wind
• Lab Day

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Review Layers of the Atmosphere
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Notes Section 2

• Wind and Water

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The Water Cycle

• Water cycle the continuous movement of water
  from the ocean to the atmosphere to the land and
  back to the ocean

Know the 4 main terms of the water cycle!
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• Plants contribute large volumes of atmospheric
  water vapor to the air
• through the process of
• A) transpiration.
• B) evaporation.
• C) condensation.
• D) respiration.

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The Water Cycle, continued

• Air contains varying quantities of water vapor.
• Humidity the amount of water vapor in the air.
• Relative humidity is the actual amount of vapor
  in the air compared to the maximum amount the air
  could hold at that temperature.
• Air that has a relative humidity of 100 is said
  to be saturated

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Water cycle, continued

• Evaporation of water increases as temperature
  increases.
• Warm air can hold more water vapor than cold air
  can.

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The Water Cycle, continued

• Dew point is the temperature at which air or a
  gas begins to condense to a liquid (Dew point
  D\Ch22\80254.html)
• When humidity is high, there are more molecules
  of water in the air and it is easier to form
  liquid.
• The higher the humidity, the higher the dew
  point.

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• Condensation and the formation of cumulus clouds
  begins as the rising air reaches its
• dew point.
• minimum altitude.
• maximum altitude.
• evaporation point.

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The Water Cycle, continued

• Clouds form as warm, moist air rises.
• Clouds form when warm air rises and water vapor
  condenses into tiny droplets of liquid as it
  cools.
• usually occurs in the troposphere.
• Rain and snow formation D\Ch22\80440.html

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• What condition is likely to form clouds?
• warm air moving over warm air
• Cold air moving over cold air
• warm air moving over cold air
• No movement of air

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• Cloud names describe their shape and altitude.
• Cirrus clouds are thin, wispy, and occur at high
  altitudes
• Stratus clouds are sheet-like and layered
• Cumulus clouds are white and fluffy with somewhat
  flat bottoms

Cumulonimbus clouds are towering rain clouds that
often produce thunderstorms. Nimbostratus clouds
are large, gray clouds that often produce steady
precipitation.
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High Pressure Vs. Low Pressure

• 1) In a high-pressure system,
• air molecules are far apart and pressing on
  Earths surface.
• air molecules are far apart and rising away from
  Earths surface
• air molecules are close together and pressing on
  Earths surface
• air molecules are close together and rising away
  from Earths surface.

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Air Pressure

• Barometric pressure the pressure due to the
  weight of the atmosphere also called air
  pressure or atmospheric pressure
• At sea level, the barometric pressure of air at 0
  C is around 760 mm of mercury(1atm).
• Instruments used to measure air pressure are
  called barometers. (Example of barometer
  D\Ch22\80266.html)
• Changes in barometric pressure often accompany
  changes in the weather.
• Falling pressure may indicate that a large air
  mass is leaving the area.
• Rising air pressure may mean that an air mass is
  moving in.

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Wind

• Differences in pressure create winds.
• (pressure differences at equator and poles
  D\Ch22\80243.html)
• When air pressure varies from one place to
  another, a pressure gradient exists.
• The air in a pressure gradient moves from areas
  of high pressure to areas of low pressure.
• This movement of air from a high-pressure area to
  a low-pressure area is called wind.

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Air becomes wind as it flows from

• A) low pressure to low pressure.
• B) low pressure to high pressure.
• C) high pressure to high pressure.
• D) high pressure to low pressure.

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Wind, continued

• Earths rotation affects the direction of winds.
• Coriolis effect as air begins flowing from high
  to low pressure, the Earth rotates under it,
  making the wind follow a curved path.
• In the Northern Hemisphere, the wind turns to the
  right of its direction of motion. In the Southern
  Hemisphere, it turns to the left.
• Points at different latitudes on Earths surface
  move at different speeds.
• Earth goes through a full rotation in 24 hours.
• Points on the equator travel the Earths full
  circumference in 24 hours.
• Points closer to the poles do not travel as far.

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Coriolis Effect
Example of Coriolis Effect. D\Ch22\80215.html Me
rry go round example http//ww2010.atmos.uiuc.edu
/(Gh)/guides/mtr/fw/gifs/coriolis.mov
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Wind, continued

• Global wind patterns form circulation cells.
• Because temperatures closer to the equator tend
  to be warmer, air traveling toward the equator
  tends to rise.
• Warm rising air tends to move toward the poles.
• As air moves closer to the poles it cools and
  sinks.
• Cells Three loops of rising warm air and
  sinking cold are can be found in each hemisphere

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Wind Belts
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• The direction in which the wind moves is
  influenced by
• the pressure gradient.
• Earths rotation.
• Both (a) and (b)
• None of the above

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• Due to the Coriolis effect, winds in the Northern
  Hemisphere
• curve to the north.
• curve to the south.
• curve clockwise.
• curve counterclockwise.

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Wind and Ocean Currents

• Most currents in the upper kilometer of the ocean
  are driven by the wind. The surface currents
  resemble the surface winds
• Wind energy is converted to water movements
  called "currents" by friction between the wind
  and the water surface.
• Once these surface currents are set in motion
  they are influenced by three other factors
  Coriolis effect, presence of coasts, and
  horizontal pressure gradients.

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Ocean Currents The arrows in the image represent
the currents directions. The length of the arrows
represents the currents speed. The colors in the
image represent the topography of the ocean
surface. The reds and yellows are the " hills "
and the blues and purples are the " valleys. "
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Sea Breeze (Cool ocean air)

• occurs when the temperature of the land is
  normally higher than the temperature of the
  water. (Spring, Summer)
• Warm air rises over the land and allows the
  cooler ocean air to move towards land.

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Land Breeze

• On clear, calm evenings, cooler land temps/warmer
  water temps cause a cool wind blowing from land
  towards the water.
• Land breezes are strongest along the immediate
  coastline but weaken considerably further inland.

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Example of an upwelling
Trade winds (surface winds) pull the surface
water away from shore. Upwelling brings in cold,
nutrient rich water- helps support ecosystem by
providing food for fish
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The easterly trade winds are driven by a surface
pressure pattern of higher pressure in the
eastern Pacific and lower pressure in the west.
When this pressure gradient weakens, so do the
trade winds. The weakened trade winds allow
warmer water from the western Pacific to surge
eastward, so the sea level flattens out.
El Nino 1
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This leads to a build up of warm surface water
and a sinking of the thermocline in the eastern
Pacific. The deeper thermocline limits the
amount of nutrient-rich deep water tapped by
upwelling processes. These nutrients are vital
for sustaining the large fish populations
normally found in the region and any reduction in
the supply of nutrients means a reduction in the
fish population.
El Nino 2
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Convective clouds and heavy rains are fueled by
increased buoyancy of the lower atmosphere
resulting from heating by the warmer waters
below. As the warmer water shifts eastward, so do
the clouds and thunderstorms associated with it,
resulting in dry conditions in Indonesia and
Australia while more flood like conditions exist
in Peru and Ecuador.
El Nino 3
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El Nino 4
El Niño causes all sorts of unusual weather,
sometimes bringing rain to coastal deserts of
South America which never see rain during non-El
Niño years. The flooding results in swarming
mosquitoes and the spread of disease.
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El Niño

• Occurs every three to seven years
• El Niños can last from six to eighteen months.
• Examples of El Nino weather
• 1) severe coastal storms, heavy rainfall,
  flooding and mud slides in California on the west
  coast of the United States.
• 2) droughts in Mexico and Central America, which
  led to forest fires that burned for long periods
  of time and sent heavy smoke north to the United
  States.
• 3) droughts in Australia which caused a water
  shortage.
• 4) unusually mild winters on the east coast of
  the United States.
• 5) droughts in the mid-west of the United
  States.
• 6) economic disaster to the Peruvian fisheries.

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La Niña

• In contrast to El Niño, La Niña refers to an
  anomaly of unusually cold sea surface
  temperatures found in the eastern tropical
  Pacific. La Niña occurs roughly half as often as
  El Niño.

La Nina
Normal
El Nino
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La Nina Impacts

• In the U.S., winter temperatures are warmer than
  normal in the Southeast, and cooler than normal
  in the Northwest.

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• Normally, tradewinds blow warm surface water
  westward toward low pressure in the Western
  Pacific. The warm surface water is replaced with
  cold, nutrient rich water that is upwelled from
  below the surface. When the tradewinds weaken,
  surface pressure patterns break down and the flow
  of warm water is reversed. This phenomenon is
  called
• El Nino
• A hurricane
• La Nina
• monsoon

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• When tradewinds in the Pacific are unusually
  strong and the equatorial oceanic surface
  temperatures are colder than normal than drought
  can occur in the Southern United States and
  excess rainfall can occur in the northwest. This
  condition is called
• El Nino
• A hurricane
• La Nina
• A monsoon

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Lab Choices

• Section 1 The Greenhouse Effect
• - set-up in the sun
• - Review Practice Quiz
• Section 2 Convection Currents Lab
• - heated water/cold water movements
• - Review Practice Quiz
• Section 3 Angle of Sunlight Lab
• - Angle of Sunlight/Air Temperature Surfaces
  (2 Parts)
• - Practice Quiz