Weather Instrumentation

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Weather Instrumentation

• 7th Grade Science
• Mr. Bombick

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Weather Instruments

• Thermometer
• Barometer
• Hygrometer
• Rain Gauge
• Anemometer
• Doppler Radar
• Satellites

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Thermometer

• Relies on the measurement of temperature by the
  property of matter to expand with thermal energy
  or emit thermal radiation
• Common thermometers using mercury or alcohol
  measure increasing temperature by expansion of
  liquid by thermal energy
• Thermistor is an electronic component that
  changes its resistance with changing thermal
  energy
• Thermocouple is a metal component that expands
  and contracts with changing thermal energy (the
  movement of the metal component is measured to
  give the temperature)
• Infrared thermometer examines the amount of
  infrared energy being emitted from the object
• Galileo thermometer uses enclosed balls with
  solutions of different densities that float at
  different temperatures

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Barometer

• Barometers measure the atmospheric pressure
• Barometers come in two major types-mercury and
  aneroid
• Mercury barometers examine the rise of mercury in
  a tube of an open system with the air
• Aneroid barometers measure the expansion of a
  metal spring in an enclosed container that
  expands or contracts because of changes in air
  pressure

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Hygrometer

• A hygrometer measures the relative humidity of
  the air
• Types of hygrometers include metal/pulp coil,
  hair tension, resistive electronic, capacitive
  electronic, thermal conductivity, and chilled
  mirror dew point electronic hygrometers
• Metal/pulp coil hygrometers are common and rely
  on the changes of a salt-impregnated paper strip
  to move a metal coil with changing water levels
  in the air (these are also inaccurate and hard to
  keep calibrated)
• Hair tension hygrometers rely on the changes in
  the length of hair with changing relative
  humidity
• The electronic hygrometers are usually more
  accurate (the chilled mirror dew point hygrometer
  is the most accurate) and stay calibrated for
  longer periods of time

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Rain Gauge

• Measures the amount of precipitation over a
  period of time
• Standard rain gauge relies on collection of
  precipitation over time using a standard size
  graduated cylinder (0.2 mm increments)
• Gravimetric rain gauges measure the weight of
  precipitation and calculate the volume based on
  weight (the advantage of this rain gauge is that
  it is precipitation type independent)
• Tipping bucket rain gauge is an instrument that
  contains a bucket that is tipped after a a known
  quantity of precipitation fills the bucket (the
  amount of tips is recorded and total
  precipitation is calculated)
• Optical rain gauge uses a laser diode and photo
  transistor detector that can count drops of
  waters and calculate total amount of precipitation

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Anemometer

• An anemometer measure the wind speed and is often
  coupled with a device to determine wind direction
• Types of anemometers include cup, windmill,
  hot-wire, laser Doppler, and ping pong ball
• Cup anemometers use cups that catch the wind and
  rotate around a pole
• Wind mill anemometers look like an airplanes
  propeller that moves with the wind
• Hot-wire anemometers measure the winds cooling
  effect on a wire that has been heated to a
  precise temperature
• Laser Doppler anemometers use the Doppler effect
  to measure wind speed
• Ping Pong ball anemometer uses a ping pong ball
  attached to a string that will move with the wind
  (the wind speed is calculated from the angle the
  string moves away from a 90o angle perpendicular
  to a horizontal line)

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Doppler Radar

• A type of radar that uses microwaves to reflect
  off atmospheric objects (clouds, dust, and
  precipitation)
• The Doppler effect examines the change in
  wavelength as an object moves toward or away from
  an object
• Using the Doppler effect the speed of atmospheric
  objects can be calculated
• Doppler radar is very important in determining
  the nature of storm fronts and predictions of
  possible tornadic activity

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Weather Satellites

• Weather satellites are instrumental in measuring
  weather phenomena
• Weather satellites can record visual information
  such as clouds, particulate concentrations,
  hurricanes, and typhoons
• Weather satellites can also measure temperatures
  using infrared technology

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The End