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Add To Table of Contents:Weather TrackingPg. 100Weather InstrumentsPg. 101Weather InstrumentsPg. 101A. Lower Atmosphere:1. Thermometer - temperature

What does a barometer measure?2. Barometer measures atmospheric pressure.

How a Barometer works

What does a anemometer measure?3. Anemometer measures wind speed.

What does a hygrometer measure?4. Hygrometer measures humidity = amount of water vapor in the air.

hygrometer uses two basic mercury thermometers, one with a wet bulb one with a dry bulb. Evaporation from the water on the wet bulb causes its temperature reading to drop, causing it to show a lower temperature than the dry bulb. Relative humidity is calculated by comparing the readings using a calculation table that compares the ambient temperature (the temperature given by the dry bulb) to the difference in temperatures between the two thermometers.

What does a weather vane measure?5. weather vane measures wind direction

Strong Wind Gust 5/12/14

B. Upper atmosphere:Radiosonde a helium weather balloon carries weather instruments high into the atmosphere.

2. Radar = radio detection and ranging -reflects radio waves to determine velocity and location of objects.3. Satellites use visible, infrared and cloud vapor to show where storms are.