What is a barometer?

Used for measuring atmospheric pressure, a barometer is scientific instrument that can help forecast shor-term weather changes.

There are several instruments used to measure air pressure that are used for analysis to assist monitoring surface troughs, high pressure systems and frontal boundaries.

Barometers and pressure altimeters are basically the same instrument, however, used for different purposes.

An altimeter is intended to be moved to various places matching the atmospheric pressure to the corresponding altitude, while barometer is kept in the same place measuring subtle pressure changes caused by the weather.  However, one exception to this is ships at sea.  Their elevation changes, which a barometer can be used to measure because their elevation does not change.  Weather systems and aircraft altimeters may need to be changed as they fly between destinations as atmospheric pressure changes.

The barometer was invented by Gasparo Berti, an Italian mathematician/astronomer, in 1643.  An unimaginable invention in those days.  By accident, Berti built a water barometer estimated to have happened between 1640 and 1643.

Rene’ Descartes, a french scientist, offered a description of the design of an experiment to determine atmospheric pressure as early as 1631, however, there is no evidence that Descartes built a barometer.

There are various types of barometers:

  • Water-based
  • Mercury
  • Vacuum pump oil
  • Aneroid
  • Baragraphs
  • MEMS

Applications of barometers

Barometers measuring barometeric pressure has been used since the 19th century.  When used in conjunction with wind semi-reliable forecast can be made.  Simultaneous readings from across weather station network helps build a map of air pressure, which was the first form of a weather map, created in the 19th century.  Localized high atmospheric pressure acts as a barrier to approaching weather, changing their course.  Atmospheric lift as a result of low-level wind  convergence into the surface brings clouds and possibly precipation.

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Additional resources: Wikipedia – Barometer