meteorology, branch of science that deals with the atmosphere atmosphere [Gr.,=sphere of air], the mixture of gases surrounding a celestial body with sufficient gravity to maintain it. Although some details about the atmospheres of other planets and satellites are known, only the earth's atmosphere has been well studied, the
..... Click the link for more information. of a planet, particularly that of the earth, the most important application of which is the analysis and prediction of weather weather, state of the atmosphere at a given time and place with regard to temperature, air pressure (see barometer ), wind, humidity, cloudiness, and precipitation.
..... Click the link for more information. . Individual studies within meteorology include aeronomy, the study of the physics of the upper atmosphere; aerology, the study of free air not adjacent to the earth's surface; applied meteorology, the application of weather data for specific practical problems; dynamic meteorology, the study of atmospheric motions (which also includes the meteorology of other planets and satellites in the solar system); and physical meteorology, which focuses on the physical properties of the atmosphere.

Development of Meteorology

Aristotle's Meteorologica (c.340 B.C.) is the oldest comprehensive treatise on meteorological subjects. Although most of the discussion is inaccurate in the light of modern understanding, Aristotle's work was respected as the authority in meteorology for some 2,000 years. In addition to further commentary on the Meteorologica, this period also saw attempts to forecast the weather according to astrological events, using techniques introduced by Ptolemy.

As speculation gave way to experimentation following the scientific revolution, advances in the physical sciences made contributions to meteorology, most notably through the invention of instruments for measuring atmospheric conditions, e.g., Leonardo da Vinci's wind vane (1500), Galileo's thermometer thermometer, instrument for measuring temperature . Galileo and Sanctorius devised thermometers consisting essentially of a bulb with a tubular projection, the open end of which was immersed in a liquid.
..... Click the link for more information. (c.1593), and Torricelli's mercury barometer barometer (bərŏm`ətər), instrument for measuring atmospheric pressure.
..... Click the link for more information. (1643). Further developments included Halley's account of the trade winds trade winds, movement of air toward the equator, from the NE in the Northern Hemisphere and from the SE in the Southern Hemisphere. The trade winds originate on the equatorial sides of the horse latitudes , which are two belts of high air pressure, one lying between
..... Click the link for more information. and monsoons monsoon (mŏnsn) [Arab.
..... Click the link for more information. (1686) and Ferrel's theory of the general circulation of the atmosphere (1856). The invention of the telegraph made possible the rapid collection of nearly simultaneous weather observations for large continental and marine regions, thus providing a view of the large-scale pressure and circulation patterns that determine the weather.

Modern Meteorological Science and Technology

In 1917 the Norwegian physicist Vilhelm Bjerknes Jakob Aall Bonnevie Bjerknes, 1897–1975, who became a U.S. citizen in 1946. Jakob Bjerknes served as professor of meteorology at the Univ. of Bergen (1931–40) and at the Univ. of California (from 1940).
..... Click the link for more information. introduced his theory describing the formation of wave cyclones cyclone, atmospheric pressure distribution in which there is a low central pressure relative to the surrounding pressure. The resulting pressure gradient, combined with the Coriolis effect , causes air to circulate about the core of lowest pressure in a
..... Click the link for more information. on the polar front polar front, zone of transition between polar and tropical air masses . Its average position during the winter is at about 30° lat. and during the summer at about 60° lat.
..... Click the link for more information. and laid the foundation for modern methods of weather forecasting. In 1922, L. F. Richardson perceived the basis for the mathematical prediction of the atmospheric circulation, and in 1938 C. G. Rossby made additional mathematical contributions. Application of this treatment by Richardson and Rossby awaited the introduction of high-speed electronic computers, which were first used for weather forecasting in the late 1940s by J. G. Charney and John Von Neumann. By 1955 computer forecasts were being made operationally and computer forecasting models have been improved steadily since then.

Since 1959 meteorological satellites satellite, artificial, object constructed by humans and placed in orbit around the earth or other celestial body (see also space probe ). The satellite is lifted from the earth's surface by a rocket and, once placed in orbit, maintains its motion without further
..... Click the link for more information. have provided an overview of the atmosphere's cloud patterns, serving among other things as an early warning and detection system for hurricanes hurricane, tropical cyclone in which winds attain speeds greater than 74 mi (119 km) per hr. Wind speeds reach over 190 mi (289 km) per hr in some hurricanes.
..... Click the link for more information. , typhoons, and tropical cyclones. Infrared sensors mounted on meteorological satellites now provide observations of the vertical temperature structure of the atmosphere, and research efforts continue the development of computer forecasting models capable of utilizing these and other satellite data to improve current weather-predicting skills. Meteorological studies have been aided by the use of large computers for atmospheric modeling. Information gathered by weather balloons and earth-orbiting satellites have been used in computer models to predict long-term and short-term meteorological events such as changes in ozone ozone (ō`zōn), an allotropic form of the chemical element oxygen (see allotropy ).
..... Click the link for more information. levels and daily movements of storms, respectively.

The National Oceanic and Atmospheric Administration (NOAA) has the major governmental responsibility in the United States for monitoring and forecasting the weather and conducting meteorological research. The Air Weather Service and the Fleet Numerical Weather Control have similar responsibilities within the U.S. Air Force and U.S. Navy, respectively; space applications to meteorology are researched by the National Aeronautics and Space Administration (NASA) as well as by the National Environmental Satellite Service, which is under the auspices of NOAA. In addition to a host of universities conducting meteorological research, there is the National Center for Atmospheric Research, which is operated by an affiliation of universities and sponsored by the U.S. National Science Foundation. The World Weather Watch, organized by the World Meteorological Organization, collects and disseminates information on a global basis. A number of private companies also engage in operational and research meteorological activities.

Bibliography

See C. D. Ahrens, Meteorology Today (1988); J. M. Moran, Meteorology (1991).

meteorology

Scientific study of atmospheric phenomena, particularly of the troposphere and lower stratosphere. Meteorology entails the systematic study of weather and its causes, and provides the basis for weather forecasting. See also climatology.