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meteorology,branch of science that deals with the atmosphereatmosphere
[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 science of
..... 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 weatherweather,
state of the atmosphere at a given time and place with regard to temperature, air pressure (see barometer), wind, humidity, cloudiness, and precipitation. The term weather
..... 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 thermometerthermometer,
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 barometerbarometer
, instrument for measuring atmospheric pressure. It was invented in 1643 by the Italian scientist Evangelista Torricelli, who used a column of water in a tube 34 ft (10.4 m) long.
..... Click the link for more information. (1643). Further developments included Halley's account of the trade windstrade 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 25° and
..... Click the link for more information. and monsoonsmonsoon
[Arab., mausium=season], wind that changes direction with change of season, notably in India and SE Asia. To a lesser degree, monsoonal winds also develop in portions of all other continents except Antarctica.
..... 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 BjerknesBjerknes, Vilhelm Frimann Koren
, 1862–1951, Norwegian physicist and pioneer in modern meteorology. He worked on applying hydrodynamic and thermodynamic theories to atmospheric and hydrospheric conditions in order to predict future weather conditions.
..... Click the link for more information. introduced his theory describing the formation of wave cyclonescyclone,
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 counterclockwise direction
..... Click the link for more information. on the polar frontpolar 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 satellitessatellite, 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 rocket propulsion.
..... 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 hurricaneshurricane,
tropical cyclone in which winds attain speeds greater than 74 mi (119 km) per hr. Wind speeds gust over 200 mi (320 km) per hr in some hurricanes. The term is often restricted to those storms occurring over the N Atlantic Ocean; the identical phenomenon occurring over
..... 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 balloonsweather balloon,
balloon used in the measurement and evaluation of mostly upper atmospheric conditions (see atmosphere). Information may be gathered during the vertical ascent of the balloon through the atmosphere or during its motions once it has reached a predetermined maximum
..... Click the link for more information. and earth-orbiting satellites have been used in computer models to predict long-term and short-term meteorological events such as changes in ozoneozone
, an allotropic form of the chemical element oxygen (see allotropy). Pure ozone is an unstable, faintly bluish gas with a characteristic fresh, penetrating odor. The gas has a density of 2.144 grams per liter at STP.
..... 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 Force Weather Agency and the Fleet Numerical Meteorology and Oceanography Center 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, Data, and Information 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.
See C. D. Ahrens, Meteorology Today (1988); J. M. Moran, Meteorology (1991).
the science of the atmosphere and the processes occurring in it. The main branch of meteorology is atmospheric physics, which studies physical phenomena and processes. Chemical processes are the concern of atmospheric chemistry, a new and rapidly developing branch of meteorology. Dynamic meteorology is the study of atmospheric processes through the theoretical methods of hydroaeromechanics; one of the important problems of this branch is developing methods of numerical weather prediction. Among the other branches of meteorology are synoptic meteorology, the science of weather and methods of forecasting, and climatology, which has become an independent discipline. These disciplines use both physical and geographic research methods, but physical methods dominate in recent work. Biometeorology is concerned with the influence of atmospheric factors on biological processes; it also includes agricultural meteorology and human biometeorology.
Atmospheric physics deals with the surface air layer and processes in the lowest layer of the atmosphere; aerology, which is concerned with processes in the free atmosphere, where the influence of the earth is less significant; and upper air layers at altitudes of hundreds and thousands of km, where the density of atmospheric gases is very low. Aeronomy deals with the physics and chemistry of the upper air layers. Atmospheric physics also includes actinometry, which studies solar radiation in the atmosphere and the transformations of solar radiation; atmospheric optics, the science of optical phenomena in the atmosphere; atmospheric electricity; and atmospheric acoustics.
The first investigations in meteorology go back to ancient times (Aristotle). Meteorology developed more rapidly in the first half of the 17th century, when the Italian scientists Galileo and E. Torricelli developed the first meteorological instruments, the barometer and thermometer.
The first steps in studying the principles of atmospheric processes were taken in the 17th and 18th centuries. At this time outstanding meteorological research was carried out by M. V. Lomonosov and B. Franklin, both of whom devoted special attention to atmospheric electricity. During the same period instruments for measuring wind speed, amount of precipitation, humidity, and other meteorological elements were invented and perfected. This made it possible to begin systematic observations of the atmosphere using instruments. First, observations were made at individual points, but from the late 18th century on, networks of meteorological stations were employed. The international network of meteorological stations that make surface weather observations over most of the world was established in the mid-19th century.
Observations of the atmosphere at different altitudes were first made in the mountains and, soon after the invention of the aerostat in the late 18th century, in the free atmosphere. Since the late 19th century pilot balloons and sounding balloons with self-registering instruments have been used extensively to observe meteorological elements at varying altitudes. In 1930 the Soviet scientist P. A. Molchanov invented the radiosonde, an instrument that transmits data on the free atmosphere by radio. Radiosonde observation subsequently became the principal method of investigating the atmosphere at aerological stations. In the mid-20th century a world actinometric network was established; its stations conduct observations of solar radiation and its transformations at the earth’s surface. Moreover, methods have been developed for observing ozone content in the atmosphere, elements of atmospheric electricity, the chemical composition of atmospheric air, and the like. Parallel with the expansion of meteorological observations the science of climatology has developed, based on statistical generalization of material from observations. A. I. Voeikov, who studied such atmospheric phenomena as general atmospheric circulation, the hydrologic cycle, and snow cover, made a large contribution to the establishment of climatology as a discipline.
In the 19th century empirical investigations of atmospheric circulation were used to substantiate methods of weather forecasting. The work of W. Ferrel in the United States and H. Helmholtz in Germany marked the beginning of investigations into the dynamics of atmospheric movements; this research was continued in the early 20th century by the Norwegian scientist V. Bjerknes and his students. Further progress in dynamic meteorology was marked by the creation of a method for numerical hydrodynamic weather forecasting, which was worked out by the Soviet scientist I. A. KibeF, and the rapid development of this method that followed.
In the mid-20th century the methods of dynamic meteorology were used extensively in studying general atmospheric circulation. By using these methods the American meteorologists J. Smagorinsky and S. Manabe constructed world charts of air temperature, precipitation, and other meteorological elements. Similar research is underway in many countries; these investigations are closely connected with the International Global Atmospheric Research Program. Modern meteorology devotes considerable attention to studying physical processes in the air layer near the ground. This line of investigation was begun in the 1920’s and 1930’s by the German R. Geiger and other scientists in order to study the microclimate, and it led to the creation of a new branch of meteorology, the physics of the boundary layer of air. Investigations of changes in the climate, in particular, studies of the increasingly noticeable effect of human activity on climate, is important in meteorology.
In Russia meteorology had reached a high level in the 19th century. The Main Physical (today Geophysical) Observatory, which was set up in St. Petersburg in 1849, was one of the first scientific meteorological establishments in the world. In Russia, G. I. Vil’d, who directed the observatory for many years during the second half of the 19th century, created a model system of meteorological observations and a weather service. He was one of the founders of the International Meteorological Organization (1871) and chairman of the international commission for the First International Polar Year (1882–83). During the Soviet period a number of new meteorological establishments have been founded, including the Hydrometeorological Research Center of the USSR (formerly the Central Institute of Forecasts), the Central Aerological Observatory, and the Institute of Atmospheric Physics of the Academy of Sciences of the USSR.
A. A. Fridman was the founder of the Soviet school of dynamic meteorology. His work and the later work of N. E. Kochin, P. la. Kochina, E. N. Blinova, G. I. Marchuk, A. M. Obukhov, A. S. Monin, and M. I. ludin was devoted to the principles of atmospheric movements on various scales and led to the first models of a theory of climate and the development of a theory of atmospheric turbulence. The work of K. la. Kondrat’ev dealt with the principles of radiation processes in the atmosphere.
The climate of the Soviet Union has been studied in detail, and the atmospheric processes that determine it have been investigated in the works of A. A. Kaminskii, E. S. Rubinshtein, B. P. Alisov, O. A. Drozdov, and other Soviet climatologists. In research carried out at the Main Geophysical Observatory, the heat balance of the globe was studied, and atlases with charts of the constituent parts of the balance were prepared. Work in synoptic meteorology (V. A. Bugaev, S. P. Khromov) has significantly increased the accuracy of weather forecasting. The research of Soviet agrometeorologists (G. T. Selianinov, F. F. Davitai) has provided the basis for the optimal placement of crops in the Soviet Union.
Work in the Soviet Union on actively influencing atmospheric processes has led to important results. Experiments on controlling clouds and precipitation, which were begun by V. N. Obolenskii, developed extensively in the postwar years. Research carried out under the direction of E. K. Fedorov resulted in the establishment of the first system that makes it possible to lessen the damage done by hail over a large area.
A typical feature of modern meteorology is use of the latest advances of physics and technology. Thus, the state of the atmosphere is observed by meteorological satellites that make it possible to receive worldwide information on many meteorological elements. Radar is used for ground observation of clouds and precipitation. Automation of meteorological observations and of data processing is steadily increasing. Computers are widely used in research on theoretical meteorology, and their use has been enormously important for improving numerical weather forecasting. The use of quantitative physical methods of investigation is expanding in such areas as climatology, agro-meteorology, and human biometeorology—areas in which these methods were hardly used before.
Meteorology is closely bound up with oceanography and land hydrology. These three sciences study different elements of the same processes of heat exchange and moisture exchange in the earth’s geographic shell. The connection between meteorology and geology and geochemistry is based on the common goals of these sciences in studying the evolution of the atmosphere and changes in the earth’s climates in the geological past. Modern meteorology makes extensive use of the methods of theoretical mechanics, as well as the data and methods of many other physical, chemical, and technical disciplines.
One of the main goals of meteorology is to forecast weather for different periods of time. Short-range forecasts are especially essential for aviation; long-term forecasts are extremely important for agriculture. Data on climatic conditions are vital for the national economy because meteorological factors have a significant effect on many aspects of economic activity. Active influences on atmospheric processes—for example, controlling clouds and precipitation, protecting plants against frosts, and the like—are rapidly growing in practical importance.
Scientific and practical work in meteorology is directed by the Hydrometeorological Service of the USSR, which was established in 1929.
The World Meteorological Organization and other international meteorological organizations bring together the work of different countries. The International Association of Meteorology and Atmospheric Physics, which is part of the International Union of Geodesy and Geophysics, also holds international conferences on various problems of meteorology. The most important conferences on meteorology in the USSR are the All-Union Meteorological Congresses; the last (fifth) congress was held in June 1971 in Leningrad. Work being done in meteorology is published in meteorological journals.
REFERENCESKhrgian, A. Kh. Ocherki razvitiia meteorologii, 2nd ed., vol. 1. Leningrad, 1959.
Meteorologiia i gidrologiia za 50 let Sovetskoi vlasti. Edited by E. K. Fedorov. Leningrad, 1967.
Khromov, S. P. Meteorologiia i klimatologiia dlia geograficheskikh fakuVtetov. Leningrad, 1964.
Tverskoi, P. N. Kurs meteorologii. Leningrad, 1962.
Matveev, L. T. Osnovy obshchei meteorologii: Fizika atmosfery. Leningrad, 1965.
Fedorov, E. K. Chasovye pogody. [Leningrad] 1970.
M. I. BUDYKO