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METEOROLOGY (Gr. JerEwpa, and hb'yos,...
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See also:METEOROLOGY (Gr. JerEwpa, and hb'yos, i.e. the See also:science of things in the See also:air)
, the See also:modern study of all the phenomena of the See also:atmosphere of gases, vapours and dust that surrounds the See also:earth and extends to that unknown See also:outer See also:surface which marks the beginning of the so-called interstellar space
.
These phenomena may be studied either individually or collectively
.
The collective study has to do with See also:statistics and See also:general See also:average conditions, sometimes called normal values, and is generally known as Climatology (see See also:CLIMATE, where the whole subject of regional climatology is dealt with)
.
The study of the individual items may be either descriptive, explanatory, See also:physical or theoretical
.
Physical See also:meteorology is again sub-divided according as we consider either the changes that depend upon the motions of masses of See also:air or those that depend upon the motions of the gaseous molecules; the former belong to See also:hydrodynamics, and the latter are mostly comprised under See also:thermodynamics, See also:optics and See also:electricity
.
See also:History.—The See also:historical development of meteorology from the most See also:ancient times is well presented by the quotations from classic authors compiled by See also:Julius See also:Ludwig See also:Ideler (Meteorologia veterum graecorum et romanorum, See also:Berlin, 1832)
.
We owe to the Arabian philosophers some slight advance on the know-ledge of the Greeks and See also:Romans; especially as to the See also:optical phenomena of the atmosphere
.
The Meteorologia of See also:Aristotle (see See also:Zeller, Phil. der Griechen) accords entirely with the Philosophica of See also:
A
.
Bjerknes (1868), V
.
Bjerknes (1906), and to their many distinguished followers
.
The earliest systematic daily See also:record of See also:local See also:weather
phenomena that has survived is that kept by See also:
Such were See also: 21 appearing with vol . 3 of the Meteorologische Zeitschrifl of the German Meteorological Society in 1886, and since that date this See also:journal has been jointly maintained by the two See also:societies . The analogous See also:journals of the Royal Meteorological Society, London, 1850 to date, the Scottish Meteorological Society, 186o to date, the Meteorological Society of See also:France, 1838 to date, the See also:Italian Meteorological Society, and the See also:American Meteorological Journal, 1885—1895, have all played important parts in the history of meteorology . On the other See also:hand, the See also:Annals of the Central Meteorological See also:Office at Paris, the Archie of the Deutsche Seewarte at See also:Hamburg, the Annals and the Repertorium of the Central Physical See also:Observatory at St See also:Peters-See also:burg, the Annales of the Central Meteorological Office at See also:Rome, Bulletin of See also:International Simultaneous Met . Obs. and the Monthly Weather See also:Review of the Weather See also:Bureau at Washington, the Abhandlungen of the Royal Prussian Meteorological See also:Institute at Berlin, the Meteorological Papers of the Meteorological Office, London, and the transactions of numerous scientific societies, have represented the important See also:official contributions of the respective See also:national governments to technical meteorology . The recent international See also:union for aerial exploration by kites and balloons has given rise to two important publications, i.e. the Veroffentlichungen of the International . See also:Commission for Scientific Aerostatics (See also:Strassburg, 1905, et seq.), devoted to records of observations, and the Beitrdge zur Physik der freien Atmosphdre (Strassburg, 1904, et seq.), devoted to See also:research . The See also:necessity of studying the atmosphere as a unit and of securing See also:uniform accuracy in the observations has led to the formation of a permanent International Meteorological See also:Committee (of which in 1909 the secretary was Professor Dr G . Hellmann of Berlin, and the See also:president Dr W . N . See also:Shaw of London) . Under its directions conferences and general congresses have been held, beginning with that of 1872 at Leipzig .
Its Inter-national Tables, See also:Atlas of Clouds, Codex of Instructions, and Forms for Climatological Publications illustrate the activity and usefulness of this committee
.
Modern meteorology has been See also:developed along two lines of study, based respectively on maps of monthly and See also:annual averages and on daily weather maps
.
The latter study seems to have been begun by H
.
W
.
Brandes in Leipzig, who first, about 1820, compiled maps for 1783 from the data collected in the Ephemerides mannheimensis, and subsequently published maps of the See also:European storms of 182o and 1821
.
Simultaneously with Brandes we find William C
.
Redfield in New Yorkcompiling a See also:chart of the See also:hurricane of 1821, which was published in 1831, and was the first of many memoirs by him on hurricanes that completely established their rotary and progressive See also:motion
.
Soon after this Piddington and Sir William See also:Reid began their great works on the storms of the Orient
.
About 1825 See also: J . J . Le Vervier, at Paris, an opportunity to propose the proper action, and his proposals were immediately adopted by the secretary of See also:war, See also:Marshal Valliant . On the 17th of See also:February 1855 the See also:emperor ordered the director-general of government telegraph lines to co-operate completely with Le Verrier in the organization of a bureau of telegraphic meteorology . The international daily bulletin of the Paris Observatory began to be printed in regular See also:form on the 1st of See also:January 1858, and the daily map of isobars was added to the See also:text in the autumn of 1863 . The further development of this bulletin, the inclusion of See also:British and ocean reports in 186r, the addition of special storm warnings it1 1863, the publication of the Atlas See also:des mauvements generaux covering the See also:Atlantic in 1865, the study of local thunderstorms by Hippolyte See also:Marie-See also:Davy, Sonrel, Fron, Peslin, in France, and the work of See also:Fitzroy, See also:Buys-See also:Ballot, See also:Buchan, Glaisher and See also:Thomson in Great See also:Britain, parallel the analogous works of the American students of meteorology and form the beginnings of our modern dynamic meteorology . The details of the historical development of this subject are well given by See also:Hugo See also:Hildebrand-Hildebrandsson and See also:Leon Teisserenc de See also:Bort in their See also:joint work, See also:Les Bases de la meteorologie dynamique (Paris, 1898-1907) . The technical material has been collected by Hann in his Lehrbuch . Many of the See also:original memoirs have been reproduced by Brillouin in his Memoires originaux (Paris, 1900), and in See also:Cleveland See also:Abbe's See also:Mechanics of the Earth's Atmosphere (vol. i., 1891; vol. ii., 1909) . The publication of daily weather charts and forecasts is now carried on by all civilized nations . The See also:list of government bureaux and their publications is given in See also:Bartholomew's Atlas (vol. iii., London, 1899) . Special establishments for the exploration of the upper atmospheric conditions are maintained at Paris, Berlin, See also:Copenhagen, St See also:Petersburg, Washington and Strassburg . The general problems of climatology (1900) are best presented in the Handbook of Dr Julius Hann (2nd ed., Stuttgart, 1897) . The general See also:distribution of temperature, winds and pressure over the whole globe was first given by Buchan in charts published by the Royal Society of See also:Edinburgh in 1868, and again greatly revised and improved in the See also:volume of the Challenger reports devoted to meteoro+ logy . The most complete atlas of meteorology is Buchan and Herbertson's vol. iii. of Bartholomew's Atlas (London, 1899) . Extensive works of a more special character have been published by the London Meteorological Office, and the Deutsche Seewarte for the Atlantic, Pacific and See also:Indian Oceans . Daily charts of atmospheric conditions of the whole northern hemisphere were published by the U.S . Weather Bureau from 1875 to 1883 inclusive, with monthly charts; the latter were continued through .1889 . The physical problems of meteorology were discussed in Ferrel's Recent Advances in Meteorology (Washington, 1885) . Mathematical papers on this subject will be found in the author's collection known as The Mechanics of the Earth's Atmosphere; the memoirs by Helmholtz and Von Bezold contained in this. collection have been made, the basis of a most important work by Brillouin (Paris, 1898), entitled Vents contigus et nuages . A general ,See also:summary of our knowledge of the mechanics and physics of the atmosphere is contained in the See also:Report on the International See also:Cloud Work, by F . H . See also:Bigelow (Washing-ton, 1900) . The extensive Lehrbuch (Leipzig, 1901; 2nd ed., 1906) by Dr Julius Hann is an authoritative work . The optical phenomena of the atmosphere are well treated by E . Mascart in his Traite d'optique (Paris, 1891-1898), and by J . M . Penter, Meteorologische Optik (1904-1907) . Of See also:minor treatises especially adapted to collegiate courses of study we may mention those by Sprung (Berlin, 1885) ; W . Ferrel (New See also:York, 1890) ; Angot (Paris, 1898) ; W . M.See also:Davis, (See also:Boston, 1893) ; See also:Waldo (New York, 1898) ; See also:Van Bebber (Stuttgart, 189o) ; See also:Moore (London, 1893) ; T . See also:Russell (New York), 1895 . The brilliant volume by Svante See also:Arrhenius, Kosmische Physik (Leipzig, 1900) contains a See also:section by Sandstrom on meteorology, in which the new hydrodynamic methods of Bjerknes are developed . I.—FUNDAMENTAL PHYSICAL DATA There can be no proper study of meteorology without a See also:consideration of the various physical properties of the atmospheric gases and vapours, each of which plays an See also:independent See also:part, and yet also reacts upon its neighbours . Atmospheric air is a mixture of nitrogen, oxygen, aqueous vapour, carbonic acid gas (See also:carbon dioxide), See also:ammonia, argon, neon, See also:helium, with slight traces of See also:free See also:hydrogen and hydro-carbons . The proportions in which these gases are See also:present are quite See also:constant, except that the percentage of aqueous vapour is subject to large See also:variations . In an atmosphere that is saturated at the temperature of 90° F., as may occur in such a climate as that of See also:Calcutta, the water may be 240A of the whole weight of any given volume of air . When this aqueous vapour is entirely abstracted, the remaining dry gas is found to have a very uniform constitution in all regions and at all altitudes where examination has been carried out . In this so-called dry atmosphere the relative weights are about as follows: Oxygen, 23.16; nitrogen and argon, 76.77; carbonic acid, o•o4; ammonia and all other gases, less than o•oi in the See also:lower See also:half of the atmosphere but probably in larger percentages at great altitudes . Of still greater rarity are the highly volatile gases, argon (q.v.), neon, krypton and helium (q.v.) . Outer Limit.—These exceedingly volatile components of the atmosphere cannot apparently be held down to the earth by the attraction of See also:gravitation, but are continually diffusing through the atmosphere outwards into interstellar space, and possibly also from that region back into the atmosphere . There are doubtless other volatile gases filling interstellar space and occasionally entering into the atmosphere of the various See also:planets as well as of the See also:sun itself ; possibly the hydrogen and hydro-carbons that See also:escape from the earth into the lower atmosphere ascend to regions inaccessible to See also:man and slowly diffuse into the outer space . The laws of See also:diffusion show that for each gas there is an See also:altitude at which as many molecules diffuse inwards as outwards in a unit of See also:time . This See also:condition defines the outer limit of each particular gaseous atmosphere, so that we must not imagine the atmosphere of the earth to have any general boundary . The only intimation we have as to the presence of gases far above the surface of the globe come from the phenomena of the See also:Aurora, the See also:refraction of See also:light, the See also:morning and evening twilight, and especially from the See also:shooting stars which suddenly become luminous when they pass into what we See also:call our atmosphere . (See C . C . See also:Trowbridge, ' On Luminous See also:Meteor Trains " and " On Movements of the Atmosphere at Very Great Heights," Monthly Weather Review, See also:Sept .
1907.)
Such observations are supposed to show that there is an appreciable quantity of gas at the height of, See also:loo m., where it may have a See also:density of a millionth part of that which prevails at the earth's surface
.
Such See also:matter is not a gas in the ordinary use of that See also:term, but is a collection of particles moving independently of each other under those influences that emanate from sun and earth, which we call radiant See also:energy
.
According to Stormer this radiant energy is that of electrons from the sun, and their movements in the magnetic See also:
Geol
.
Jour., published memoirs in which they argued that a variation of several per cent. in the proportion of carbonic acid gas is quite consistent with the existence of See also:animal and See also:vegetable See also:life and may explain the variations of climate during See also:geological periods
.
But the specific absorption of this gas for See also:solar radiations is too small (C
.
G
.
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