meteorology

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Atmospheric chart showing Rotch's findings at Blue Hill: humidity, temperature, and horizontal wind speed, at day and at night.

Meteorology, the study of atmospheric conditions and weather, both advanced the progress of aeronautics and benefited from it. This relationship was exemplified by the International Commission for Scientific Aeronautics, whose members developed the ballon-sonde as an atmospheric assay.

Key elements

Abbott Lawrence Rotch in Conquest of the Air (1909) opens with a discussion of the importance of temperature, humidity, clouds, and (especially) wind for aeronautics. Rotch summarizes some key facts about the lower troposphere, including:

  • Greater wind speed (though fewer gusts) at higher elevations, with exceptions;
  • Changes in wind direction with elevation (which enable some navigation in LTA craft without propulsion);
  • The existence of upward and downward wind currents;
  • Diminishing temperature and humidity with elevation (with inverse variations during day and night; see figure)

History

In the eighteenth century meteolorgy was fostered by the Royal Society, which communicated with observers worldwide. Kite experiments (by Alexander Wilson, Benjamin Franklin, et al) began midcentury, and soon after after balloons came on the scene these were used as well (by Jacques Charles, John Jeffries, et al).[1]

John Wise was an early advocate of balloon meteorology, commenting in 1870:

In the science of meteorology there is no instrumentality competent to do so much good, and which has as yet received so little attention as the balloon. The phenomena of the atmosphere, in their relations to climate and sanitary effects—to agriculture, to physiology—to our mental forces and temperaments, are more fertile in scientific developments than an observer from the earth would suppose. Meteorological investigations are as occult, tame, and spiritless, without the aid of an air-ship, as would by hydrographical investigations without the watership. [...] It is a marvel that so fruitful a subject, and one so easily to be explored, is so much neglected.[2]

Wise himself had made many observations on clouds, atmosphere, optics, electricity, etc.

Official meteorological offices (U.S. Weather Bureau, Meteorological Office) arose in the industrialized countries and these were networked by scientists traveling to international conferences. The International Meteorological Committee formed in 1873 and spawned the International Commission for Scientific Aeronautics in 1896.

Kites enabled big advances; as reported by Nature (perhaps rereporting a lecture by Rotch to the Royal Meteorology Society) in 1897:

The United States Weather Bureau has been conducting experiments with kites flown at distances of from one to two miles above the earth, and now it is claimed that it is possible to forecast the weather for a period of sixteen hours longer than at present, and more accurately. It is said that the fact has been established, that the shifting of the wind occurs at the height of a mile above the earth's surface form twelve to sixteen hours before the same change of direction occurs on the surface. Researches by means of high-flown kites and aeroplanes have now been prosecuted so far as to warrant the expectation that, within six months, the United States Weather Bureau will be able to construct a telegraphic synchronous chart, based on conditions of the atmosphere, one mile above the earth. This chart will cover the region between the Rockies and the Alleghanies at the outset.[3]

Rotch's work at Blue Hill Observatory popularized the use of kites for meteorology, and by 1900 Teisserenc de Bort and Richard Aßmann had brought his methods to Europe.[4]

(Meanwhile the ballon-sonde method, originating in Europe, diffused to America, its first use there occurring at the St. Louis World's Fair.)

Links

References

  1. Walker, 2012, p. 9−11.
  2. "The Balloon as an Aid to Meteorological Research: a paper read by Prof. John Wise before the Franklin Institute"; Scientific American, Vol. XXIII, No. 22, 26 November 1870.
  3. Nature, June 24, 1897, p. 182; quoted in the Aeronautical Journal, Vol. 1., No. 3, July 1897, p. 17.
  4. Hildebrandt, 1908, Airships Past and Present, pp. 255–256.
Enclosing categories sciences
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Keywords instrument, thermometer
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