| 释义 |
ionosphere|aɪˈɒnəsfɪə(r)|
[f. iono- + -sphere.]
A region of the outer atmosphere, beginning at a height of 50–80 km. (30–50 miles), which contains many ions and free electrons and is capable of reflecting radio waves; also, a corresponding region above other planets.
1926R. Watson-Watt Let. 8 Nov. in Nature (1969) 13 Dec. 1096/1 We have in quite recent years seen the universal adoption of the term ‘stratosphere’..and..the companion term ‘troposphere’... The term ‘ionosphere’, for the region in which the main characteristic is large scale ionisation with considerable mean free paths, appears appropriate as an addition to this series. 1929― in Q. Jrnl. R. Meteorol. Soc. LV. 278, I have suggested the name ionosphere to make the systematic group troposphere, stratosphere, ionosphere, but meanwhile the term ‘upper conducting layers’ seems to hold the field. 1932E. V. Appleton in Jrnl. Inst. Electr. Engin. LXXI. 642 (heading) Wireless studies of the ionosphere. [Note] This is a convenient term, suggested by Mr R. A. Watson Watt, connoting the ionized regions of the upper atmosphere. 1934Times 23 Feb. 20/2 Beyond lies the ionosphere, and of the layers in this we learn from the paths of radio-waves. 1947Sci. News IV. 55 Sir Edward Appleton, whom one might call the Master of the Ionosphere, distinguishes in it the following layers: the complex F-layer 250 kilometres (150 miles) above the earth (also called the Appleton layer), the E- or Heaviside layer at about 100 km., and further down the D layer which is little noticeable in normal times, but whose ionisation is considerably increased as long as a solar flare is visible. 1955Times 15 June 5/5 The ionosphere, a belt of gases ionized..by ultra violet rays from the sun and lying between 70km. and 300–400km. above the earth, makes medium and short wave radio propagation possible by reflecting signals back to earth. 1959Davies & Palmer Radio Stud. Universe iv. 66 This is difficult to explain if Jupiter is surrounded by an ionosphere similar to the Earth's. 1973Physics Bull. Feb. 93/3 Spacecraft observations of the ionospheres of Venus and Mars. |