thermosphere
(ˈθɜːməʊsfɪə(r))
[f. thermo- + sphere n.]
1. † a. (See quot. 1924.) Obs. rare—1. b. The part of the atmosphere between the mesopause and the height at which it ceases to have the properties of a continuous medium, characterized throughout by an increase of temperature with height.
| 1924 S. N. Sen in Q. Jrnl. R. Meteorol. Soc. L. 29 Up to an approximate height of 8 km. above the ground the air density is chiefly controlled by the temperature. The name ‘thermosphere’ is proposed to denote this layer of the atmosphere. 1950 S. Chapman in Jrnl. Geophysical Res. LV. 396, I propose the name..thermosphere for the layer of upward increasing temperature above that level [i.e. of the mesosphere]. 1967 R. W. Fairbridge Encycl. Atmospheric Sci. 731/2 At the top of the thermosphere, the temperature approaches a constant value of ∼ 1500°K. 1981 Sci. Amer. July 46/3 On the earth the thermosphere is present day and night; the large-scale rotation of the atmosphere with the planet carries the heated day-side upper atmosphere to the night side of the planet. On the night side of Venus, however, the thermosphere disappears. |
2. The warmer, upper part of the oceans.
| 1956 Nature 16 June 1106 (in figure) Thermosphere. 1957 [see psychrosphere s.v. psychro-]. |
Hence thermosˈpheric a.
| 1971 Nature 29 Jan. 333/2 Calculations suggest that the thermospheric winds may produce some net rotation [of the atmosphere] at low latitudes. 1979 Ibid. 8 Feb. 458/2 Rocket measurements of mesospheric and thermospheric nitric oxide concentrations revealed strong enhancements during auroral particle precipitation events. |