| 释义 |
jet stream
[f. jet n.3 + stream n.]
a. A fast-moving, relatively narrow stream of fluid that is present as a current in an atmosphere or ocean; spec. in Meteorol., a strong wind confined to a narrow region of the atmosphere, esp. one in the upper troposphere at middle latitudes that blows in an approximately horizontal direction, predominantly from west to east.
1947Bull. Amer. Meteorol. Soc. XXVIII. 255 During periods of reasonably straight west wind circulation over the North American continent, there exists normally, at levels between 5 km and 15 km above sea level, a fairly narrow zone of extremely strong west wind circulation (jet stream), reaching its maximum intensity and sharpness at the tropopause level. 1950Time 29 May 70/2 Six miles up, where the air is thin and cold, a fearful wind zigzags round the earth at 200 m.p.h. Meteorologists call it the ‘jet stream’. 1957G. E. Hutchinson Treat. Limnol. I. iv. 225 The jet-stream mechanisms believed to maintain circulation in the region of the westerlies. 1963tr. E. R. Reiter's Jet-Stream Meteorology iv. 271 (heading) Jet streams in the oceans. Ibid., The current does not spread out..but it remains concentrated in a narrow band of high velocities—the oceanic jet stream. 1971New Scientist 8 Apr. 90/2 In the tropopause..there is a meandering hemispheric band of high speed westerly winds, called the jet streams.
b. A jet of fluid (jet n.3 4), esp. one ejected by a jet engine.
1955Sci. News Let. 5 Mar. 160/3 Graphite lubricant is propelled in a jet-stream reaching many often inaccessible trouble spots. 1955Ibid. 26 Mar. 200/1 These air whirlpools are not caused by either the propeller backwash or jet stream, but by the action of the plane's wings. 1959S. N. Samburoff tr. Feodosiev & Siniarev's Introd. Rocket Technol. vii. 232 The presence of the jet stream..introduces certain specific peculiarities into rocket aerodynamics. 1962H. E. Newell Express to Stars iii. 29 It takes a force to expel material into a jet stream..and by Newton's law of reaction there must be a reaction force. |