| 释义 |
▪ I. downˈwelling, vbl. n.
[f. down adv. + welling vbl. n.1, after upwelling vbl. n.]
Flow of fluid downwards in a larger body of fluid, esp. the sea or the atmosphere; sinking; also, a downward current.
1963G. L. Pickard Descriptive Physical Oceanogr. ix. 189 In the exchange of water within the upper layer, downwelling in regions of convergence is also important. 1973Nature 23 Mar. 252/1 Convective motions of subcrustal material would lead to an accumulation of lighter crustal material above regions of downwelling. 1979Ibid. 14 June 614/1 The downwelling in the polar region [of the Venusian atmosphere] must be explained in terms of a circulation mechanism which produces a poleward meridional flow. 1984A. C. & A. Duxbury Introd. World's Oceans vi. 185 Downwelling is a mechanism that transports oxygen-rich surface water to depth, where it is needed for the deep-living animals. Ibid. xii. 389 Downwellings are regions of low plant growth.
▪ II. ˈdownwelling, ppl. a.
[f. down adv. + welling ppl. a., after upwelling ppl. a.]
That downwells; that pours downwards.
1955Jrnl. Optical Soc. Amer. XLV. 904/1 Monochromatic measurements in situ have been made of radiance distribution,..reflectance, upwelling, and downwelling irradiance. 1967Oceanogr. & Marine Biol. V. 61 Wyrtki (1960) considered the greater part of the downwelling water is made up of Subtropical Water. 1982Sci. Amer. Feb. 116 (caption) The guppy can..detect dark objects against the downwelling light, but the lower retina is not suitable for discriminating colors. |