| 释义 |
ˈunderfit, a. Physical Geogr.
[f. under-1 10 c, after misfit.]
Pertaining to or designating a stream which, if its average flow in the past was at present-day levels, would be expected to have eroded a smaller valley than it has done. Cf. overfit a.
1913W. M. Davis in Ann. Assoc. Amer. Geographers III. 3 Underfit Rivers.—The chief object of this paper is to call attention to an explanation recently suggested for the peculiar relation that is frequently observed between the small-curved meanders of a river and the larger-curved meanders of its valley, a relation that has been called ‘underfit’. 1939A. K. Lobeck Geomorphology vi. 199 The beheaded stream, having lost much of its volume, acquires mature characteristics. It develops small meanders not suited to the size of the valley. It becomes a misfit, or an underfit, stream. 1964,1968[see misfit n. 2]. 1970R. J. Small Study of Landforms ii. 46 In post-glacial times, the old channels have been choked with alluvium, and the meandering valleys are now followed by ‘under⁓fit’ streams, possessing insufficient power to effect further erosion.
Hence underˈfitness, the property or state of being underfit.
1913Ann. Assoc. Amer. Geographers III. 24 The lower Seine in Normandy shows a slight underfitness. 1964Prof. Papers U.S. Geol. Survey No. 452-a. 29/2 The underfitness of streams in incised meandering valleys can no longer be denied. |