[雙語翻譯]--港航外文翻譯--破碎孤立波作用下沿岸泥沙輸移（原文）

1、Cross-shore sediment transport under breaking solitary wavesNobuhisa Kobayashi and Andrew R. LawrenceCenter for Applied Coastal Research, University of Delaware, Newark, Delaware, USAReceived 5 August 2003; revised 16 De

2、cember 2003; accepted 30 January 2004; published 27 March 2004.[1] Laboratory experiments were performed to examine the cross-shore sediment transport processes under breaking solitary waves on a fine sand beach. The ini

3、tial beach slope of 1/12 was exposed to a positive solitary wave eight times. The beach was rebuilt and exposed to a negative solitary wave eight times. The wave motion and sediment transport were not affected much by th

4、e beach profile change from the initial profile. The positive solitary wave plunged violently near the shoreline and suspended a considerable volume of sand. The plunging wave with no seaward flow impeding its run-up cau

5、sed large run-up on the foreshore. The strong downrush following the large run-up resulted in erosion on the foreshore and deposition seaward of wave run-down. On the other hand, the negative solitary wave collapsed agai

6、nst the seaward flow induced by the free surface slope of the negative wave and caused less sediment suspension. The wave run-up against the seaward flow was much smaller. The weak downrush following the small run-up res

7、ulted in deposition on the foreshore and erosion near the wave collapsing point. These limited laboratory experiments indicate the importance of the initial wave profile for swash sediment dynamics and the capacity of a

8、single wave in causing noticeable beach profile changes. INDEX TERMS: 4558 Oceanography: Physical: Sediment transport; 4564 Oceanography: Physical: Tsunamis and storm surges; 4546 Oceanography: Physical: Nearshore proces

9、ses; 4568 Oceanography: Physical: Turbulence, diffusion, and mixing processes; KEYWORDS: sediment transport, solitary wave, breaking waveCitation: Kobayashi, N., and A. R. Lawrence (2004), Cross-shore sediment transport

10、under breaking solitary waves, J. Geophys. Res., 109, C03047, doi:10.1029/2003JC002084.1. Introduction[2] Sediment transport processes on beaches under tsunamis have been studied very little in comparison to a large numb

11、er of studies performed for sediment transport processes under wind waves and currents as reviewed concisely by Kobayashi and Johnson [2001]. The sheets of marine-derived sediments deposited along the west coast of North

12、 America have been used to identify historic tsunamis [e.g., Clague et al., 1999; Witter et al., 2001], but tsunamis also caused beach erosion [Synolakis et al., 1995]. Presently, it is not possible to quantitatively rel

13、ate the sediment deposition or beach erosion to the characteristics of tsunamis. Moreover, no data are available to develop a sediment transport model for tsunamis, partly because it is practically impossible to install

14、the necessary instrument immediately before the arrival of a tsunami. [3] Wave run-up and flooding caused by tsunamis have been studied using incident solitary waves or N-shaped waves [e.g., Tadepalli and Synolakis, 1994

15、]. The semi- analytical solution of Carrier et al. [2003] for non-breaking tsunami run-up and run-down on plane beaches has indi- cated that the maximum fluid velocity occurs at the shore- line during the downrush phase

16、for predominantly positive initial waves and during the uprush phase for predominantlynegative initial waves, which may be caused by an offshore submarine landslide. On the basis of the computed veloc- ities, they have p

17、redicted the seaward and landward move- ments of sediments under positive and negative initial waves, respectively. It is not clear whether their prediction holds for breaking waves because bore-generated turbu- lence ha

18、s been shown to be important for sediment suspen- sion and transport in the swash zone on a beach [Puleo et al., 2000]. [4] In this study, laboratory experiments were conducted to examine the cross-shore sediment transpo

19、rt and beach profile changes under positive and negative solitary waves that broke on a fine sand beach. Section 2 describes the laboratory experiments. Sections 3 and 4 present the posi- tive and negative solitary wave

20、test results, respectively, to show the importance of the initial wave profile in deter- mining the breaker type, sediment suspension, uprush, downrush and net sediment transport. Section 5 summarizes the findings of thi

21、s paper. It is noted that the report of Lawrence and Kobayashi [2003] tabulates and plots all the data discussed in this paper.2. Experiments[5] Experiments were conducted in a wave tank that was 30 m long, 2.4 m wide, a

22、nd 1.5 m high as shown in Figure 1. The experimental setup was the same as the previous irregular wave experiments by Giovannozzi and KobayashiJOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, C03047, doi:10.1029/2003JC002084,

23、2004Copyright 2004 by the American Geophysical Union. 0148-0227/04/2003JC002084$09.00C03047 1 of 13location of the solitary wave breaking in the region where the velocities could be measured reliably without the effect o

24、f bubbles produced by plunging breakers for tests P1–P8. The reliability of the velocity measurement was assessed by comparing the velocity time series measured by the two velocimeters. [11] A fiber optic sediment monito

25、r (FOBS-7) with two sensors was used to measure the sand concentration at the elevation of 6 cm above the local bottom atthe two alongshore symmetric locations 4.5 cm from the flume centerline at the cross-shore location

26、 of the velocity measurement. The FOBS-7 is a laboratory version of the optic sensors used for concentration measurements on natural beaches [Downing et al., 1981]. The reliability of the concentration measurement was ev

27、aluated by comparing the concentration time series measured by the two sensors where high concentration events occurred simultaneously in both time series. [12] The experimental procedure for tests P1–P8 is summarized in

28、 the following. The initial beach profile was measured and the eight wave gauges, two velocimeters, and two concentration sensors were installed at the specific locations. A positive solitary wave was generated and all t

29、he measurements were collected synchronously at the sam- pling rate of 20 Hz for the duration of wave action on the beach. The beach profile was measured to quantify the vertical profile change of the order of 1 cm. The

30、elevations of the velocimeters and concentration sensors were adjusted to measure the velocities and concentrations at the elevation of 6 cm above the deformed bottom. The subsequent solitary wave was generated on the de

31、formed beach to assess the effects of the evolving beach profile on the solitary wave transformation and resulting beach profilechange. The beach was exposed to the eight positive solitary waves at the end of test P8. Af

32、ter tests P1–P8, the beach was reconstructed and the initial beach profile was mea- sured before tests N1–N8. The experimental procedure for tests N1–N8 is the same as for tests P1–P8 except that the incident solitary wa

33、ve was negative.3. Positive Solitary Wave Tests[13] Figure 3 shows the temporal variations of the free surface elevation h1 above SWL measured by wave gauge 1 for tests P1–P8 where time t = 0 at the start of theFigure 3.

34、 Measured (solid line) and theoretical (dotted line) positive solitary wave profiles at wave gauge 1.Figure 4. Measured beach profiles and wave gauge locations for tests P1–P8.C03047 KOBAYASHI AND LAWRENCE: SOLITARY WAVE