高抒
从事海洋沉积动力学、海岸地貌学、海岸带陆海相互作用、海岸生态系统等领域的基础和应用基础研究。
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- 姓名:高抒
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学术头衔:
博士生导师
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学科领域:
海洋科学
- 研究兴趣:从事海洋沉积动力学、海岸地貌学、海岸带陆海相互作用、海岸生态系统等领域的基础和应用基础研究。
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21
【期刊论文】Tidal inlet stability in response to hydrodynamic and sediment dynamic conditions
高抒, Shu Gao, Michael Collins
Coslal Engineering 23 (1994) 61-80,-0001,():
-1年11月30日
Factors controlling tidal inlet stability are analysed and the general dynamic behaviour of an inlet in response tn hydrodynamic and sediment dynamic conditions are discussed, using an example from Christchurch Harbour (southem EngEand) A technique is developed for the estimation of current speeds within the entrance channel on the basis of the definition of the "apparent" basin area. The resuhs show that: (1) the Ω/M ratio as one of stability cnteria can be extended to include the influences of the charaeterislies of ddas and freshwater discarges: (2) for inlet systems eharaeterised by small flood and ebb tidal deltas and a pattern of by-passthg of sediments due to tidal currents, the equilibrium cross-sectional area can be dateminthed analytically; (3) the ratio of the difference belween flood and ebb sedimem discharges within the entrance to longshore sediment flux (i.e the parameter k defined in the present study) can be used as a stabi fity criterion; and (4) the evolution of an inlet system in response to an increase in longshore seth mere flux appears to be characterised by a de creasein AE and a constanl k value in early stages, but by a stow change in AE and a daereaease in kin laterstages (hence, these two stability erileria can he combined to describe [he inlet behavicurs in response to sediment movemenl. for different stages of evolution)
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高抒, SHU GAO AND MICHAEL COLLINS
EARTH SURFACE PROCESSES AND LANDFORMS, VOL. 19, 699-714 (1994),-0001,():
-1年11月30日
A simple approach to the estimate of long-term sediment discharge through an entrance to a tidal basin is descrihad. Using the method, cross-sectional mean current speeds are derived, on the basis of the definition of an 'apparent tidal basin area', from records of water levi data from a single tide gauge The obtained time-series of current speeds are then used to define 'local' current speeds, through the use of a sectional distribution function for the currents. Sediment transport formulae are then applied, using the obtained speed data and other relevant parameters contained within the formulae and frequency distribution functions with regard to wave and tidal current characteristics, to estimate sediment discharge through the entrance. Analytical procedures of the method are described in detail, in an example from Christchurch Harbour (southern England).
Tidal inlets Sediment discharge Chrischurch Harbour
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高抒
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-1年11月30日
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【期刊论文】Net Sand Transport Direction in a Tidal Inlet, using Foraminiferal Tests as Natural Tracers
高抒, Shu Gao and Michael Collins
Estuarine, Coastal and Shelf Science (1995) 40, 681-697,-0001,():
-1年11月30日
The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a 'critical level'. The critical level is etermined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern ngland. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance.
sediment transport, natural tracers, mathematical model, estuaries, foraminiferal tests, Christchurch Harbour
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【期刊论文】Hydrodynamics and sediment dynamics of The Wash bayment, eastern England
高抒, X. KE, *†, G. EVANS‡* and M.B. COLLINS*
,-0001,():
-1年11月30日
Water and sediment movement in The Wash embayment has been determined from an extensive set of data, consisting of tidal current readings and suspended sediment concentration measurements. Instantaneous and residual currents in the embayment show a distinct lateral inhomogeneity, Whereas vartically the water column is almost homogenous. The central deep water area (30-40m) of the embayment is dominated by a residual landward water movement, whilst on the margins, the residual movement is seaward. Sediment is supplied predominantly in suspension from the north, through the northern extremity of Boston Deep. Suspended sediment pathways are coincident with the spring tide water movements and the subtidal channels act the main conduits. Approximately 6.8×106 thonnes yr-1 of suspended sediments are supplied to the embayment from offshore areas. Bedload sediment supply is of lesser importance, ≈1.4×104 tonnes yr-1. Whereas suspended sediment movement appears to be the dominant mode of transport throughout the embayment, bedload transport is important in reforming the sea bed into a variety of bedforms which are particularly well developed on the margins of channels and shoals.
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高抒, S. Gao a, M.B. Collins a, J. Lanekneus b, G. De Moor b, V. Van Lancker b
Marine Geology 121 (1994) 171-185,-0001,():
-1年11月30日
Grain size trends in relation to net sediment transport pathways are examined, using some commonly-used grain size parameters. The results of the trend analysis (for 15 types of the trends) are compared with a known net sediment transport pathways established on the basis of the sandbank hydro- and sediment-dynamics (i.e. general water and sediment movement patterns and bedform asymmetry). It is shown that: (1) the results for grain size trends associated with "a worsening in sorting along the transport pathways" have little similarity to transport pathways: (2) the results for grain size trends associated with "an improvement in sorting along the transport pathways" have relatively high degree of similarity to the identified pathways; and (3) the residual pattern, derived on the basis of a combined grain size trend used elsewhere (Gao and Collins, 1992), appears to be most similar and suitable for defining transport
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高抒, Shu Gnu and Michael Collins
Sedimentary Geology, 80 (1992) 47-60,-0001,():
-1年11月30日
Gao, S. and Collins, M., 1992. Net sediment transport patterns inferred from grain-size trends, based upon definition of "transport vectors". Sediment. Geol, 80: 47-60 A new approach to the analysis of the grain-size trends, associated with net sediment transport directions in shallow marine enviroments, is developed here. Two specific trends, modified form McLaren and Bowles (1985) on the basis of a literature review, are used to define a grid of "trend vectors". Such vectors are filtered and transformed into "transport vectors". It is suggested that an ordered pattem of the transport vectors represents net trasnsport paths. The orderliness of the derived pattern is examined on the basis of a significance test, using the average length of the transport vectors as a criterion. Both the filtering operation and the significance test procedure are based upon the assumption that the trend vectors which are from Yangpu Harbour, southem China. The technique can be applied to inner continertal shelf and coastal environments. For such an analysis, the area under investigation should ber sampled at an interval large enough to reflect the real grain-size trends resulthng from net sediment transport, but small compared with the dimensions of the sedimentary environment. The time-scale of the results depends upon the sampling depth. Applicability of the technique is likely to be somewhat limited, where the environment is highly variable over short distances. Furthrmore, due to its statistical character, the analysis mqy fail to identify ner transport patterns.
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高抒, M.B. Collins, S.J. Shimwell, S. Gao*, H. Powell, C. Hewitson, J.A. Taylor
Marine Geology 123 (1995) 125-142,-0001,():
-1年11月30日
Geophysical surveys, current meter measurements and fluorescent sand tracer experiments were undertaken in the vicinity of the Broken Bank. The data are used to establish localised and regional patterns of water and sediment movement. The results obtained confirm mechanisms proposed previously for sandbank growth, with particular reference to the North Sea; these include the clockwise circulation of water and sand, with convergence at the crestline. Secondary helical water circulations do not appear to be a dominant process influencing sandbank maintenance. However, such circulation may still be important in the initial formation of linear sandbanks and/or at some stages in the bank development. On a regional basis, residual currents, bedform asymmetries and tracer dispersion indicate an offshore sediment transport component. This observation supports the hypothesis of other investigators, formed on the basis of geomorphological observations and numerical model predictions, concerning the movement of sand under extreme conditions. Moreover, these transport pathways may persist under low wave and tidally-dominated conditions, as opposed to being restricted to storm activity.
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高抒, SHU GAO
,-0001,():
-1年11月30日
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高抒, Shu Gao a, Qin-Chun Xie and Ying-Jun Feng
Estuarine, Coastal and Shelf Science (1990) 31, 397-409,-0001,():
-1年11月30日
During the winter of 1983, 25-h measurements of current speed, flow direction, water depth and suspended sediment concentration were carried out at six stations located in the inlet section of Xiangshan Bay, during spring and neap tides. An analysis of the data obtained shows that tidal exchange, in the form of either vertical residual circulation or bay-mouth water mixing, is responsible for the observed net landward movement of suspended sediment, though the ebb currents are stronger than the flood currents in the inlet. The analysis suggests also that the tidal exchange processes, in combination with the settling behaviour of the suspended sediments and the morphological features of the inlet section, lead to marked sorting of the fine-grained sediments with the clayey material predominating in the inner part of the bay and the silty material in the outer part.
suspended sediments, transport, estuaries, east China coast, circulation, mixing, filtering effects, sediment balance
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