共查询到20条相似文献，搜索用时 250 毫秒
1.
Spatial backshore processes were investigated through field observations of topography and median sand grain size at a sandy beach facing the Pacific Ocean in Japan. A comparison of the backshore profile and cross‐shore distribution of the median sand grain size in 1999 and 2004 revealed an unusual sedimentary process in which sand was coarsened in a depositional area in the 5‐year period, although sediment is generally coarsened in erosional areas. In support of these observations, monthly spatial field analyses carried out in 2004 demonstrated a remarkable backshore coarsening process triggered by sedimentation in the seaward part of the backshore during a storm event. In order to elucidate mechanisms involved in the backshore coarsening process, thresholds of movable sand grain size under wave and wind actions (a uniform parameter for both these cases) in the onshore and offshore directions were estimated using wave, tide, and wind data. The cross‐shore distributions of the estimated thresholds provided reasonable values and demonstrated a coarsening mechanism involving the intermediate zone around the shoreline under alternating wave and wind actions as a result of which coarse sand was transported toward the seaward part of the backshore by large waves during storms and then toward the landward part by strong onshore winds. The 5‐year backshore coarsening is most certainly explained by repetition of short‐term coarsening mechanisms caused by wave‐induced sand transport occurring from the nearshore to the intermediate zone. Copyright © 2010 John Wiley & Sons, Ltd 相似文献
2.
Clara Lemos France Floc’h Marissa Yates Nicolas Le Dantec Vincent Marieu Klervi Hamon Véronique Cuq Serge Suanez Christophe Delacourt 《Ocean Dynamics》2018,68(9):1207-1220
Eleven-year long time series of monthly beach profile surveys and hourly incident wave conditions are analyzed for a macrotidal Low Tide Terrace beach. The lower intertidal zone of the beach has a pluriannual cycle, whereas the upper beach profile has a predominantly seasonal cycle. An equilibrium model is applied to study the variation of the contour elevation positions in the intertidal zone as a function of the wave energy, wave power, and water level. When forcing the model with wave energy, the predictive ability of the equilibrium model is around 60% in the upper intertidal zone but decreases to 40% in the lower intertidal zone. Using wave power increases the predictive ability up to 70% in both the upper and lower intertidal zones. However, changes around the inflection point are not well predicted. The equilibrium model is then extended to take into account the effects of the tide level. The initial results do not show an increase in the predictive capacity of the model, but do allow the model free parameters to represent more accurately the values expected in a macrotidal environment. This allows comparing the empirical model calibration in different tidal environment. The interpretation of the model free parameter variation across the intertidal zone highlights the behavior of the different zones along the intertidal beach profile. This contributes to a global interpretation of the four model parameters for beaches with different tidal ranges, and therefore to a global model applicable at a wide variety sites. 相似文献
3.
J. Tinker T. O’Hare G. Masselink T. Butt P. Russell 《Continental Shelf Research》2009,29(16):1948-1960
A new field-based parameterisation (‘shape function’) describing the distribution of cross-shore suspended sediment transport across a beach profile is presented. Time-averaged and depth-integrated suspended sediment fluxes were measured over 39 tides at Sennen Cove, Cornwall, UK, for a range of wave conditions (offshore significant wave heights 0.1–2.5 m). The suspended sediment flux data were heuristically separated into four transport components: (1) mean flux in the surf/shoaling zone; (2) oscillatory flux in the surf/shoaling zone; (3) onshore flux in the swash/inner surf zone and (4) offshore flux in the swash/inner surf zone. Each of these transport components was related to the local water depth (h) normalised by the breakpoint depth (hb) and the four resulting suspended transport shape functions were combined to form a total suspended load shape function. Each shape function component is scaled independently by the wave energy level through hb. The total suspended load shape function predicts onshore sediment transport under low-energy conditions, with peaks at the breakpoint and in the swash zone, in agreement with the field observations. Under high-energy conditions the total suspended load shape function predicts onshore transport in the shoaling zone, offshore transport in the surf zone and onshore transport in the inner swash zone. 相似文献
4.
Julian D. Orford 《地球表面变化过程与地形》1977,2(4):381-400
One of the major problems of shingle beach dynamics is the method by which coarse gravel is transferred from beach face to storm beach, the latter often lying several metres above high spring tidal levels. The mechanism which is usually proposed, cites the action of plunging breakers as being central to this problem of sediment transfer. However, the nature of net residual fluid force of plunging breakers is deemed unsatisfactory for any substantial upbeach (onshore) sediment transport during storm conditions on gravel beaches. A mechanism is proposed by which high still water levels due to high astronomical tides, onshore storm force winds and allied wave surge, promote shoaling characteristics and beach profile changes which are conducive to spilling breaker development at tidal extremities. It is the net onshore fluid force vector of the spilling breaker overtopping the beach crest which may be the cause of extreme sedimentation events on the storm beach. An example of such sediment transfer is given for a known storm beach sedimentation event at Llanrhystyd gravel beach, West Wales, during February 1974. Process variables were monitored on several days allowing the use of an inshore breaker steepness criterion, to indicate positions in the tidal regime where plunging breakers give way to spilling forms. This example serves to suggest that more attention should be given to the nature and characteristics of shoaling waves, especially in respect of breaker type, when examining problems of shingle beach dynamics and sedimentation. 相似文献
5.
Karl F. Nordstrom 《地球表面变化过程与地形》1989,14(8):691-701
Analysis of grain size statistics of upper foreshore sediments on sand beaches at two tidal inlets in New Jersey, U.S.A. reveals that sediments are coarser at beaches flanking the inlets than updrift, although sediments become finer downdrift at the broad, regional scale. The local reversal of the regional trend in size grading is attributed to: (1) the offshore diversion of the finer sands along the surf zone on the ebb tidal delta, and (2) the removal of the finer sands from the inlet flank beach caused by low wave energy conditions at low stages of the tide and by deflation. Sediments thus become coarser at inlet beaches as a result of alterations in the interaction of waves with the beach and as a result of aeolian processes, not solely as a result of increased tidal current velocities as previously reported. The distance along the New Jersey barrier islands over which inlet processes are likely to affect changes in sediment size updrift averages less than 1100 m, but the impacts of inlets on the sedimentary record can be extended greater distances as a result of inlet migration. 相似文献
6.
The present contribution considers the dynamics of beaches occupied by outcropping/buried beachrocks, i.e. hard coastal formations consisting of beach material lithified by in situ precipitated carbonate cements. The dynamics of a Greek microtidal beach with beachrocks (Vatera, Lesbos) are examined through the collection and analysis of morphological and sedimentary field data, a 2-D nearshore hydrodynamic model and a specially constructed 1-D morphodynamic model. The results showed that the beachrock-occupied part of the beach is characterised by distinctive morphodynamics as: (i) its beachface is associated with large slopes; (ii) there is a good spatial correlation between the sub-aerial and shallow submerged mean beach profile and the buried/outcropping upper beachrock surface; and (iii) the seaward margins of the submerged beachrock outcrops are always associated with a ‘scour step’ i.e. a submerged cliff. The results also showed that beachrock outcrops can bias cross-shore sediment exchanges by impeding onshore transport due to the presence of the scour step. In this sense, beachrock outcrops may be considered as offshore transport ‘conduits’ for the beach sediments. A conceptual model of beach sediment transport, based on the field data and the hydrodynamic modelling is proposed. According to this model, fresh beach material from adjacent terrestrial sources is transported alongshore, towards the central part of the embayment, where a littoral transport convergence zone occurs under most wave conditions. There, the laterally supplied sediments are lost offshore. 相似文献
7.
D. W. T. Jackson J. H. M. Beyers K. Lynch J. A. G. Cooper A. C. W. Baas I. Delgado‐Fernandez I 《地球表面变化过程与地形》2011,36(8):1113-1124
The behaviour of offshore‐directed winds over coastal dune and beach morphology was examined using a combination of modelling (3‐D computational fluid dynamics (CFD)) and field measurement. Both model simulations and field measurements showed reversal of offshore flows at the back beach and creation of an onshore sediment transport potential. The influence of flow reversals on the beach‐dune transport system and foredune growth patterns has previously received little attention. Detailed wind flow measurements were made using an extensive array of mast‐mounted, 3‐D ultrasonic anemometers (50 Hz), arranged parallel to the dominant incident wind direction. Large eddy simulation (LES) of the offshore wind flow over the dune was conducted using the open‐source CFD tool openFOAM. The computational domain included a terrain model obtained by airborne LiDAR and detailed ground DGPS measurements. The computational grid (~22 million cells) included localized mesh refinement near the complex foredune terrain to capture finer details of the dune morphology that might affect wind flows on the adjacent beach. Measured and simulated wind flow are presented and discussed. The CFD simulations offer new insights into the flow mechanics associated with offshore winds and how the terrain steering of wind flow impacts on the geomorphological behaviour of the dune system. Simulation of 3‐D wind flows over complex terrain such as dune systems, presents a valuable new tool for geomorphological research, as it enables new insights into the relationship between the wind field and the underlying topography. The results show that offshore and obliquely offshore winds result in flow reversal and onshore directed winds at distances of up to 20 m from the embryo dune toe. The potential geomorphological significance of the findings are discussed and simple calculations show that incoming offshore and obliquely offshore winds with mean velocities over 13 m s?1 and 7 m s?1, respectively, have the potential to create onshore‐directed winds at the back beach with mean velocities above 3.3 m s?1. These are above the threshold of movement for dry sand and support previous conclusions about the significance of offshore winds in dune and beach budget calculations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
8.
The intertidal drainage channels on a macrotidal bar–trough (ridge‐and‐runnel) beach were monitored during a 17‐day survey. Type 1 channels were persistent, dominantly longshore systems essentially limited to the wide intertidal zone between mean high and low water neap tidal levels. The cumulative length of this channel type fluctuated as a function of topographically controlled through‐flow or flow impedance in troughs, and showed no correlation with the semi‐lunar tidal cycle. Smaller, ephemeral type 2 channels appeared as dominantly cross‐shore systems incising bars on the narrower upper and lower beach zones during spring tides. They disappeared during neap tides through infill by waves and aeolian activity. The only significant phase of type 1 channel mobility occurred during a brief moderate‐energy storm at the start of the survey. The effect of this mobility on beach morphology was inextricably linked to that of waves and currents. Meander bend migration, forced by wave‐ and longshore‐current‐induced migration of a bar during the storm, resulted in important but highly localized morphological change that was only a minor part of an irregular saw‐tooth pattern of change that affected the entire beach profile, and that was largely controlled by wave processes and longshore currents. The flow velocities in channels on this beach are too weak to generate the formation and longshore migration of high‐energy bedforms. Channel mobility and impact on beach morphology are expected to increase under storm conditions. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
9.
Analyses of shoreline and bathymetry change near Calais, northern coast of France, showed that shoreline evolution during the 20th century was strongly related with shoreface and nearshore bathymetry variations. Coastal erosion generally corresponds to areas of nearshore seabed lowering while shoreline progradation is essentially associated with areas of seafloor aggradation, notably east of Calais where an extensive sand flat experienced seaward shoreline displacement up to more than 300 m between 1949 and 2000. Mapping of bathymetry changes since 1911 revealed that significant variation in nearshore morphology was caused by the onshore and alongshore migration of a prominent tidal sand bank that eventually welded to the shore. Comparison of bathymetry data showed that the volume of the bank increased by about 10×107 m3 during the 20th century, indicating that the bank was acting as a sediment sink for some of the sand transiting alongshore in the coastal zone. Several lines of evidence show that the bank also represented a major sediment source for the prograding tidal flat, supplying significant amounts of sand to the accreting upper beach. Simulation of wave propagation using the SWAN wave model (Booij et al., 1999) suggests that the onshore movement of the sand bank resulted in a decrease of wave energy in the nearshore zone, leading to more dissipative conditions. Such conditions would have increased nearshore sediment supply, favoring aeolian dune development on the upper beach and shoreline progradation. Our results suggest that the onshore migration of nearshore sand banks may represent one of the most important, and possibly the primary mechanism responsible for supplying marine sand to beaches and coastal dunes in this macrotidal coastal environment. 相似文献
10.
Senapathi VENKATRAMANAN Thirunavukkarasu RAMKUMAR Irudhayanathan ANITHAMARY Govindaraj RAMESH 《国际泥沙研究》2011,(4):460-470
The distribution of grain size parameters along 11 km stretch of the beach sediments between Karikal and Nagore,reveals that the mean grain size exhibits a marked decreasing trend on either side of the mouth of the Tirumalairajanar River which flow from west to east.The sediments are mainly of medium to coarse grained,moderately sorted,near-symmetrical skewed to fine skewed and leptokurtic to mesokurtic in nature.Interrelationship of various parameters shows bimodal nature of sediments having dominance of medium to coarse sand.The major part of the sediment fall in a coarse to fine grained category(sand and silt).Based on the CM(Coarser one percentile value in micron) pattern,the sediment fall in rolling and suspension field.These factors includes the sediments discharged from the river mixes with offshore sediments and with the sediments eroded from a source rock.The effect of wave sorting, and the northward drifting of sediments by littoral current are understandable.Results indicate that the Tirumalairajanar River is the most important source for modern sediments in the study area.The agitation by waves is an important sorting mechanism in the study area,and the net sediment transport in the study area is northward.The findings are based on the grain sizes and also corroborated by shortterm observations of the beach sediment dynamics and transport during the monsoon and summer seasons between Karaikal and Nagore region. 相似文献
11.
Colin M. Sayers 《Geophysical Prospecting》2002,50(1):85-95
Elastic wave velocities in sandstones vary with stress due to the presence of discontinuities such as grain boundaries and microcracks within the rock. In the presence of non-hydrostatic stress fields the elastic wave velocities in sandstones often show significant stress-induced anisotropy. The elastic anisotropy due to any discontinuities within the rock can be written in terms of a second-rank and a fourth-rank tensor which quantify the effect on the elastic wave velocities of the orientation distribution and normal and shear compliances of the discontinuities. This allows elastic wave velocity measurements to be inverted to obtain the components of these tensors. Application of the method to ultrasonic velocity measurements made in a triaxial loading frame shows that a simple theory using only the second-rank tensor allows the P-wave stress-induced anisotropy to be predicted to reasonable accuracy from the S-wave anisotropy and vice versa, thus confirming the correctness of the underlying model. Deviations between the measurements and the predictions of this simplified theory are used to determine the ratio of the normal to shear compliance of the discontinuities. The discontinuities are found to be more compliant in shear than in compression. 相似文献
12.
A field experiment conducted on a sandy barred beach, situated on the southern part of the French Atlantic coastline, allowed us to investigate the impact of the intertidal bar on the wave-energy dissipation on the beach face in presence of a high-energy long-incoming swell (significant wave height of about 1.7 to 3.0 m in 56 m water depth and significant wave period about 12 s). Data were collected along three parallel cross-shore transects deployed along an intertidal ridge and runnel system. Wave heights in the inner surf zone are depth-limited, consistent with previous works, and the wave-energy dissipation in the inner surf zone appears to be relatively independent of the offshore energy level. On the other hand, the presence of the bar seems to scatter the data. In models of surf-zone hydrodynamics, wave-energy dissipation is often parameterized in terms of , the ratio of the sea-swell significant wave height to the local mean water depth. The observed values of are not constant along a cross-shore transect, and increase onshore. Furthermore, the observed values observed onshore the intertidal bar are higher than those observed outside the influence of the intertidal bar, and this cannot be fully explained by the different local beach slope.Responsible Editor: Iris Grabemann 相似文献
13.
John S. Bridge 《地球表面变化过程与地形》1977,2(4):401-416
Bed topography and grain size are predicted for steady, uniform flow in circular bends by consideration of the balance of fluid, gravity and frictional forces acting on bed load particles. Uniform flow pattern is adequately described by conventional hydraulic equations, with bed shear defined as that effectively acting on bed load grains. This analysis is used as a basis to predict bed topography and grain size for steady, non-uniform flow in non-circular bends (represented by a ‘sine-generated’ curve). The non-uniform flow pattern is calculated using the method of Engelund (1974a). Equilibrium bed form, hence sedimentary structure, is found by comparison of existing flow conditions with one of the schemes describing the hydraulic stability limits of the various bed forms. The model was compared with bankfull flow observations from a channel bend on the River South Esk, Scotland. Theoretical bed topography and velocity distribution were very close to the observed data. However, bed shear stress showed only a broad agreement, probably because of the use a constant friction coefficient value. Mean grain size distribution showed good agreement, but theory did not account adequately for gravel sizes in the talweg region and on the upstream, inner part of the bar, possibly due to theoretical underestimation of effective bed shear. Bed form and sedimentary structure are predicted well using the familiar stream power-grain size scheme. The behaviour of the model under unsteady uniform flow conditions in circular bends was analyzed, and suggests that any variation of grain size and bed topography with stage is likely to be limited to deeper parts of the channel. 相似文献
14.
Markov models offer an objective and quantitative method of assessing beach changes. For a stretch of the Holderness coast a beach classification scheme was devised and a probabilistic first order matrix model based on surveyed profile data was produced. This could describe and predict transitions between beach types and between different time periods. Different profile types dominated different coastal locations and seasonal variations were seen. In order to improve the accuracy of prediction throughout the year a second, ‘winter’, model was added to the original ‘summer’ one. Although the models had been prepared independently of wave conditions, a comparison of the wave record and beach transitions revealed that waves under 0·3–0·5 m high produced fairly static beaches; when waves were between 0·5 and 1·0 m the beach was more dynamic and variable, while waves over 1·0 m led to the depletion of the upper beach. This was broadly in accordance with published theory. Markov models have the advantage that they can be adjusted periodically if conditions change, and are thus useful for prediction on coasts for which no wave records exist. 相似文献
15.
We study erosion depth and sediment fluxes for wave-induced sheet-flow, and their dependency on grain size and streaming. Hereto, we adopt a continuous two-phase model, applied before to simulate sheet-flow of medium and coarse sized sand. To make the model applicable to a wider range of sizes including fine sand, it appears necessary to adapt the turbulence closure of the model. With an adapted formulation for grain–carrier flow turbulence interaction, good reproductions of measured erosion depth of fine, medium and coarse sized sand beds are obtained. Also concentration and velocity profiles at various phases of the wave are reproduced well by the model. Comparison of sediment flux profiles from simulations for horizontally uniform oscillatory flow as in flow tunnels and for horizontally non-uniform flow as under free surface waves, shows that especially for fine sand onshore fluxes inside the sheet-flow layer increase under influence of progressive wave effects. This includes both the current-related and the wave-related contribution to the period-averaged sheet-flow sediment flux. The simulation results are consistent with trends for fine and medium sized sediment flux profiles observed from tunnel and flume experiments. This study shows that the present two-phase model is a valuable instrument for further study and parameterization of sheet-flow layer processes. 相似文献
16.
Within the context of a warming climate, there are wide and increasing concerns about the way beaches respond to different wave energy environments. However, behavioural differences in changes in beach elevation contours (including shorelines) in different wave energy environments remain unknown. Thus, it is unilateral to evaluate the changes in beaches based on a single elevation contour (e.g. shoreline) in coastal engineering and management applications. In this study, based on the collected shoreline and wave energy data of two international beaches, as well as the measured beach elevation contour data from Yintan Beach and the corresponding wave energy data simulated by Xbeach, our results show that frequency distributions of beach elevation contour changes exhibit distinct features under different wave energy environments. Under high wave energy environments, the frequency distributions of beach elevation contour changes show a Gaussian distribution. However, frequency distributions of beach elevation contour changes present a power law, intermediate between the logarithmic and Gaussian distributions under low and moderate wave energy environments, respectively. Furthermore, the conceptual model of beach elevation contour changes constructed by this study indicates that the relative importance of the wave energy and sediment resistance determines this phenomenon. © 2020 John Wiley & Sons Ltd 相似文献
17.
成岩作用是影响砂岩声波速度的地质因素之一,定量表征压实和胶结作用的砂岩声波速度岩石物理模型具有重要的理论和实践应用意义.选取视压实率和视胶结率定量表征砂岩成岩作用,通过建立视压实率与颗粒配位数的关系将压实作用的影响引入修正的定量表征胶结作用的CCT模型,最终建立了一种能够定量表征压实和胶结作用对砂岩声波速度影响的岩石物理模型.理论考察发现,随胶结率的增大,岩石声波速度首先迅速增大,随后趋于稳定;随视压实率增大,岩石声波速度同样逐渐增大,当胶结率较大时声波速度变化更为明显.为了验证该声波速度模型,分别对人造砂岩和天然样品进行了声波速度实验观测,结果表明：实验结果与理论分析的趋势吻合良好.该模型易于使用,能够为应用地震和测井资料识别有利储层、定量评价孔隙度以及开展横波速度预测等应用提供理论基础. 相似文献
18.
Mud deposits near sandy beaches, found throughout the world, are of scientific and societal interest as they form important natural sea defenses by efficiently damping storm waves. A multi-national field experiment to study these phenomena was performed offshore Cassino beach in southern Brazil starting in 2004. This experiment aimed to investigate the formation of an offshore mud deposit, to characterize wave attenuation over potentially mobile muddy bottoms, and to evaluate the performance of models for wave transformation over heterogeneous beds through the measurement of water waves, near-bottom currents, bathymetry, and changes in bottom sediment characteristics. The main instrumentation was a set of wave sensors deployed in a transect from the shoreline across sandy and muddy deposits offshore to a depth of 25 m. Additional sensors, including current meters and optical backscatter sensors, were concentrated at stations in the middle of the mud deposit and in the surf zone to document aspects of the wave boundary layer and lutocline dynamics. This fieldwork also involved the geological and geotechnical characterization of the mud deposit using seismic equipment, echo-sounders, cores, surficial sampling and an in-situ density meter. These sediment samples were subsequently analyzed for density, grain size distribution, mineralogy, rheology and sedimentary structures. In addition, video and radar monitoring equipment were installed to measure the long-term aspects of surf zone damping by fluid mud and any associated morphodynamic responses. This paper provides a summary of environmental conditions monitored during the experiment and describes the major findings of the various investigations. Although data collection was more difficult than anticipated and dramatic wave attenuation involving the onshore transport of fluid mud into the surf zone region was not observed during the instrumented interval, the new methodologies developed and comprehensive observations obtained during this effort are being used to improve our understanding of shoaling wave dynamics and sediment transport in the coastal zone in regions with significant cohesive sediment deposits. 相似文献
19.
This study investigates the recovery capabilities of a single-barred beach in the Pacific Mexican coast before and after the 2015–2016 El Niño winter. Concurrent hydrodynamic and morphological data collected over a 3-year period (August 2014–2017) were analysed to determine the subaerial-subtidal volumetric exchange and cross-shore subtidal sandbar migrations, in relation to the incident wave forcing. The beach presented a seasonal seaward and landward sandbar migration cycle. The sandbar migrated offshore during the energetic waves between November and February, and onshore during the milder wave period in spring, until welding to the subaerial beach around May. The transfer of sediment towards the subaerial section continued over the summer, reaching a complete recovery by September/October. Prior to El Niño, the subaerial beach successfully recovered by the end of summer 2015 through the landward sandbar migration process. The 2015–2016 energetic winter waves caused a subaerial volume loss of ~ 140 m3 m?1 (from October 2015 to March 2016), more than twice the amount eroded in the other winters, and the sandbar moved further offshore and to deeper depths (3–4 m) than the winter before. In addition, the energetic 2015–2016 winter waves lasted for 2 months longer than in other years, making the 2016 spring shorter. Consequently, during the onshore migration, the sandbar was unable of reaching shallow depths, and a large portion of sand remained in the subtidal beach. The subaerial beach recovered 60 and 65% of the loss in the 2016 and 2017 summers, respectively. It is concluded that the landward migration process of the sandbar during the spring is critical to ensure a full subaerial beach recovery over the mild wave period in summer. The recovery capabilities of the subaerial beach will depend on the cross-shore distance and depth where the sandbar is located, and on the duration of mild wave conditions required for the sandbar to migrate onshore. 相似文献
20.
A sandy beach in the south of Portugal (Faro beach, Ria Formosa) was surveyed from the dune crest seaward to 15 m depth 20 times over a period of 26 months. Wave time‐series between surveys were analysed to obtain relationships between wave height and vertical profile variations and to define wave thresholds for important morphological changes. Results show that the active zone of the profile lies between 5 m above and 10·4 m below mean sea level, and that there are clear cross‐shore differences in the vertical variability of the profile. Based on the pattern of vertical variability, the profile was divided into four cross‐shore sectors: A (berm), 20–80 m from the profile origin; B (sub‐tidal terrace), 80–170 m; C (long‐shore bar), 170–360 m; and D, 360–700 m. The relationship between the modulus of the maximum vertical change in each sector and the 99th percentile of significant wave height between surveys was always significant. Calculated thresholds for significant wave height generating important morphological changes were 2·3 m in sector A, 3·2 m in sectors B and C, and 4·1 m in sector D. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献