ช่วยเราหน่อย มันเป็นศัพท์เฉพาะ แปลมาแล้วเราเรียบเรียงไม่ถูกอ่ะ ใครก็ได้ช่วยที พลีสสสส
Many beaches are characterised by having steep upper slopes, flat low-tide terraces, and mixed or bimodal sediment
distributions. This study compares the surf zone hydrodynamic and sediment transport processes of these two
dynamically different regimes on the beach at Teignmouth (UK) as part of the COAST3D project. In-situ
measurements were made using pressure transducers, electromagnetic current meters and optical backscatter sensors
simultaneously on the steep part of the beach (slope 1/10, D501.1mm) and on the terrace (slope 1/100, D500.25mm)
during a range of incident wave conditions (Hb0.25–0.75m).
The steep upper beach was characterised by: plunging breakers, high wave height/water depth (g) values, large gravity
band cross-shore velocity variance, a well-developed subharmonic, strong undertow, high suspended sediment
concentrations, and sediment transport dominated by a strong mean offshore component.
The shallow shelving terrace was characterised by spilling breakers, low g values, weak undertow, gravity velocity
variance decreasing shoreward, infragravity cross-shore velocity variance increasing shoreward, and stronger longshore
currents than undertow. Mean suspended sediment concentrations on the terrace were an order of magnitude less than
on the steep beach. The oscillatory cross-shore components of transport were onshore in the incident wave band but
increasingly dominated by the infragravity band in progressively shallower water. Longshore sediment transport rates
on the terrace were large compared to cross-shore transport rates.
The measurements suggest that the dynamics of the terrace/steep beach exhibit characteristics of separate dissipative/
reflective sites. However, interaction between the different regions does occur. In particular, the low tide terrace acts to
reduce the wave height that is capable of reaching the steep beach, thereby protecting it to some degree from erosion.
r 2004 Elsevier Ltd. All rights reserved.
ใครก็ได้ช่วยเราแปลอังกฤษเป็นไทยหน่อยซิ T_T
Many beaches are characterised by having steep upper slopes, flat low-tide terraces, and mixed or bimodal sediment
distributions. This study compares the surf zone hydrodynamic and sediment transport processes of these two
dynamically different regimes on the beach at Teignmouth (UK) as part of the COAST3D project. In-situ
measurements were made using pressure transducers, electromagnetic current meters and optical backscatter sensors
simultaneously on the steep part of the beach (slope 1/10, D501.1mm) and on the terrace (slope 1/100, D500.25mm)
during a range of incident wave conditions (Hb0.25–0.75m).
The steep upper beach was characterised by: plunging breakers, high wave height/water depth (g) values, large gravity
band cross-shore velocity variance, a well-developed subharmonic, strong undertow, high suspended sediment
concentrations, and sediment transport dominated by a strong mean offshore component.
The shallow shelving terrace was characterised by spilling breakers, low g values, weak undertow, gravity velocity
variance decreasing shoreward, infragravity cross-shore velocity variance increasing shoreward, and stronger longshore
currents than undertow. Mean suspended sediment concentrations on the terrace were an order of magnitude less than
on the steep beach. The oscillatory cross-shore components of transport were onshore in the incident wave band but
increasingly dominated by the infragravity band in progressively shallower water. Longshore sediment transport rates
on the terrace were large compared to cross-shore transport rates.
The measurements suggest that the dynamics of the terrace/steep beach exhibit characteristics of separate dissipative/
reflective sites. However, interaction between the different regions does occur. In particular, the low tide terrace acts to
reduce the wave height that is capable of reaching the steep beach, thereby protecting it to some degree from erosion.
r 2004 Elsevier Ltd. All rights reserved.