AE Hay

AM Crawford

Antony Thorpe

AS Ngasuru

BE Jaffe

BG Ruessink

CE Vincent

DJ Sherman

EB Thornton

EL Gallagher

G Masselink

Gerd Masselink

HE Clifton

JA Bailard

Jon Miles

JRL Allen

JS Doucette

KR Dyer

LB Clarke

LD Wright

M Davidson

MA Davidson

MJ Austin

MS Yalin

P Blondeaux

P Nielsen

P Traykovski

Paul Russell

RA Bagnold

S Elgar

T Butt

Ocean Dynamics

Abstract
          Field measurements of wave ripples and megaripples were made with a Sand Ripple Profiler in the surf and shoaling zones of a sandy macrotidal dissipative beach at Perranporth, UK in depths 1–6 m and significant wave heights up to 2.2 m. A frequency domain partitioning approach allowed quantification of height (η), length (λ) and migration rate of ripples and megaripples. Wave ripples with heights up to 2 cm and wavelengths ∼20 cm developed in low orbital velocity conditions (u
            m &lt; 0.65 m/s) with mobility number ψ &lt; 25. Wave ripple heights decreased with increasing orbital velocity and were flattened when mean currents were &gt;0.1 m/s. Wave ripples were superimposed on top of megaripples (η = 10 cm, λ = 1 m) and contributed up to 35 % of the total bed roughness. Large megaripples with heights up to 30 cm and lengths 1–1.8 m developed when the orbital velocity was 0.5–0.8 m/s, corresponding to mobility numbers 25–50. Megaripple heights and wavelengths increased with orbital velocity but reduced when mean current strengths were &gt;0.15 m/s. Wave ripple and megaripple migrations were generally onshore directed in the shoaling and surf zones. Onshore ripple migration rates increased with onshore-directed (+ve) incident wave skewness. The onshore migration rate reduced as offshore-directed mean flows (undertow) increased in strength and reached zero when the offshore-directed mean flow was &gt;0.15 m/s. The migration pattern was therefore linked to cross-shore position relative to the surf zone, controlled by competition between onshore-directed velocity skewness and offshore-directed mean flow.</jats:p

Crossref

Observations of bedforms on a dissipative macrotidal beach

Springer - Publisher Connector

Miles, Jon

Thorpe, Antony

Russell, Paul

Masselink, Gerd

PEARL (Univ. of Plymouth)

https://link.springer.com/content/pdf/10.1007%2Fs10236-013-0677-2.pdf

Observations of bedforms on a dissipative macrotidal beach

Abstract

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Crossref

Springer - Publisher Connector

Springer - Publisher Connector

PEARL (Univ. of Plymouth)