Bedform dimensions and migration rates under shoaling and breaking waves

Wave‐formed sand ripples at Duck, North Carolina

“…Even if LWR are orbital ripples, they are still particularly perplexing because of their low slopes. Osborne and Vincent [1993], Gallagher et al [1998], Thornton et al [1998], and others have reported bed forms with similar lengths, but the heights and slopes that we observed were lower than most previous observations. This could simply result from the relatively better ability of the MTA to measure low bed form heights.…”

Wave‐formed sand ripples at Duck, North Carolina

“…Even if LWR are orbital ripples, they are still particularly perplexing because of their low slopes. Osborne and Vincent [1993], Gallagher et al [1998], Thornton et al [1998], and others have reported bed forms with similar lengths, but the heights and slopes that we observed were lower than most previous observations. This could simply result from the relatively better ability of the MTA to measure low bed form heights.…”

Observations of bed level change in a saturated surf zone

“…Supplementary evidence for this hypothesis includes that heights of the bed oscillations in the altimeter time series (approximately 0.5–2.0 cm) showed reasonable agreement with predicted ripple heights (generated from Nielsen 's [1981] model) and were similar to heights of small‐scale ripples in field observations made by Dingler and Inman [1976], Vincent and Osborne [1993] and Crawford and Hay [2001], under similar wave energy conditions. Values of the Shields parameter generated from velocity values in the present study (near to twice the critical threshold for mobilization of sediment) suggest the formation of rolling grain or vortex ripples [ Fredsoe and Deigaard , 1992].…”

“…Values of the Shields parameter generated from velocity values in the present study (near to twice the critical threshold for mobilization of sediment) suggest the formation of rolling grain or vortex ripples [ Fredsoe and Deigaard , 1992]. Migration of these types of bedform has been observed by Dingler and Inman [1976], Vincent and Osborne [1993], Hanes et al [1997], Traykovski et al [1999] and Crawford and Hay [2001]. Finally, in results of a separate field experiment conducted at Teignmouth (UK), Saulter et al [2000] showed altimeter traces corresponding with migratory and static ripples (for mobility numbers less than 40) identified in rotating side‐scan sonar images.…”

Geometry and dynamics of wave ripples in the nearshore zone of a coarse sandy beach

“…Similar to previous field investigations in sandy nearshores [ Vincent and Osborne , 1993; Thornton et al , 1998; Hanes et al , 2001], our observations of the bed morphology fall into two main classes: “small” wave ripple forms (SWR) with wave lengths less than 0.5 m and “large” wave ripple forms (LWR) with wave lengths larger than 0.5 m (including plane bed). The overwhelming majority of the ripples observed were SWR; LWR and plane bed conditions were only observed on a few occasions, under quite energetic surf zone conditions during which the SRP struggled to return a reliable image of the sea bed.…”

Wave‐formed sand ripples at Duck, North Carolina

“…Even if LWR are orbital ripples, they are still particularly perplexing because of their low slopes. Osborne and Vincent [1993], Gallagher et al [1998], Thornton et al [1998], and others have reported bed forms with similar lengths, but the heights and slopes that we observed were lower than most previous observations. This could simply result from the relatively better ability of the MTA to measure low bed form heights.…”

Observations of bed level change in a saturated surf zone

“…Supplementary evidence for this hypothesis includes that heights of the bed oscillations in the altimeter time series (approximately 0.5–2.0 cm) showed reasonable agreement with predicted ripple heights (generated from Nielsen 's [1981] model) and were similar to heights of small‐scale ripples in field observations made by Dingler and Inman [1976], Vincent and Osborne [1993] and Crawford and Hay [2001], under similar wave energy conditions. Values of the Shields parameter generated from velocity values in the present study (near to twice the critical threshold for mobilization of sediment) suggest the formation of rolling grain or vortex ripples [ Fredsoe and Deigaard , 1992].…”

“…Values of the Shields parameter generated from velocity values in the present study (near to twice the critical threshold for mobilization of sediment) suggest the formation of rolling grain or vortex ripples [ Fredsoe and Deigaard , 1992]. Migration of these types of bedform has been observed by Dingler and Inman [1976], Vincent and Osborne [1993], Hanes et al [1997], Traykovski et al [1999] and Crawford and Hay [2001]. Finally, in results of a separate field experiment conducted at Teignmouth (UK), Saulter et al [2000] showed altimeter traces corresponding with migratory and static ripples (for mobility numbers less than 40) identified in rotating side‐scan sonar images.…”

Geometry and dynamics of wave ripples in the nearshore zone of a coarse sandy beach

“…Similar to previous field investigations in sandy nearshores [ Vincent and Osborne , 1993; Thornton et al , 1998; Hanes et al , 2001], our observations of the bed morphology fall into two main classes: “small” wave ripple forms (SWR) with wave lengths less than 0.5 m and “large” wave ripple forms (LWR) with wave lengths larger than 0.5 m (including plane bed). The overwhelming majority of the ripples observed were SWR; LWR and plane bed conditions were only observed on a few occasions, under quite energetic surf zone conditions during which the SRP struggled to return a reliable image of the sea bed.…”

Wave‐formed sand ripples at Duck, North Carolina

“…Even if LWR are orbital ripples, they are still particularly perplexing because of their low slopes. Osborne and Vincent [1993], Gallagher et al [1998], Thornton et al [1998], and others have reported bed forms with similar lengths, but the heights and slopes that we observed were lower than most previous observations. This could simply result from the relatively better ability of the MTA to measure low bed form heights.…”

Observations of bed level change in a saturated surf zone

“…Supplementary evidence for this hypothesis includes that heights of the bed oscillations in the altimeter time series (approximately 0.5–2.0 cm) showed reasonable agreement with predicted ripple heights (generated from Nielsen 's [1981] model) and were similar to heights of small‐scale ripples in field observations made by Dingler and Inman [1976], Vincent and Osborne [1993] and Crawford and Hay [2001], under similar wave energy conditions. Values of the Shields parameter generated from velocity values in the present study (near to twice the critical threshold for mobilization of sediment) suggest the formation of rolling grain or vortex ripples [ Fredsoe and Deigaard , 1992].…”

“…Values of the Shields parameter generated from velocity values in the present study (near to twice the critical threshold for mobilization of sediment) suggest the formation of rolling grain or vortex ripples [ Fredsoe and Deigaard , 1992]. Migration of these types of bedform has been observed by Dingler and Inman [1976], Vincent and Osborne [1993], Hanes et al [1997], Traykovski et al [1999] and Crawford and Hay [2001]. Finally, in results of a separate field experiment conducted at Teignmouth (UK), Saulter et al [2000] showed altimeter traces corresponding with migratory and static ripples (for mobility numbers less than 40) identified in rotating side‐scan sonar images.…”

Geometry and dynamics of wave ripples in the nearshore zone of a coarse sandy beach

“…Similar to previous field investigations in sandy nearshores [ Vincent and Osborne , 1993; Thornton et al , 1998; Hanes et al , 2001], our observations of the bed morphology fall into two main classes: “small” wave ripple forms (SWR) with wave lengths less than 0.5 m and “large” wave ripple forms (LWR) with wave lengths larger than 0.5 m (including plane bed). The overwhelming majority of the ripples observed were SWR; LWR and plane bed conditions were only observed on a few occasions, under quite energetic surf zone conditions during which the SRP struggled to return a reliable image of the sea bed.…”