Meeting:Abstract 2011 CSDMS meeting-034: Difference between revisions
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|CSDMS meeting first name= | |CSDMS meeting first name=Brad | ||
|CSDMS meeting last name= | |CSDMS meeting last name=Murray | ||
|CSDMS meeting institute= | |CSDMS meeting institute=Duke Univ. | ||
|CSDMS meeting city= | |CSDMS meeting city=Durham | ||
|CSDMS meeting state= | |CSDMS meeting state=North Carolina | ||
|CSDMS meeting country= | |CSDMS meeting country=United States | ||
|CSDMS meeting email address= | |CSDMS meeting email address=abmurray@duke.edu | ||
|CSDMS meeting phone=919 681-5069 | |||
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|CSDMS meeting abstract title=Don’t upscale the coastline: scales of cumulative change emerge | |||
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|CSDMS meeting coauthor first name abstract=Eli | |||
|CSDMS meeting coauthor last name abstract=Lazarus | |||
|CSDMS meeting coauthor institute / Organization=Cardiff Univ. | |||
|CSDMS meeting coauthor town-city=Cardiff, Wales | |||
|CSDMS meeting coauthor country=UK | |||
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|CSDMS meeting coauthor first name abstract=Andrew | |||
|CSDMS meeting coauthor last name abstract=Ashton | |||
|CSDMS meeting coauthor institute / Organization=Wood Hole Oceanographic Inst. | |||
|CSDMS meeting coauthor town-city=Woods Hole | |||
|State=Massachusetts | |||
|CSDMS meeting coauthor country=United States | |||
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|CSDMS meeting coauthor first name abstract=Sarah | |||
|CSDMS meeting coauthor last name abstract=Tebbens | |||
|CSDMS meeting coauthor institute / Organization=Wright State University | |||
|CSDMS meeting coauthor town-city=Dayton | |||
|State=Ohio | |||
|CSDMS meeting coauthor country=United States | |||
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|CSDMS meeting coauthor first name abstract=Stephen | |||
|CSDMS meeting coauthor last name abstract=Burroughs | |||
|CSDMS meeting coauthor institute / Organization=Univ. of Tampa | |||
|CSDMS meeting coauthor town-city=Tampa | |||
|State=Florida | |||
|CSDMS meeting coauthor country=United States | |||
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|CSDMS meeting abstract=Analyzing patterns of shoreline change between repeated LIDAR surveys reveals disparate styles of behavior on different temporal and spatial scales (Lazarus and Murray, GRL 2007; Lazarus, Ashton, Murray, Tebbens, and Burroughs, in review). We use wavelet analysis to investigate the mean variance (or spectral power) of cross-shore shoreline change, as well as the alongshore locations exhibiting high variance, across a range of scales. The time spans between surveys range from one to 12 years. On scales of a kilometer and less, the variance of shoreline change does not increase with the length of time between surveys. On these spatial scales, significant changes in shoreline location tend to occur in localized zones, and these zones shift from one time period to another rather than accumulating. Incidentally, the variance across these scales also exhibits a power-law behavior, even though different processes are known to dominate shoreline change on different scales within the range from 10-103 m. However, on scales larger than a kilometer, a peak in the variance appears, and both the magnitude of the variance and the alongshore scale of maximum variance increases over time; on these scales of a few to ten kilometers, shoreline changes do accumulate. | |||
We interpret these observations as follows: On scales of a kilometer and less, each wave event creates an alongshore-heterogeneous pattern of shoreline change, with the alongshore locations of accentuated shoreline change depending on the characteristics of the waves (height, period, deep-water approach angle) and how those waves interact with heterogeneities on the seafloor—bathymetric features on the inner continental shelf are associated with shoreline change on the kilometer scale (List REFSXXX), and those in the surf zone and swash zones produce changes with alongshore scales on the order of one hundred meters and ten meters, respectively . Repeating such shoreline changes over many wave events superimposes essentially independent patterns of change, with effectively no memory of previous changes. The cumulative changes on scales of a few to ten kilometers, in contrast, suggest a diffusion of plan-view coastline shape; the relationship between the length scales of the variance peak over different time scales are consistent with diffusion, given estimates of effective diffusivity for this coastline (REF ANDREW, JORDAN). Apparently, on large alongshore length scales, the residual alongshore sediment flux that emerges from the many disparate wave events and associated complicated smaller scale patterns of sediment transport can be treated as related to shoreline orientation (the gradient in shoreline location)—the way that a long-term, large-scale, gradient-related flux of soil creep on hillslopes emerges from the complicated smaller-scale patterns of tree throw, gopher burrows, etc.. | |||
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|CSDMS meeting first hydrological choice=I am not interested | |CSDMS meeting first hydrological choice=I am not interested | ||
|CSDMS meeting first terrestrial choice= | |CSDMS meeting first terrestrial choice=CHILD | ||
|CSDMS meeting first coastal choice= | |CSDMS meeting first coastal choice=SWAN | ||
|CSDMS meeting first marine choice= | |CSDMS meeting second coastal choice=CEM | ||
|CSDMS meeting first carbonate choice= | |CSDMS meeting first marine choice=Delft3D | ||
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|CSDMS arrange hotel=Yes | |CSDMS arrange hotel=Yes | ||
|Check in date=2011/10/28 | |Check in date=2011/10/28 | ||
|Check out date=2011/10/ | |Check out date=2011/10/31 | ||
|Share a room= | |Share a room=No | ||
|CSDMS meeting dinner=No | |CSDMS meeting dinner=No | ||
|CSDMS meeting funding=Registration, Air travel, Lodging, Per diem | |CSDMS meeting funding=Registration, Air travel, Lodging, Per diem | ||
|CSDMS registration support= | |CSDMS registration support=lsdkf | ||
|CSDMS airtravel support= | |CSDMS airtravel support=adfas | ||
|CSDMS lodging support= | |CSDMS lodging support=adfas | ||
|CSDMS perdiem support= | |CSDMS perdiem support=fwsdf | ||
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Revision as of 09:23, 13 September 2011
Browse abstracts
Don’t upscale the coastline: scales of cumulative change emerge
[[Image:|300px|right|link=File:]]Analyzing patterns of shoreline change between repeated LIDAR surveys reveals disparate styles of behavior on different temporal and spatial scales (Lazarus and Murray, GRL 2007; Lazarus, Ashton, Murray, Tebbens, and Burroughs, in review). We use wavelet analysis to investigate the mean variance (or spectral power) of cross-shore shoreline change, as well as the alongshore locations exhibiting high variance, across a range of scales. The time spans between surveys range from one to 12 years. On scales of a kilometer and less, the variance of shoreline change does not increase with the length of time between surveys. On these spatial scales, significant changes in shoreline location tend to occur in localized zones, and these zones shift from one time period to another rather than accumulating. Incidentally, the variance across these scales also exhibits a power-law behavior, even though different processes are known to dominate shoreline change on different scales within the range from 10-103 m. However, on scales larger than a kilometer, a peak in the variance appears, and both the magnitude of the variance and the alongshore scale of maximum variance increases over time; on these scales of a few to ten kilometers, shoreline changes do accumulate.
We interpret these observations as follows: On scales of a kilometer and less, each wave event creates an alongshore-heterogeneous pattern of shoreline change, with the alongshore locations of accentuated shoreline change depending on the characteristics of the waves (height, period, deep-water approach angle) and how those waves interact with heterogeneities on the seafloor—bathymetric features on the inner continental shelf are associated with shoreline change on the kilometer scale (List REFSXXX), and those in the surf zone and swash zones produce changes with alongshore scales on the order of one hundred meters and ten meters, respectively . Repeating such shoreline changes over many wave events superimposes essentially independent patterns of change, with effectively no memory of previous changes. The cumulative changes on scales of a few to ten kilometers, in contrast, suggest a diffusion of plan-view coastline shape; the relationship between the length scales of the variance peak over different time scales are consistent with diffusion, given estimates of effective diffusivity for this coastline (REF ANDREW, JORDAN). Apparently, on large alongshore length scales, the residual alongshore sediment flux that emerges from the many disparate wave events and associated complicated smaller scale patterns of sediment transport can be treated as related to shoreline orientation (the gradient in shoreline location)—the way that a long-term, large-scale, gradient-related flux of soil creep on hillslopes emerges from the complicated smaller-scale patterns of tree throw, gopher burrows, etc..
