scholarly journals Large-Scale Patterns in Hurricane-Driven Shoreline Change

2012 ◽  
pp. 127-138 ◽  
Author(s):  
Eli D. Lazarus ◽  
Andrew D. Ashton ◽  
A. Brad Murray
Keyword(s):  
Large Scale ◽  
Shoreline Change

scholarly journals Challenges and Opportunities in Coastal Shoreline Prediction

2021 ◽  
Vol 8 ◽  
Author(s):  
Kristen D. Splinter ◽  
Giovanni Coco
Keyword(s):  
Large Scale ◽  
Southern Oscillation ◽  
Shoreline Change ◽  
Sandy Beaches ◽  
Water Levels ◽  
Current State ◽  
Challenges And Opportunities ◽  
Future Challenges ◽  
Shoreline Prediction

Sandy beaches comprise approximately 31% of the world's ice-free coasts. Sandy coastlines around the world are continuously adjusting in response to changing waves and water levels at both short (storm) and long (climate-driven, from El-Nino Southern Oscillation to sea level rise) timescales. Managing this critical zone requires robust, advanced tools that represent our best understanding of how to abstract and integrate coastal processes. However, this has been hindered by (1) a lack of long-term, large-scale coastal monitoring of sandy beaches and (2) a robust understanding of the key physical processes that drive shoreline change over multiple timescales. This perspectives article aims to summarize the current state of shoreline modeling at the sub-century timescale and provides an outlook on future challenges and opportunities ahead.

scholarly journals Modeling large-scale shoreline change caused by complex bathymetry in low-angle wave climates

2017 ◽  
Vol 383 ◽  
pp. 55-64 ◽  
Author(s):  
Patrick W. Limber ◽  
Peter N. Adams ◽  
A. Brad Murray
Keyword(s):  
Large Scale ◽  
Shoreline Change

scholarly journals SHORELINE SAND WAVES AND BEACH NOURISHMENTS

2011 ◽  
Vol 1 (32) ◽  
pp. 102
Author(s):  
N. Van den Berg ◽  
A. Falqués ◽  
F. Ribas
Keyword(s):  
Large Scale ◽  
Incidence Angle ◽  
Wave Train ◽  
Shoreline Change ◽  
Sand Wave ◽  
High Angle ◽  
Wave Instability ◽  
Littoral Drift ◽  
Sand Waves ◽  
Change Models

The effects of the feedback between the changing coastal morphology and the wavefield on the generation and propagation of large scale (O(1-10 km)) shoreline sand waves is examined with a quasi-2D morphodynamic model. Traditional shoreline change models do not include this feedback and are only able to describe diffusion of shoreline sand waves and furthermore they are unable to describe migration. It is found with the present model that if there is a dominant littoral drift, the feedback causes downdrift migration of coastline features no matter if they grow or decay. Consistently with previous studies, simulations show that a rectilinear coastline becomes unstable and sand waves tend to grow spontaneously from random perturbations, if the wave incidence angle is larger then about 42o (θc) at the depth of closure (high angle wave instability). The initial wavelengths at which the sand waves develop are 2-3 km and this is similar to previous linear stability analysis. The implications of high angle wave instability for beach nourishments are investigated. The nourished shoreline retreats initially due to cross-shore transport because the nourished profile is steeper than the equilibrium profile. When a dominant littoral drift is present, the nourishment also migrates downdrift. If the wave angle at the depth of closure is below θc the alongshore transport contributes to the diffusion of the nourishment. However, if the angle is above θc (constant high angle wave conditions) the diffusion is reversed and the nourishment can trigger the formation of a shoreline sand wave train. Numerical experiments changing the proportion of ‘high angle waves’ and ‘low angle waves’ in the wave climate show that relatively small proportions of low angle waves slow down the growth of sand waves. These simulations with more realistic wave climates show shoreline sand waves that migrate downdrift maintaining more or less the same amplitude for years.

Modeling the effects of wave climate and sediment supply variability on large-scale shoreline change

2010 ◽  
Vol 273 (1-4) ◽  
pp. 127-140 ◽  
Author(s):  
Peter Ruggiero ◽  
Maarten Buijsman ◽  
George M. Kaminsky ◽  
Guy Gelfenbaum
Keyword(s):  
Large Scale ◽  
Shoreline Change ◽  
Wave Climate ◽  
Sediment Supply

scholarly journals TIME SCALE FOR MODELING BEACH CHANGE

1986 ◽  
Vol 1 (20) ◽  
pp. 88 ◽  
Author(s):  
Masahiro Ito ◽  
Yoshito Tsuchiya
Keyword(s):  
Time Scale ◽  
Large Scale ◽  
Shoreline Change ◽  
Scale Model ◽  
Experimental Conditions ◽  
Equilibrium Beach Profile ◽  
Beach Processes ◽  
Allowable Range ◽  
Set Up ◽  
Relationship Of

A time scale in the similarity of beach change between model and prototype in transitional beach processes from an initial even slope to an equilibrium is developed using a series of small- and large-scale experiments in which the experimental conditions were set up with the scale-model relationship by the authors (1984). The time scale is obtained empirically as a function of experimental scale. Applied the proposed time scale and the scale-model relationship to model experiments, similarity of morphological beach change such as shoreline change and relative breaker point was well reproduced within the allowable range of experimental error. A semi-theoretical time scale is obtained from the continuity equation, the sediment transport rate, and the scale-model relationship of equilibrium beach profile in two-dimensional beach change. The relation between experimental and semi-theoretical time scale is discussed.

scholarly journals A DSAS-based study of central shoreline change in Jiangsu over 45 years

2021 ◽  
Vol 4 (1) ◽  
pp. 115-128
Author(s):  
Yuan Song ◽  
Yongming Shen ◽  
Ruofan Xie ◽  
Jialin Li
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Shoreline Change ◽  
Sand Ridge ◽  
Change Rate ◽  
Shoreline Evolution ◽  
Quantitative Monitoring ◽  
Length Changes ◽  
Analysis System ◽  
End Point Rate

A large-scale sand ridge group is distributed in the central Jiangsu coastal area, and a deposition muddy sea bank was developed in the nearshore area. Quantitative monitoring of coastline changes is of great significance for tidal beach development and protection. The shorelines of the central coast of Jiangsu within six periods (1973–2018) were extracted in this study, and their length changes over the years were analyzed. The Digital Shoreline Analysis System (DSAS) was employed to generate a cross section perpendicular to the baseline and calculate the linear regression rate (LRR) of the shoreline, changes in end point rate (EPR), and net shoreline movement (NSM), based on which the shoreline change features were analyzed. The DSAS results indicated that the shorelines in the study area maintained fluctuating growth and presented a continuous advancing trend towards the sea. From the changes in shoreline evolution distance during 1973–2018, the advancing shorelines in the study area accounted for over 50% of the total shorelines and presented first rising and then declining trends with the period of 2003–2013 taken as the time boundary. The average shoreline change rate was 207 m/year, and the periods with the highest change degrees were 1983–1993 and 1993–2013. The shoreline change tended to be stable during 2013–2018, and only a few estuaries and ports underwent obvious erosion and sedimentation.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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