A three-dimensional laboratory investigation of beach morphology change during a storm event

Geomorphology ◽  
2020 ◽  
Vol 363 ◽  
pp. 107224
Author(s):  
Ramy Y. Marmoush ◽  
Ryan P. Mulligan
Keyword(s):  
Laboratory Investigation ◽  
Three Dimensional ◽  
Storm Event ◽  
Beach Morphology ◽  
Morphology Change

scholarly journals Beach Morphology Change Caused by Overwash on Yokosuka Coast

2007 ◽  
Vol 54 ◽  
pp. 681-685
Author(s):  
Xuan Tinh NGUYEN ◽  
Hitoshi TANAKA
Keyword(s):  
Beach Morphology ◽  
Morphology Change

scholarly journals Decadal trends in beach morphology on the east coast of South Africa and likely causative factors

2012 ◽  
Vol 12 (8) ◽  
pp. 2515-2527 ◽  
Author(s):  
S. Corbella ◽  
D. D. Stretch
Keyword(s):  
South Africa ◽  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
Storm Event ◽  
Wave Direction ◽  
Peak Period ◽  
Beach Morphology ◽  
Shoreline Changes ◽  
Causative Factors

Abstract. Sandy shorelines are dynamic with constant changes that can cause hazards in developed areas. The causes of change may be either natural or anthropogenic. This paper evaluates evidence for shoreline changes and their causative factors using a case study on the east coast of South Africa. Beach morphology trends were found to be location-specific, but overall the beaches show a receding trend. It was hypothesized that wave, tide, sea level and wind trends as well as anthropogenic influences are causative factors, and their contributions to shoreline changes were evaluated. Maximum significant wave heights, average wave direction, peak period and storm event frequencies all show weak increasing trends, but only the increases in peak period and wave direction are statistically significant. The chronic beach erosion cannot be attributed to wave climate changes since they are still too small to explain the observations. Instead, the impacts of sea level rise and reductions in the supply of beach sediments are suggested as the main causative factors. The analysis also identifies a trend in the frequency of severe erosion events due to storms that coincide with a 4.5-yr extreme tide cycle, which demonstrates the potential impact of future sea level rise.

scholarly journals Can MERRA-2 Reanalysis Data Reproduce the Three-Dimensional Evolution Characteristics of a Typical Dust Process in East Asia? A Case Study of the Dust Event in May 2017

2020 ◽  
Vol 12 (6) ◽  
pp. 902 ◽  
Author(s):  
Wenrui Yao ◽  
Huizheng Che ◽  
Ke Gui ◽  
Yaqiang Wang ◽  
Xiaoye Zhang
Keyword(s):  
East Asia ◽  
Dust Emission ◽  
Three Dimensional ◽  
Vertical Motion ◽  
Source Area ◽  
Northwest China ◽  
Storm Event ◽  
Dust Event ◽  
Long Distance ◽  
Reanalysis Dataset

This study used the MERRA-2 reanalysis dataset and ground-based and satellite observational data to comprehensively analyze a typical dust storm event in east Asia on 2–7 May 2017 which engulfed most of China as well as ocean and Japan, and explore the accuracy and comprehensiveness of the MERRA-2 dataset in the analysis of dust processes. The results of comparison show that the description of the spatiotemporal distribution and evolution of the dust aerosols in the dust event using the MERRA-2 data is consistent with the data of AERONET, National Urban Air Quality Real-time Publishing Platform and Hamawari-8. Gobi Deserts was the most influential source area of this dust event with the highest emissions reaching 1.9 × 106 μg/m3. The vertical motion of the atmosphere can lift dust from the source area above 500 hPa. There were low-pressure troughs at 500 and 850 hPa and the winds behind and in front of the trough led to the high-altitude, long-distance transport of dust. Dust gradually affected the northwest China, north China, northeast China, and even the ocean and Japan on 2–7 May. This study demonstrates that although there is some uncertainty about the source of dust emission in the MERRA-2 model, the data accurately simulated the evolution of the dust event and analyze it comprehensively, while the accuracy of simulating the long-term evolution of dust requires further evaluation.

Space Weather Effects on Proton Flux Variations in the South Atlantic Anomaly: A Numerical Study performed by Test Particle Simulations

2020 ◽  
Author(s):  
Kirolosse Girgis ◽  
Tohru Hada ◽  
Shuichi Matsukiyo
Keyword(s):  
Geomagnetic Storm ◽  
Space Weather ◽  
Test Particle ◽  
Three Dimensional ◽  
South Atlantic ◽  
Proton Flux ◽  
Storm Event ◽  
Time Varying ◽  
The South ◽  
South Atlantic Anomaly

<p>In this study, we assess the hourly variations of the three-dimensional proton flux distribution inside the South Atlantic Anomaly (SAA) during a geomagnetic storm. We have developed a relativistic three-dimensional guiding center test particle simulation code in order to compute the proton trajectories in a time-varying magnetic field background provided by Tsyganenko model TS05 and the corresponding time-varying inductive electric field. The Dst index is the main input parameter to the simulation model, while the maximum proton flux, the area of the SAA calculated below a selected threshold, and the penetration depth of the protons are the main output variables investigated in this study were. Since the LEO spacecraft and human-related activities are already affected by space weather conditions, the South Atlantic Anomaly (SAA) is also believed to create an additional source of risk. As the radiation environment depends essentially on the particle flux, the objective of this study is to estimate quantitatively the proton flux variations inside the South Atlantic Anomaly (SAA) in quiet and in storm conditions. So far, it was found that after several drift periods, the protons in the South Atlantic Anomaly (SAA) could penetrate to lower altitudes during geomagnetic storm event, and that, the SAA maximum flux value and the corresponding area, varied differently with respect to altitudes. Numerical results were compared with observations by NOAA 17 and RD3R2 instrument mounted on International Space Station (ISS).</p>

scholarly journals NUMERICAL SIMULATION OF WAVE-DRIVEN FLOWS ON A MORPHOLOGICALLY EVOLVING BEACH

2020 ◽  
pp. 56
Author(s):  
Ramy Marmoush ◽  
Ryan Mulligan
Keyword(s):  
Numerical Simulation ◽  
Wave Field ◽  
Numerical Models ◽  
Field Studies ◽  
Wave Transformation ◽  
Wave Flow ◽  
Nearshore Zone ◽  
Beach Morphology ◽  
Morphology Change ◽  
Beach Sediments

Wave-driven flows in the nearshore zone are responsible for the erosion and transport of beach sediments, causing a continuous cycle of bathymetric change that is linked with changes to wave transformation and nearshore hydrodynamics. Numerical models have been used to investigate the evolving nearshore wave field corresponding to beach morphology change in field studies (e.g., Ruiz de Alegria-Arzaburu et al., 2013). In the present study, the non-hydrostatic wave-flow SWASH model (Zijlema et al., 2011) is applied to five laboratory cases to investigate the change in wave and flow fields corresponding to evolving beach morphology during a simulated storm event.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/LZQQuuiqsPY

scholarly journals QUANTIFICATION OF SHORELINE RHYTHMICITY

1984 ◽  
Vol 1 (19) ◽  
pp. 145
Author(s):  
Holly C. Garrow
Keyword(s):  
Multivariate Analysis ◽  
Survey Data ◽  
Three Dimensional ◽  
Eof Analysis ◽  
Shoreline Position ◽  
Dune Erosion ◽  
Beach Morphology ◽  
Topographic Data ◽  
Alternative Approach ◽  
Beach Survey

The study of beach morphology, for example, its changes with wave and tide conditions, is facilitated by the development of simple numerical values which characterize the morphology. Multivariate (EOF) analysis of topographic contour data is a means for determining important morphologic components which vary independently. If these components correspond to familiar shoreline features the researcher considers important, then the development of each component can be quantified by its significance, or weighting, in each sample. Alternatively, the components may be complicated and not useful in quantifying beach morphology. A study of these morphologic components, however, can provide insights into the dynamics of the beach system. If multivariate analysis produces complicated components, an alternative approach, of subjectively identifying shoreline characteristics of interest, can be taken. The characteristics may be the same as those frequently used in past studies, such as beach slope or sand volume. It is likely, though, that EOF analysis of topographic data will suggest more sophisticated characteristics which should be used. Some of these, for example, mean shoreline position or amplitude of a rhythmic shoreline, may be easily quantified, whereas, others such as longshore position of rhythmic features or cusp width relative to embayment width, may be more difficult to quantify. Both of these analysis approaches were applied to beach survey data obtained over a period of ten months (including the El Nifto winter of 1982/83) on Siletz Spit, Oregon. The shoreline was rhythmic with an 800-850 m wavelength throughout the duration of the study. Rhythmic topography has been associated with significant past beach and dune erosion at this site. Hence, it is of interest to describe the beach morphology quantitatively, and relate three dimensional beach changes to wave and tide conditions.

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