scholarly journals Long-Term Observations of Beach Variability at Hasaki, Japan

2020 ◽  
Vol 8 (11) ◽  
pp. 871
Author(s):  
Masayuki Banno ◽  
Satoshi Nakamura ◽  
Taichi Kosako ◽  
Yasuyuki Nakagawa ◽  
Shin-ichi Yanagishima ◽  
...  
Keyword(s):  
Morphological Change ◽  
High Frequency ◽  
Climate Changes ◽  
Wave Climate ◽  
Time Interval ◽  
Observation Data ◽  
Beach Profile ◽  
Water Level Variations ◽  
Monthly Variations

Long-term beach observation data for several decades are essential to validate beach morphodynamic models that are used to predict coastal responses to sea-level rise and wave climate changes. At the Hasaki coast, Japan, the beach profile has been measured for 34 years at a daily to weekly time interval. This beach morphological dataset is one of the longest and most high-frequency measurements of the beach morphological change worldwide. The profile data, with more than 6800 records, reflect short- to long-term beach morphological change, showing coastal dune development, foreshore morphological change and longshore bar movement. We investigated the temporal beach variability from the decadal and monthly variations in elevation. Extremely high waves and tidal anomalies from an extratropical cyclone caused a significant change in the long-term bar behavior and foreshore slope. The berm and bar variability were also affected by seasonal wave and water level variations. The variabilities identified here from the long-term observations contribute to our understanding of various coastal phenomena.

Analysis of Wave Climate around Korea Based on Long-Term Hindcast and Coastal Observation Data

2016 ◽  
Vol 75 (sp1) ◽  
pp. 735-739 ◽  
Author(s):  
Weon-Mu Jeong ◽  
Sang-Ho Oh ◽  
Ho Sik Eum
Keyword(s):  
Wave Climate ◽  
Observation Data

scholarly journals Mapping mean and variance of runoff in a river basin

2006 ◽  
Vol 3 (2) ◽  
pp. 299-333 ◽  
Author(s):  
L. Gottschalk ◽  
I. Krasovskaia ◽  
E. Leblois ◽  
E. Sauquet
Keyword(s):  
River Runoff ◽  
Drainage Basin ◽  
Focal Point ◽  
Mean Value ◽  
Order Moment ◽  
Time Interval ◽  
Observation Data ◽  
First Order ◽  
Time Space

Abstract. The study presents an approach to depict the two first order moments of runoff as a function of area (and thus on a map). The focal point is the mapping of the statistical properties of runoff q=q(A,D) in space (area A) and time (time interval D). The problem is divided into two steps. Firstly the first order moment (the long term mean value) is analysed and mapped applying an interpolation procedure for river runoff. In a second step a simple random model for the river runoff process is proposed for the instantaneous point runoff normalised with respect to the long term mean. From this model theoretical expressions for the time-space variance-covariance of the inflow to the river network are developed, which then is used to predict how the second order moment vary along rivers from headwaters to the mouth. The observation data are handled in the frame of a hydrological information system HydroDem, which allows displaying the results either in the form of area dependence of moments along the river branches to the basin outlet or as a map of the variation of the moments across the basin space. The findings are demonstrated on the example of the Moselle drainage basin (French part).

scholarly journals Mapping mean and variance of runoff in a river basin

2006 ◽  
Vol 10 (4) ◽  
pp. 469-484 ◽  
Author(s):  
L. Gottschalk ◽  
I. Krasovskaia ◽  
E. Leblois ◽  
E. Sauquet
Keyword(s):  
River Runoff ◽  
Drainage Basin ◽  
Order Moment ◽  
Time Interval ◽  
Observation Data ◽  
First Order ◽  
Time Space ◽  
Interpolation Procedure ◽  
Instantaneous Point

Abstract. The study presents an approach to represent the two first order moments of temporal runoff variability as a function of catchment area and aggregation time interval, and to map them in space. The problem is divided into two steps. First, the first order moment (the long term value) is analysed and mapped applying an interpolation procedure for river runoff. In a second step a simple random model for the river runoff process is proposed for the instantaneous point runoff normalised with respect to the long term mean. From this model analytical expressions for the time-space variance-covariance of the inflow to the river network are developed, which then is used to predict how the second order moment varies along rivers from headwaters to the mouth. The observation data are handled by a hydrological information system, which allows to display the results either in the form of area dependence of moments along the river branches to the basin outlet or as a map of the variation of the moments across the basin. The findings are demonstrated by the example of the Moselle drainage basin (French part).

scholarly journals Analysis of Long-Term Shoreline Observations in the Vicinity of Coastal Structures: A Case Study of South Bali Beaches

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3527
Author(s):  
Ria Rista Rahmawati ◽  
Anthony Harlly Sasono Putro ◽  
Jung Lyul Lee
Keyword(s):  
Sediment Transport ◽  
Parabolic Type ◽  
Coastal Sediments ◽  
Observation Data ◽  
Coastal Structures ◽  
Beach Profile ◽  
Littoral Drift ◽  
The North ◽  
The Right

Recently, many rigid structures have been installed to cope with and efficiently manage coastal erosion. However, the changes in the coastline or isocenter and the movements of coastal sediment are poorly understood. This study examined the equilibrium shoreline and isocenter lines by applying a Model of Estimating Equilibrium Parabolic-type Shoreline (MeEPASoL) as an equilibrium shoreline prediction model. In addition, the inverse method was used to estimate littoral drift sediment transport from long-term beach profile observations. The movement of coastal sediments was analyzed using long-term beach profile observation data for three Indonesian beaches, namely, Kuta Beach for 13 years, Karang Beach in Sanur for 15 years, and Samuh Beach in Nusa Dua for 18 years. The littoral drift at every site was dynamically controlled by seasonal changes in the monsoon, the erosion and deposition patterns coupled with the presence of coastal structures, and limited sediment movement. Shoreline deformation in Kuta is generally backward deformed, with a littoral drift from south to north. In Sanur, the littoral drift vector carries sediment from the right and left sides and forms a salient behind the offshore breakwater. The littoral drift at Nusa Dua is dominantly from south to north, but the force of sediment transport decreases near the breakwater towards the north. Furthermore, the methods applied herein could aid the development of strategic coastal management plans to control erosion in subcells of coastal areas.

scholarly journals SEA-LEVEL EFFECT ON ANNUAL CYCLIC BEACH MORPHOLOGY IN SWASH ZONE AT HASAKI COAST

2018 ◽  
pp. 35
Author(s):  
Masayuki Banno ◽  
Yoshiaki Kuriyama
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Observation Data ◽  
Swash Zone ◽  
Beach Profile ◽  
Beach Morphology ◽  
Bruun Rule ◽  
Decadal Scale ◽  
And Sea Level

depend on the accurate knowledge of the beach response to sea level regime on multi-time scale. For the long-term beach response, Bruun (1962) suggested that the equilibrium beach profile would move to new equilibrium profile in response to a rising sea level. In this concept called as Bruun rule, the upper part of the beach profile is eroded due to the sea level rise, resulting in the shoreline retreat. It is widely used for the future shoreline prediction. However, the Bruun rule predicts just only the final beach state with a constant wave impinging for an infinite period after sea level rise. On the other hand, simultaneous function of wave and sea level is more important on interannual to decadal-scale beach response. El niño in 2015 and 2016 increased wave energy and sea level, corresponding to large beach erosion across the US west coast (Barnard et al., 2017). Sea level influences the response sensitivity to the wave forcing as a subordinate factor on the morphological change. High water level anomalies made the beach more eroded even if the wave condition was equal. Beach morphology in the swash zone often changes on a 1-year cycle due to seasonal wave conditions. The effect of sea level on the annual cyclic beach morphology in swash zone is still unclear because long-term beach observation data required for the analysis are difficult to obtain. In this study, we investigated the simultaneous effects of the wave and sea level on annual cyclic beach morphology in the swash zone with spectrum analysis for 25-year Hasaki beach observation data.

scholarly journals Littoral drift analysis based on long-term observation of mesotidal beach profile in Kuta Beach, Bali for coastal retreat assessment

2021 ◽  
Vol 925 (1) ◽  
pp. 012040
Author(s):  
R. R. Rahmawati ◽  
A. H.S. Putro ◽  
J.L. Lee
Keyword(s):  
Temporal Variability ◽  
Shoreline Change ◽  
Transport Processes ◽  
Beach Erosion ◽  
Observation Data ◽  
Beach Profile ◽  
Littoral Drift ◽  
Shoreline Changes ◽  
Coastal Retreat

Abstract The beach profile survey in the intertidal zone is crucial for a temporal variability study of shoreline and beach profile change for coastal management. The combination of numerical modelling and field data has proven to be successful in identifying the primary hydrodynamic and sediment transport processes such as littoral and cross-shore drift. Those parameters are relevant to the sandbar migration process and shoreline changes. The purpose of the present study is to analyse the littoral drift that caused temporal variability shoreline change in mesotidal beach for coastal retreat mitigation. Beach profile data of Kuta Beach was analyzed by 7 years of long-term field observation data both east monsoon and west monsoon situation. The shoreline definition used mean sea level (MSL)1.3 m and high water level (HWL) 2.6 m as reference. By using the MeEPASoL program as a graphical user interface program, shoreline changes converging to an equilibrium state can be simulated by taking into account the existing breakwater. Temporal shoreline position resulting from littoral drift and beach width change from its initial position is estimated for coastal erosion analysis. The result showed that dominantly, the littoral drift pattern moved from south to north. Furthermore, this study can be used in the process of identifying the primary hydrodynamic analysis in erosion disaster management as assessment of the beach erosion.

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