Search

The efficiency of beach recovery during a time of moderate waves following storm waves is closely related to the interaction between dynamics, sediment, and the landform. The existing studies mainly focus on the description of erosion and accretion characteristics, while the response and feedback mechanism of beach berm sediment have not been elucidated. The main controlling factors of recovery efficiency are not clear. In this paper, field observation and the XBeach numerical model are utilized on the sandy beach in Puqian Bay, China, to capture high-frequency cross-shore data during the post-storm recovery period. The variation characteristics and rules of berm elements, including berm ridge height and slope on two sides of the berm ridge, are analyzed. It is observed that the berm constantly changes to adapt to dynamic conditions. Additionally, a correlation between volume change and certain landform parameters is proposed, leading to the identification of a new relationship in wave run-up. The new forum reflects berm influence and considers the berm ridge and berm width. [ABSTRACT FROM AUTHOR]

In order to solve problems of traditional image denoising methods such as image blur, edge information loss and so on, an image denoising method based on improved simplified pulse coupled neural network was proposed according to characteristics of underground images including uneven luminosity and large noise. Selection of neurons joining strength β was improved, which made β depend on pixel gray value of image, so as to get better denoising effect. At the same time, selection of decay time constant αE of dynamic threshold was improved, which made αE depend on amplification coefficient vE of threshold output, so as to reduce number of parameters of simplified pulse coupled neural network model. The value of vE was selected through experiment. The experiment results show that the method removes salt and pepper noise of underground images more effectively and preserves details of image edge more completely than traditional median filtering and mean filtering.

Abstract During Hurricane Sandy, wave overtopping occurred along the barrier beach in front of the Rehoboth Bay, one of the Delaware Inland Bays, as indicated by field observations and the morphological profile model CSHORE. CSHORE estimated a total overtopping volume of about 9.7 × 10 7 m 3 which is close to the storm surge-induced water volume entering the bays through the inlet (about 1.3 × 10 8 m 3 ). In this study, we incorporated the wave overtopping result from CSHORE into the nearshore community model, NearCoM-TVD, to investigate the wave overtopping-induced excessive surge (OIS) in the Delaware Inland Bays. With the wave overtopping applied in the flux boundary condition, the model successfully reproduced the high water level measured at the station located in the Rehoboth Bay. Additional numerical experiments for the separate effects of wave forcing and local winds are also carried out. The results show that wave forcing has a minimal effect on the water level inside the bays. The adjustment of local wind forcing does not qualitatively improve the agreement between the model and data. The model with included wave overtopping predicted an excessive surge of about 20 cm in the Rehoboth Bay, agreeing better with the measured data. Finally, the responses of OIS to different overtopping conditions were performed using an idealized model setup. A strong asymmetry, represented by a much longer draining period versus a shorter period of overtopping increase to the OIS peak, was found in the OIS process for a given temporally symmetric time series of overtopping flux. The asymmetric feature is caused by the imbalance between the overtopping flux and the discharge through the inter-connecting channel inside the Inland Bays. Nonlinearity plays an important role in the process of OIS as demonstrated in modeling OIS-tide-surge interaction. Highlights • Modeling of excessive surge induced by wave overtopping in an inlet-bay system. • The wave overtopping-induced water volume is close to the storm surge-induced volume entering the bays through the inlet. • Wave overtopping has a significant influence on storm surge inside the bays. • Nonlinearity plays an important role in the interaction between overtopping-induced surge and tide. [ABSTRACT FROM AUTHOR]