The Role of Sea State to the Morphological Changes of Prasonisi Tombolo, Rhodes Island, Greece

Abstract

Wave-induced morphodynamic processes that cause formation, preservation, and destruction of the Prasonisi tombolo in Rhodes Island are investigated, based on satellite image analysis and numerical modeling. A new method is developed for extracting wave events that consist of successive wave data of similar characteristics. The wave events refer either to wind seas or swell seas. This process combined with the satellite image analysis is then utilized for the derivation of the most representative wave scenarios that affect tombolo and salient formation. In particular, the main factors that play a significant role in tombolo and salient evolution are the offshore wave conditions, the location and width of the surf zone, the maximum value of the wave breaking index in the study area, and the initial bottom bathymetry before the study area is exposed to a new sea state. In general, the proposed method provides a realistic insight into tombolo morphodynamics and can be used to provide a cost-effective approach and a wave data-reduction technique for coastal engineering studies.

A Chronology-Based Wave Input Reduction Technique for Simulations of Long-Term Coastal Morphological Changes: An Application to the Beach of Mastichari, Kos Island, Greece

“…As mentioned above, the wave input reduction method [22] uses the wind and wave chronology, extracting the time series of the wind-wave events and swell events from the wind and wave datasets. Specifically, this method results in a time series of events of different wave intensities and durations.…”

“…In the method developed in [22], each swell and wind-wave event is represented by a characteristic wave condition. Referring now to linear data, such as the wave height and wave period, the representative wave characteristics of each wind-wave and swell event are the arithmetic mean values of the corresponding consecutive wave data, as follows:…”

“…More recently, Malliouri et al [22] developed a wave input reduction method that extracts sequences of wind-wave events and swell events from wind and wave time series. Their method is capable of extracting the time series of events of different durations and wave intensities.…”

“…Thus, it can accelerate the process of estimation of long-term coastal morphodynamics by reducing the events' duration through the use of a MORFAC. In addition, their method [22] can assess the sea bottom and shoreline evolution as a time function via process-based morphodynamic models.…”

“…The methodology proposed by Malliouri et al [22] needs waves, but it also needs the wind time series of the same period to extract a sequence of wind-wave and swell events, which implies a limitation regarding the properties of the source data that can be used. Except for this, it would be an advantage if the wave events could be derived from wave time series only since the main objective of the present paper, as well as of a variety of research and coastal engineering studies (e.g., [1,3,4,21]), is to estimate the wave-induced coastal morphodynamics.…”