Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.1/2167
Título: Performance of intertidal topography video monitoring of a meso-tidal reflective beach in South Portugal
Autor: Vousdoukas, Michalis Ioannis
Ferreira, P. M.
Almeida, Luis Pedro
Dodet, Guillaume
Psaros, Fotis
Andriolo, Umberto
Taborda, Rui
Silva, Ana Nobre
Ruano, A. E.
Ferreira, Óscar
Palavras-chave: Video monitoring
Coastal morphodynamics
Artificial neural networks
Coastal erosion
Remote sensing
Data: 2011
Citação: Vousdoukas, Michalis Ioannis; Ferreira, Pedro Manuel; Almeida, Luis Pedro; Dodet, Guillaume; Psaros, Fotis; Andriolo, Umberto; Taborda, Rui; Silva, Ana Nobre; Ruano, Antonio; Ferreira, Óscar Manuel. Performance of intertidal topography video monitoring of a meso-tidal reflective beach in South Portugal, Ocean Dynamics, 61, 10, 1521-1540, 2011.
Resumo: This study discusses site-specific system optimization efforts related to the capability of a coastal video station to monitor intertidal topography. The system consists of two video cameras connected to a PC, and is operating at the meso-tidal, reflective Faro Beach (Algarve coast, S. Portugal). Measurements from the period February 4, 2009 to May 30, 2010 are discussed in this study. Shoreline detection was based on the processing of variance images, considering pixel intensity thresholds for feature extraction, provided by a specially trained artificial neural network (ANN). The obtained shoreline data return rate was 83%, with an average horizontal cross-shore root mean square error (RMSE) of 1.06 m. Several empirical parameterizations and ANN models were tested to estimate the elevations of shoreline contours, using wave and tidal data. Using a manually validated shoreline set, the lowest RMSE (0.18 m) for the vertical elevation was obtained using an ANN while empirical parameterizations based on the tidal elevation and wave run-up height resulted in an RMSE of 0.26 m. These errors were reduced to 0.22 m after applying 3-D data filtering and interpolation of the topographic information generated for each tidal cycle. Average beach-face slope tan(β) RMSE were around 0.02. Tests for a 5-month period of fully automated operation applying the ANN model resulted in an optimal, average, vertical elevation RMSE of 0.22 m, obtained using a one tidal cycle time window and a time-varying beach-face slope. The findings indicate that the use of an ANN in such systems has considerable potential, especially for sites where long-term field data allow efficient training.
Peer review: yes
URI: http://hdl.handle.net/10400.1/2167
DOI: http://dx.doi.org/10.1007/s10236-011-0440-5
ISSN: 1616-7341
Aparece nas colecções:FCT2-Artigos (em revistas ou actas indexadas)
CIM2-Artigos (em revistas ou actas indexadas)

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