Advances in Video Monitoring of the Beach and Nearshore: The Long-Term Perspective

Abstract

It is widely recognized that video monitoring systems are excellent tools in coastal morphodynamic studies as they can capture, simultaneously, beach morphological changes and the forcing mechanisms. Over the last years this remote sensing technique has experience huge developments related not only to technology advances but also to the success of numerous applications reported by the scientific community. Since the first steps of video monitoring of the coastal zone, made by the Coastal Imaging Laboratory of Oregon University in the 1980s, several years have passed by enabling the existence of long-term imagery records. The existence of extended high-resolution time-series make possible to broaden typical video application studies from short-term studies to annual (or longer) time scales as morphological inter-annual variability of the coastal systems is still largely unknown. This work summarizes recent developments on the use of video systems in the understanding of yearly to decadal beach morphological changes and describes the application of a video system deployed at Nazaré, Portugal. The system, operational since December 2008, allowed a detailed description of the coastal evolution at a pluriannual timescale. Results, which are in agreement with previous works, indicate that system variability depends not only on the forcing characteristics that occur at different time-scales (storm, seasonal and inter-annual) but also on antecedent morphology. The use of video systems arises as an optimal data acquisition method to capture this variability and thus support the fully understanding of beach morphodynamics at these wide range of spatio-temporal scales.