An experimental study on monitoring wave profiles with LiDAR

Abstract

Light Detection and Ranging (LiDAR) has become increasingly popular for on-site wave monitoring due to its high temporal and spatial resolution. However, its potential application in the laboratory has not been well studied. In this study, a LiDAR and seven wave probes were used in a wave flume with a slope, to study the ability of LiDAR monitoring wave profiles in the laboratory. The results show good agreement between the time series of free surface measured by the LiDAR and wave probes, with an average error of less than 4%. Effective sampling ratio (the ratio of the number of LiDAR signals received per second to the sampling frequency at a point), relative wave height, positions of the breaker point and incident wave height are the key factors affecting LiDAR measurement error. When the value of effective sampling ratio is less than 0.8, it has dominant influence on the error. In shallow water, relative wave height is the dominant factor. A negative linear correlation is found between the measurement error and the incident wave height. These findings provide important guidance for processing and assessment of LiDAR data.