Accurate space-time observation of oceanic extreme waves using stereo wave imaging systems

Abstract

The use of spatially distributed (over a 2D horizontal sea surface region) data is nowadays changing the paradigm of sea wave measurements, which, since the early field and laboratory experiments, mostly have been relying on single-point observational systems (e.g., buoys, wave gauges). Active and passive 2D sensors mounted on oceanographic platforms, ships, airplanes and satellites are now becoming standards in the oceanographic community and industry, for offshore and coastal observations, the spatial scale covered by instruments ranging from centimeters to kilometers.In this context, stereo wave imaging (a passive system based on sequences of digital images) is de facto the new standard for acquisitionsof accurate space-time records of sea surface elevations, over sea regions of thousands of square meters. The resulting 3D wave fields have been used by scholars for the analysis of the multidimensional (space + time) shape of “standard”and “extreme” waves, the latter resulting much more likely when inspected over a spatial region. Moreover, the capability to derive the full 3D spectrum from stereo data is revealing new insights of the actual distribution of the wave energy over frequencies and wavenumbers.This study is aimed at describing the new advances of stereo observation, in the perspective of installing and use it on the Korean Gageocho Ocean Research Station (ORS). Main scope is to observe in 3Dservational systems (e.g., buoys, wave gauges). Active and passive 2D sensors mounted on oceanographic platforms, ships, airplanes and satellites are now becoming standards in the oceanographic community and industry, for offshore and coastal observations, the spatial scale covered by instruments ranging from centimeters to kilometers.In this context, stereo wave imaging (a passive system based on sequences of digital images) is de facto the new standard for acquisitionsof accurate space-time records of sea surface elevations, over sea regions of thousands of square meters. The resulting 3D wave fields have been used by scholars for the analysis of the multidimensional (space + time) shape of “standard”and “extreme” waves, the latter resulting much more likely when inspected over a spatial region. Moreover, the capability to derive the full 3D spectrum from stereo data is revealing new insights of the actual distribution of the wave energy over frequencies and wavenumbers.This study is aimed at describing the new advances of stereo observation, in the perspective of installing and use it on the Korean Gageocho Ocean Research Station (ORS). Main scope is to observe in 3D