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Description
SIMshore proposes a prototype service for operational update of the littoral topo-bathymetry making use of remote sensing of the ocean surface. Particular emphasis is assigned to bathymetry derivation from the ocean colour, as well as from inversion of the surface wave field observed at low altitude with aerial autonomous vehiclesSIMShore is clearly user-driven, resulting from many requests of users for littoral bathymetry.SIMOcean aims at developing a pre-commercial operational service with data and algorithms derived contribution of all partners (and other stakeholders to be attracted to the consortium), and elaborate value-added downstream products of wide economic application. The SIMShore project will start with a preliminary preparatory phase of two months, where the project''s assumptions will be consolidated both from the business (Task 5.1 Business Assessment and Requirements) and technical (Task 5.2 Use Cases Definition) viewpoints.The project will then proceed in three sequential cycles consisting of successive stages of A) development, B) testing; C) data collection; D) validation (in ATI4); and E) testing of operations (in ATI5), including business aspects.Each of these cycles will gradually evolve in the hardware platform and payload will (ATI2), algorithms for geo-referencing, bathymetry extraction, data processors and system (ATI3).
Summary of project results
Every winter, storm events cause dramatic modifications in the littoral area. Frequently, a late winter (or early spring) storm can cause greater damage than what was caused since end of summer. In addition to the storm intensity, an explanation may be found on the successive modifications undergone by the sea bottom since the onset of autumn. The submerged beach tends to get deeper and the bottom slope close to the dry area tends to get steeper. The beach, as a whole, loses capacity to dissipate energy and an “off season” storm may easily find the way to aggress the otherwise dry area. Property will be loss, unless we prepare for the storm. To do so, we may track the evolution of the sea-bottom as autumn and winter develop. But acoustically surveying the littoral from a small vessel is virtually impossible, particularly in autumn/winter. Theoretically, it is possible to build a “map” of the sea-bottom in shallow areas within an acceptable uncertainty.
In SIMshore, a camera installed in an Unmanned Airborne Vehicle (UAV), flying in steady mode, collects short time series of wave field images at constant rate. The bathymetry is derived using a wave field inversion technique. The method is limited to waters shallower than 15m, and is only applicable in wave exposed areas. To survey a longshore stretch of coast, a number of overlapping sectors is defined for the flights. After obtaining the bathymetry values and removing the tidal effect on sea level, the data are combined in a seamless way. A time sequence of surveys, say every week or two, will allow tracking the time evolution of the sea-bottom. After computing the rate of change over critical areas, one may decide when to act and what to do.
With a week’s effort of a crew or four, the project delivered the results of two full bathymetric surveys of a complex 1,600m-long beach stretch. By patiently selecting the time opportunity and using a rather limited budget, it is possible to track the evolution of the nearshore bathymetry at short time scales and in a short response time.
Summary of bilateral results
NORCE was, from the very beginning, selected as a potential partner for its solid expertise in UAV operations and all aspects that are connected with it. And its influence on our procedures was striking. But it was far from clear that our response was at the same level.NORCE was rather humble when stating it was interested in our methodology application and suggested an approach to be used in UAV operations that would very much be of its interest. Well, we have failed both. We neither applied our approaches in Norway nor have we attempted to use their suggested approach in our project.There were shared results, though. And we gained from NORCE’s team intervention in the analysis and digestion of the data, but it is not clear that there will be any wider effects, at least not before we conduct a joint overall evaluation, which has not happened. But, of course, there are excellent results at the human level.