Experimental study on the wave measurements of wave buoys

Wave measurement is of vital importance for assessing the wave power resources and for developing wave energy devices, especially for the wave energy production and the survivability of the wave energy device. Wave buoys are one of the most popular measuring technologies developed and used for long-term wave measurements. In order to figure out whether the wave characteristics can be recorded by using the wave buoys accurately, an experimental study was carried out on the performance of three wave buoy models, viz two WaveScan buoys and one ODAS buoy, in a wave tank using the European FP7 MARINET facilities. This paper presents the test results in both time and frequency domains and the comparison between the wave buoys and wave gauge measurements. The analysis results reveal that for both regular and irregular waves, the WaveScan buoys have better performances than the ODAS buoy in terms of accuracy and the WaveScan buoys measurements have a very good correlation with those from the wave gauges.

Assessing the utility of geospatial technologies to investigate environmental change within lake systems

Over 50% of the world's population live within 3. km of rivers and lakes highlighting the on-going importance of freshwater resources to human health and societal well-being. Whilst covering c. 3.5% of the Earth's non-glaciated land mass, trends in the environmental quality of the world's standing waters (natural lakes and reservoirs) are poorly understood, at least in comparison with rivers, and so evaluation of their current condition and sensitivity to change are global priorities. Here it is argued that a geospatial approach harnessing existing global datasets, along with new generation remote sensing products, offers the basis to characterise trajectories of change in lake properties e.g., water quality, physical structure, hydrological regime and ecological behaviour. This approach furthermore provides the evidence base to understand the relative importance of climatic forcing and/or changing catchment processes, e.g. land cover and soil moisture data, which coupled with climate data provide the basis to model regional water balance and runoff estimates over time. Using examples derived primarily from the Danube Basin but also other parts of the World, we demonstrate the power of the approach and its utility to assess the sensitivity of lake systems to environmental change, and hence better manage these key resources in the future.