The Dynamics of Freshwater Plumes at the Dutch Coast
as observed by high-resolution HF Radar
Presented at the Oceans'98 conference in Nice
Klaus-Werner Gurgel ,
Heinz-Hermann Essen and
University of Hamburg, Institute of Oceanography,
Tropolwitzstrasse 7, D-22529 Hamburg, Germany.
Tel: +49-40-42838-5742, Fax: +49-40-42838-5713,
A full paper has been published in the conference
A High-Frequency (HF)-radar can be used to measure surface current fields
and the spatial distributions of ocean wave directional spectra.
The physical mechanism behind is backscattering from a moving rough surface.
These radars are deployed along the coast and cover an area of up to
50 km * 50 km, which can be observed continuously at 10 minute intervals.
Recent developments at the University of Hamburg within the EU MAST-2
project led to a new HF radar system called
(WEllen RAdar), replacing the
WERA simultanously measures surface currents and ocean waves,
and can be operated at 300 m spatial resolution. The area covered in this
mode is about 35 km * 35 km.
WERA has been used to track fresh water patches travelling along the
Dutch coast, which are originated from the Rhine and Ijssel outflow into
the North Sea. The measurements were conducted at Petten, 25 km south of
the island Texel. The WERA high resolution mode showed much more details
of the plume structure, compared to the maximum 1.2 km resolution of CODAR.
Surface current gradients of up to 50 cm/s within 300 m have been observed.
In future, HF radar will be an important tool for coastal management and
harbour authorities. Integrated systems using both radar measurements and
numerical models are to be developed for this purpose and can play an
important role within GOOS / EuroGOOS.
This work has been funded by the European Commision DG XII within the MAST-2
programme, project SCAWVEX, ct94-0103.
last update 04-Jun-1998