(Englisch) HF Radar WERA provides valuable met-ocean data

(Englisch) HF Radar WERA provides valuable met-ocean data

The port of Rotterdam in the Netherlands is Europe’s largest sea port. With its outstanding accessibility to the world, it annually connects around 30.000 sea-going vessels with more than 100.000 inland vessels and thousands of trucks and trains with the help of 180 000 people working in and for Rotterdam’s port and industrial area. The sixth biggest port in the world stretches across a length of about 42 km, covering an area of approximately 124 km2. To maintain and sustain the huge amount of nearly half a billion tons cargo per year from and to Central- and Northern Europe fairways, ship traffic has to be safe and efficient.

WERA Receive Antenna Array at Ouddorp beach

Using modern patrol boats and a high-tech traffic control system, the Harbour Division supervises and controls shipping traffic, day and night. Being an official emergency service, the Harbour Master’s Division together with different aid agencies is in charge of safeguard cohesion, safety of shipping traffic, and monitoring of surrounding areas.

The Port of Rotterdam Authority is an autonomous company with two shareholders, the Municipality of Rotterdam and the Dutch government, established to develop and maintain the port of Rotterdam. In connection with their mission to „continually improve the port of Rotterdam and to make it the safest, most efficient and most sustainable port in the world“ (www.portofrotterdam.com), Rijkswaterstaat, belonging to the Ministry of Infrastructure and Environment, decided in 2014 to improve the quality and reliability of the ocean current forecasting. The forecasting is based on a hydrodynamic model operated by Rijkswaterstaat. At the moment a transition is prepared, in which the operational 2D model will be replaced by a new fully 3D model. The independent advisory organization of Deltares plays a very important role in this transition.

Rijkswaterstaat has chosen HF radar technology as additional real-time data input. The shore-based HF radar system provides reliable data of ocean surface

currents as well as wave height and wave direction over long distances (in this case more than 60 km offshore) with outstanding spatial and temporal resolution for vessel traffic service, search-and-rescue and environmental protection applications. Due to the fact that there are no in-water system components, this technology offers a very good price-to-performance ratio compared to other ocean sensing instruments. It is easy to install and maintain. In contrast to single-point measurements, e. g. using buoys, an HF ocean radar system gives access to high-quality spatial data employing the usefulness of land-based instruments.

WERA ocean radar receive antenna array at the beach of Monster with the port of Rotterdam in the background. The systems are operational since autumn 2015.

Each station consists of one transmit antenna system using less than 30 Watts of transmitted power, twelve receive antenna elements, and the necessary electronic equipment. The operating frequency is 16 MHz providing a range of up to 60 km.

The radar signals, emitted from the transmit antennas, are backscattered by the ocean surface and then measured by the receive antennas. Processing of the measured signals yields the direction and strength of the current. There are four measurement cycles within one hour. The data from both radar stations are combined in order to produce the necessary information.

WERA Transmit Antennas at Ouddorp

The EU tender “HF-Radar system Maasmond” has been awarded to the German company HELZEL Messtechnik GmbH which is supported by the Dutch partner companies OCN and Radac. The contract with Rijkswaterstaat was signed in December 2014. The unique ocean radar system WERA® manufactured by HELZEL delivers high-quality ocean current maps covering hundreds of kilometers offshore and maps of significant wave height/directional wave spectra within 50% of the current mapping coverage. The high- resolution current maps show even sub-mesoscale surface current structures. Various comparisons between surface currents measured by WERA® systems and sub-surface currents measured by acoustic Doppler profilers as well as drifters have shown an excellent correlation. A combination of the real-time WERA® measurements with numerical ocean models offer promising opportunities to improve the accuracy of oil spill drift prediction as well as search-and-rescue operations.

Since October 2015 a pair of WERA® ocean radar stations is monitoring the surface currents (speed and direction) at the entrance of the Port of Rotterdam at Hoek van Holland. This installation is the first permanent one in the Netherlands. Earlier projects with HF radar were carried out in 1988 and 1996.

The coverage area extends beyond Hoek van Holland in the west and northwest directions occupying an overall area of 60 x 40 sq.km. The grid resolution depends on range and the allocated radio bandwidth, but is on average about 1 x 1 sq.km . The radar system also provides met-ocean data for parts of the fairway at Hoek van Holland.

Already now the WERA® system is permanently monitoring the coastal area in front of the harbour entrance and very soon the measurements will be assimilated into the envisaged new 3D ocean current model to improve marine oceanographic prediction.

There are two WERA® radar stations near Rotterdam; one site is at Monster and the other is at Ouddorp.

WERA velocity map (November 25, 2015)

Since October 2015 this data availability request has been fulfilled. The reported data availability for current vectors is more than 98% which is a good example of the high data quality and reliability of more than 100 WERA® systems installed worldwide. For instance, at the French Atlantic coast near Brest, two WERA® systems are operational now for more than 10 years. They monitor extremely dynamic current behaviour and waves in front of the coast of Brittany with a permanent data availability of 98,6% without noteworthy failure in hardware and maintenance.

To be able to guarantee a short reaction time in case of any hardware or software failure, the Dutch companies OCN and Radac take care of maintenance, have a spare- part pool on stock and assure a smooth operation of the systems.

Output of Rijkswaterstaat hydrodynamic Model

This information will be available to the pilots and navigation officers of incoming and outgoing vessels as well as to the public society via websites (www.hfradar.nl and www.waterberichtgeving.rws.nl). Deep draught ships, sailing through the narrow dredged shipping lane consisting of the Euro and Maas channel, towards the port of Rotterdam get the precise ocean current information in time to navigate safely towards their destination.

The radar systems are an integrated part of an improved hydrodynamic operational forecasting system which is currently under development for navigation to the port. The operational forecasting requires the highest availability and accuracy of the radar data. Furthermore, there is a strong focus on the on-line quality control procedures. A high data availability in average has been requested by the customer for two defined areas – area A: 95% and area B: 90%.

Installation and maintenance of the system

The acquired current data from the WERA® radar system is presently compared with other data sources and model results. The analysis shows the level of current complexity in the estuary and how much of that can be observed on the surface. Promising publications with results are expected for presentations during upcoming conferences and workshops soon.

Further information could be found at:

www.hfradar.nl / www.waterberichtgeving.rws.nl / www.helzel.com

Our special thanks to Rijkswaterstaat, OCN and Radac for the successful project cooperation.


HELZEL Messtechnik GmbH • Carl-Benz-Strasse 9 • 24568 Kaltenkirchen • Germany • phone +49 (0)4191 95 20 0 • www.helzel.com