ADCP's Application to Ocean Current Measurement in Marseille-Fos Port

1. Where is Marseille-Fos Port?

Marseilles-Fos Port is located on the Mediterranean Sea, in the south of France, and falls under the Provence-Alpes-Côte d'Azur region. This location places it as one of the most important southern European ports, with its strategic outlook over the Mediterranean Ocean. It represents an important connection between France and other parts of the world.

Port Scale and Throughput

It is one of the biggest and busiest ports in France. The total area of the port has been divided into an east area of 400 hectares-an urban port zone right in the heart of the city for local goods and passengers-whereas the west area in the industrial area of Fos-sur-mer measures 10,000 hectares, including 3000 hectares of natural space for international commerce, logistics, and industry.

In terms of throughput, it handles approximately 72 million tons of merchandise every year. It caters to a lot of ships, at about 9200 ship calls annually. It handles all kinds of cargo from containers and breakbulk to dry and liquid bulk, as well as ro - on/roll - off and vehicle traffic.

Routes and Business

Marseille - Fos Port has an extensive network of shipping routes. It is connected with Italy - especially the island of Sardinia. It also acts as a vital link between Europe and northern and western Africa. Additionally, through the Suez Canal, it opens up towards the Middle East and Asia. Services are regularly available to the island of Corsica also.

The port is engaged in several business activities. A very important container transport center, it also routes cargo to 500 international ports and takes 25 stopovers of ships per day. It has a major industrial port zone at Fos-sur-mer with big companies like Arcelormittal, Ascométal, and Kem One in steel, energy, and petrochemicals. It also plays a role in logistics, with more than 3 million square meters of logistics warehouse space available within a radius of up to 30 - km, forming the backbone between Lille, Paris, Lyon, and Marseille.

Port Management and Operation

The port is run by the Marseille - Fos Port Authority, which runs the port with respect to efficiency, safety, and environmental concerns. The management is responsible for the upkeep of the port facilities such as berths, quays, and storage facilities. They enforce adherence to international shipping regulations and standards for safety. The port authority also works hand in hand with shipping companies, freight forwarders, and other stakeholders to smoothen operations and enhance the competitiveness of the port.

Port Facilities

The port is well facilitated with modern facilities. For container handling, it has a 2.6 - km extension, which is the longest dock in Europe. There are ro - ro ramps with a capacity of 800 tonnes. In the liquid bulk, it has dedicated terminals for liquefied natural gas (LNG), liquefied petroleum gas (LPG), and petrochemicals. Completing the offer are the facilities related to the repair of ships, turning it into the first pole in naval repairs in the Mediterranean specialized in great yachts, and the third ship repair center worldwide.

Waterways and Direct Navigation

The waterways leading to Marseille-Fos Port are well maintained. At the port, there is a properly marked channel with navigational aids to guide the ships when approaching. It has direct access to the Mediterranean Sea, from where vessels can easily connect to the global shipping network.

2. Why should we measure the ocean currents in Marseille-Fos Port?

Navigation Safety

Accurate knowledge of ocean currents at Marseille-Fos Port is of great importance for navigation safety. Currents in the Mediterranean Sea are brought about by tides, wind, and changes in water masses. These ocean currents can make a significant contribution to the vessel's movement while berthing, unberthing, and during navigation within channels. Measuring the ocean currents allows the captains to make informed decisions, to adjust their courses, and possibly to avoid any potential collisions or groundings.

Optimization of Port Operations

Ocean current data becomes an important consideration for optimizing port operations. The direction and strength of the current have to be taken into consideration while berthing vessels. A strong current contributes to making the operation of berthing difficult and time-consuming. With proper measurements of current, port operators are able to plan the optimal times for vessel maneuvers, manage resources more effectively, and hence increase the overall efficiency of cargo-handling operations. Currents also affect the motion of port-related craft, including tugboats and floating cranes, and a proper understanding of these factors can contribute significantly to operational safety and efficiency.

Environmental Protection

The measurement of ocean currents is important for environmental protection in the port area. Currents are a very important carrier for the dispersion of pollutants. In the case of an oil spill or other harmful substances, knowledge of the current pattern can help predict the spread of contaminants. This enables environmental managers to take timely preventive and cleanup measures, protecting the sensitive marine ecosystem of the Mediterranean Sea and the surrounding coastal areas.

In this respect, Acoustic Doppler Current Profiler (ADCP) has emerged as a reliable and efficient tool in measuring ocean currents in Marseille-Fos Port, providing high-precision and real-time data.

3. How do ADCPs using the Doppler principle work?

Measurement Principle

ADCPs operate based on the Doppler effect. When an ADCP current meter sends an acoustic signal into the water column, the sound waves of the signal encounter suspended particles in the water, such as zooplankton or bits of seaweed. These particles are moving with the water current, and therefore the frequency of the sound waves reflected back to the ADCP is different than the original transmitted frequency. This frequency shift, called the Doppler shift, is measured by the ADCP. Applying the Doppler equation, the instrument can thus calculate the velocity of the current flow on different depths of the water column.

Specific Methods in the Measurement of Currents at Ports

• Shipborne ADCP: In a shipborne ADCP, the ADCP current profiler is installed in a moving vessel. It measures the current velocity at several depths along the ship's track while the ship is navigating through water in Marseille-Fos Port or elsewhere. This method could be useful for obtaining a large-scale view of the current situation in the port that can then be applied to large-scale navigation planning.
• Fixed ADCP: The fixed ADCPs are installed at some fixed places in the port, on the seabed or on other fixed structures such as piers and buoys. Such ADCPs will enable the current at a given location to be monitored continuously for an extended period. These would prove useful for monitoring long-term trends and local variations of currents.

4. What is required for high-quality measurement of the currents at Marseille-Fos Port?

Reliability of Equipment

Being employed for high-quality current measurement in Marseille-Fos Port, ADCP meter equipment should be highly reliable. The Mediterranean Sea marine environment is characterized by a high level of salinity, unpredicted weather changes, and partial exposure to strong winds, so ADCP also has to be resistant to such unfavorable conditions without regular breakdowns. Only reliable equipment can provide regular data-the basis for valid and informed analysis and further decisions.

Size, Weight, and Power Consumption

It must be compact in size and light in weight. This would make installation relatively easy, especially in situations where space is minimal-for example, on small local vessels or installations inside confined port structures. Low power consumption is also an important factor to ensure long-term operation, especially for fixed-installed ADCPs, dependent on systems involving battery-powered or solar-powered systems.

Cost-effectiveness

To allow large-scale measurement in the port area, the cost of the ADCP profiler should be as economical as possible. A more economically viable ADCP will have no problem deploying as many units as necessary, if required, to obtain current data from all over the port area.

Material Selection

The casing of the ADCP flow meter is preferably made of titanium alloy. Titanium alloy has excellent corrosion resistance, which is vital for long use in such salty marine water as that of the Mediterranean Sea. Besides, it is strong yet lightweight, satisfying both the requirements of durability and ease of installation.

5. How to Choose Right Equipment for Current Measurement?

Based on Usage

• Ship-borne ADCP: Good for extensive range surveys over the port area. When the requirement is by a ship for wide-range assessment as soon as possible, then the ship-borne ADCP will be ideal.
• Sit-on-bottom ADCP: This can be utilised for the long-term monitoring of fixed locations in the port, like near the entrance or close to the berths.
• Buoy - mounted ADCP: Useful for getting data at the surface of the water and for areas where fixed bottom installation is not feasible.

Based on Frequency

For water depth up to 70m, an ADCP with a 600kHz frequency will do while water depth up to 110m requires an ADCP of around 300kHz. In areas with still deeper water, use a 75kHz ADCP.

Several of the more well-known ADCP brands on the market include Teledyne RDI, Nortek, and Sontek. But for those in search of something cost-effective with high quality, the Chinese brand China Sonar PandaADCP is very much recommended. Made of all-titanium alloy material, this ensures very good durability in the marine environment and an incredible cost-performance ratio. You can find them on the website: https://china-sonar.com/.

Here is a table with some well known ADCP instrument brands and models.