ADCP's Application to Ocean Current Measurement in Toulon Port

1. Where is Toulon Port?

It is located in the Provence-Alpes-Côte d'Azur region of southern France, along the Mediterranean coastline. As a result of its strategic position on the Gulf of Lions, it offers good access to major shipping lanes crossing the Mediterranean. The location thus turns it into one of France's most important commercial ports, connecting the country to diverse markets worldwide.

Port Scale and Throughput

Toulon Port is a medium-sized port with notable capacity. Several berths characterize it, and each berth accommodates different kinds of vessels: container, cruise, and military vessels berthing facilities arising from its nature of dual usage-as a commercial and naval port. The volume of cargo passing through the port is huge yearly. It deals in the import and export of general cargo, including consumer goods, industrial equipment, and construction material. It also caters to cruise liners, accommodating numerous cruise liners and passengers throughout the year.

Routes and Business

It has an established network of shipping routes. It has links with the main Mediterranean ports, such as Barcelona in Spain, Genoa in Italy, and Tunis in Tunisia. Such routes have ensured the circulation of goods within the region. Toulon Port also serves as a stop-over for cruise ships crossing the Mediterranean. On the business side, it operates general cargo handling, cruise ships, and naval operations. The port is the base of the Mediterranean fleet of the French Navy, which also adds to its economic and strategic importance.

Port Management and Operation

The Toulon Port Authority is the commercial management authority of the port, focusing on operations concerning safety, efficiency, and compliance with the rules. Management of the port includes upkeep of the berth structure, the quays, and storage areas. It enforces international shipping regulations concerning safety and environmental protection. In collaboration with the port authority, shipping companies, cruise lines, and other stakeholders make operational synergies to enhance the port's competitiveness.

Port Facilities

Toulon has modern facilities at the port to handle a wide range of cargo and vessel types. There are cranes for handling containers, which can quickly load and unload the cargo from the ships. Similarly, for cruise ships, it contains passenger terminals with embarkation and disembarkation facilities. Storage areas in the form of warehouses for general cargo or open-air yards for bulk commodities also exist within the port. Plus, it has ship-repair and maintenance facilities, both for commercial and naval vessels.

Channels and Direct Sailing

The waterways leading to Toulon Port are adequately cared for, and dredging is often done to make the ways safe for ships to navigate. There is a well-marked channel inside the port, while buoys and lighthouses add to the navigational aids, guiding every vessel in its approach. Being directly linked with the Mediterranean Sea, vessels can directly link up with the global shipping network.

2. Why measure the currents in Toulon Port?

Navigation Safety

The precise knowledge of the ocean currents within the Toulon Port is needed for the safety of navigation. Current patterns of the Mediterranean Sea-forced tides, wind, and exchange of water masses-may have an important impact on vessel movements. These currents can affect the speed and direction of ships, especially during berthing, unberthing, and navigation within the port's channels. By measuring the ocean currents, ship captains can make informed decisions, adjust their courses, and avoid potential collisions or groundings.

Port Operations Optimization

Ocean current data is crucial for optimizing port operations. When berthing vessels, the direction and strength of the current need to be carefully considered. The strength of a current will increase the difficulty and time of berthing. With reliable data on currents, port authorities will be able to plan optimal vessel maneuvers at better times, therefore better exploitation of resources and efficiency in cargo operations. Currents also affect the motion of port equipment, such as tugs and floating cranes; thus, knowledge about these aspects may provide even better operational safety and productivity.

Environmental Protection

The measurement of ocean currents is important for environmental protection in the port area. Currents are very important in the dispersion of pollutants. In the case of an oil spill or other harmful substances, knowledge of the current patterns can help predict the spread of the 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.

Now, an Acoustic Doppler Current Profiler (ADCP) is a valid and efficient tool in measuring the ocean currents at Toulon Port. Moreover, it has provided real time data with high precision.

3. How do the ADCPs work using the principle of Doppler?

Measurement Principle

The ADCPs are based on the principle of the Doppler effect. When an ADCP flow meter sends an acoustic signal into the water column, the sound waves encounter suspended particles in the water, such as sediment or small organisms. As these particles move with the water current, the frequency of the sound waves reflected back to the ADCP differs from the original transmitted frequency. The ADCP measures this frequency shift, which is called the Doppler shift. With the Doppler equation, the instrument calculates the water current velocity in most depths of the water column.

Methods of Measurement Particular in Currents at the Port

• Ship-borne ADCP: A ship-borne ADCP is installed on a moving vessel. While the ship is sailing through the water in Toulon Port, the ADCP current profiler can measure the current velocity at several depths along the track of the ship. This method is useful for obtaining a broad-scale view of the current conditions in the port, which is beneficial for large-scale navigation planning.
• Fixed ADCP: These are installed in specific locations in the port on the sea floor or mounted on fixed structures like piers or buoys. The ADCPs can, over fairly long periods, monitor the instantaneous current conditions at one point continuously and yield very useful data on the long-term trends and local variations of the currents.

4. What is required for the good measurement of Toulon Port currents?

Reliability of Equipment

Equipment for ADCP will have to be very reliable to yield high-quality current measurement in Toulon Port. With its high salinity, variable weather, and exposition to strong winds, the Mediterranean Sea requires ADCP capable of bearing these conditions without breakdowns. In turn, reliability allows consistent data intake, important for further high-precision analysis and decision-making.

Size, Weight, and Power Consumption

The ADCP current meter should be compact in size and lightweight. This makes it easier to install, especially in situations where space is limited, such as on small local vessels or in confined port structures. The ADCP also needs to be low power consuming to enable its operation over extended periods, particularly for fixed-installed ADCPs that may depend on battery-powered or solar-powered systems.

Cost-effectiveness

The ADCP meter shall be reasonably priced to enable large-scale measurement in the port area. By reasonable pricing, multiple units can be deployed if necessary to get comprehensive current data from different parts of the port.

Material Selection

Preferably, the casing of the ADCP profiler is to be made of Titanium alloy. Titanium alloy features excellent resistance to corrosion-very important for long service in the salty marine Mediterranean Sea. It is strong yet light, fitting for both the demands of durability and ease of installation.

5. How to Choose the Right Equipment for Current Measurement?

Based on Usage

• Ship-borne ADCP: Best suited for extended surveys of the port area. When a vessel needs to quickly assess the current situation over large areas, then a shipborne ADCP would be ideal.
• Sit-on-bottom ADCP: Such a type is suitable for long-term monitoring of selected sites in the port area, for instance, at its entrance or far from berths.
• Buoy-mounted ADCP: Suitable for getting data at the surface of the water and when fixed-bottom installation is not possible.

Based on Frequency

• In water with a depth of up to 70m, one can work with an ADCP frequency of 600kHz.
• For water up to 110m deep, the appropriate ADCP is of 300kHz.
• To study areas with higher water depths than those specified above, a 75kHz is suitable.

There are several well-known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, for those seeking a cost-effective and high-quality option, the Chinese brand China Sonar PandaADCP is highly recommended. It is made of all-titanium alloy material, ensuring excellent durability in the marine environment, and offers an incredible cost-performance ratio. You can also check their website at https://china-sonar.com/.

Here is a table with some well known Acoustic Doppler Current Profiler(ADCP)  instrument brands and models.