ADCP Application in the Ocean Current Measurement of Nagoya Port

1. Where is Nagoya Port?

Nagoya Port is located in the city of Nagoya, Aichi Prefecture, Japan. It is one of the most important ports along Ise Bay and an indispensable part of the sea transport infrastructure in Japan.

Port Scale and Throughput

Nagoya Port is a large-scale port with a large port area. It has a high throughput and handles a wide range of cargo. The port is well noted for its container handling and also deals with bulk cargo like automobiles, machinery, and chemicals. The annual container traffic in terms of TEUs is substantial. It contributes to the domestic and international trade of Japan as well as a significant distribution hub in the area.

Routes and Business

It boasts of an immense network of shipping routes. Major Asian ports it is connected to include those of South Korea, China, and Southeast Asian countries. It also has links to various European and Americas ports through different shipping lines. Major commercial activities involve the importation of raw materials, like steel, petroleum products, and agricultural products. It exports a wide variety of manufactured goods, including automobiles, electronics, and industrial machinery.

Port Management and Operations

The management of Nagoya Port is done by an efficient and professional port authority. It tries to ensure efficiency and safety in all operations. Advanced technologies are extended in use in cargo handling, vessel traffic management, and management of logistics, to name a few areas. Workers are well trained in operations related to loading/unloading of containers and bulk cargo, customs clearance, and administrative jobs, among others.

Port Facilities

It is a modern port with complete facilities. It contains container terminals with high-capacity quay cranes that are capable of dealing with big container ships; automobile terminals with ramps and special equipment for efficient loading and unloading of vehicles; bulk cargo terminals with machinery for handling various bulk lot material types. In addition, the port will have ship-repair facilities, warehouses, and storage yards that allow the goods to flow smoothly.

Channel and Direct Shipping

Nagoya Port is adequately serviced with well-maintained channels that can accommodate a range of vessel types. The depth of the channels is also deep enough to handle deep-draught ships. It offers direct shipping services to most important ports, thereby reducing time and transportation costs and increasing its competitiveness in the global market.

2. Why should we measure the ocean currents in Nagoya Port?

Navigation Safety

Accurate knowledge of ocean currents is important to the safety of ships. Currents will affect the speed and course of a ship. In a busy port like Nagoya, with considerable vessel traffic, an understanding of the pattern of the current enables the pilots to navigate more safely. Strong currents near the entrance of the port or narrow channels create risks of collision or grounding. Measurement of the currents will minimize such risks.

Efficiency of Cargo Handling

The ocean currents can give rise to ships' instability during loading and unloading cargo. Inadequate knowledge about the current conditions makes them ineffective in performing well in cargo handling. For example, incorrect positioning of the ship, because of currents, may hamper the activities related to the loading and unloading of cargo. By measuring currents, port operators can effectively plan operations and hence increase overall efficiency.

Environmental Protection

Currents have an important function in the dispersal of pollutants within the port area. In case of oil spillage or discharge of any dangerous chemical, current will fall and must be acquainted with for the prediction of the spread of pollutants, enabling fast and effective response measures for the protection of marine life and the coast.

In comparison, Acoustic Doppler Current Profiler(ADCP) is a better, advanced, and more convenient means of measuring ocean currents than traditional methods. It gives quite accurate and real-time data, which is helpful and useful for the effective management of Nagoya Port.

3. How do ADCPs applying the Doppler Principle work?

ADCP Measurement Principle

The principle on which ADCP is based is the Doppler Effect. It sends acoustic signals into the water. These signals, while passing through the water, experience a frequency shift when they meet the moving particles in it, such as suspended sediment or small organisms. If the particles are moving towards the ADCP, the frequency of the reflected signal increases; if they are moving away, it decreases. This frequency shift can be measured and used by the ADCP to calculate the velocity of the water in which these particles are suspended.

Specific ADCP Methods in Port Current Measurement

Ship-borne ADCP

A ship-borne ADCP is installed on the hull of a ship. While underway, the ADCP measures the current velocity at various depths below the ship. In this way, a profile of the current is obtained along the track followed by the ship. It serves to map overall current patterns in the port area and the approaches to the port.

Fixed ADCP

Fixed ADCPs are deployed at specific locations within the port, such as near the berths or at a location most critical to the channels. These ADCPs record continuously and obtain the current speed and direction of a single location. They can collect long-term, high-resolution data from a specific area that can give comprehensive insight into the current characteristics at each locality affecting the operations of berthing and unberthing, among others, peculiar to the ports.

4. What is required to get highly accurate measurement for Nagoya Port currents?

Reliability of Equipment

For very reliable current measurement in Nagoya Port, the ADCP equipment has to be very reliable since it would have to face a severe marine environment-high waves, salt water, and even typhoons. The raw materials used for making the ADCP must be of very good quality such that its operation may continue long without frequent breakdowns.

Small in size, light in weight, and low power consumption

A small-sized and light-weight ADCP is desired. It will be easier to mount on ships or at fixed locations. The light weight will also reduce the load on the installation structure. Low power consumption, especially for fixed-mounted ADCPs that may be operating on battery power or limited power sources, is required for continuous operation over extended periods.

Low Cost

In order to allow the widespread deployment of ADCPs in the port for comprehensive current measurement, the cost of the equipment should be relatively low. Only a lower-cost ADCP can make possible the installation of multiple units at different locations, hence providing more detailed and extensive current data.

Titanium Alloy Casing

The casing of the ADCP is preferably made of titanium alloy. The use of a titanium alloy is important because it has excellent corrosion resistance, which is very crucial in withstanding the corrosive effects of seawater in Nagoya Port. Besides, it is lightweight, hence contributing to the overall portability and ease of installation of the ADCP. In addition, titanium alloy is strong and durable, able to withstand the physical stresses and impacts that may occur in the marine environment.

5. How to Select the Correct Equipment for Current Measurement?

Usage

Ship-borne ADCP

If the goal is to plot the general current systems of the whole port area when ships are moving, a ship - borne ADCP would be the ideal device. This would be able to give continuous information as the ship sails through different areas of the port.

Bottom-mounted (Sit-on-bottom) ADCP

When current conditions need to be monitored over a long period at a certain location near the seabed, for example around areas with sediment transport, a bottom - mounted ADCP is used. It can give high resolution current information near the bed.

Buoy-mounted ADCP

An ADCP mounted on a buoy is used when the purpose is to measure current profiles in a more mobile and flexible manner. Since the buoy is free to move with the currents, dynamic current patterns can be realized with an increased resolution for the port area.

Based on Frequency

For waters as deep as 70m, the 600kHz ADCP would work best for high-resolution current measurement. In such depths as up to 110m, the 300kHz ADCP would be a better option. For deeper waters with a depth of up to 1000m, a 75kHz ADCP is more appropriate.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, for a cost-effective option, the Chinese brand China Sonar PandaADCP is recommended. It is made of all-titanium alloy materials and offers an excellent cost-performance ratio. You can visit their website at (https://china-sonar.com/) for more information.

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