ADCP's Application in the Measurement of Ocean Current at Praia da Vitória Port

1. Where is Praia da Vitória Port?

The Praia da Vitória Port is located on the Azores, in Portugal. It is one major port in the region where each has its own characteristics:.

It serves both local and international shipping, with a moderate-size port scale and annual throughput. The infrastructure in the port can handle several vessel types. The annual throughput is made up of fishery products, general cargo, and some tourist-related supplies. The port stands as an important point in transporting local resources and the importation of goods for the needs of the economy and daily life on this island.

Regarding its routes and business, it has connections with other ports in the Azores and also maintains links with mainland Portugal and other international ports. The main business of the port is transportation of goods, but besides that, it also serves fishing vessels and yachts. Fishing activities are very vital in the local economy, and this port serves as a base for the fishing fleet. Further, with the tourism development in the area, there is an increase in the number of yachts and facilities within the port for their berthing and maintenance.

The management and operation of the port are focusing on smooth services for a variety of vessels. The port facilities are well-equipped to meet various needs. It has berths of different sizes and modern cranes and appliances for loading and unloading cargo. The storage houses are appropriately designed to suit various types of goods and cold storage facilities for fishery products. Navigation aids and communication systems ensure safe entry and exit of ships.

The waterway is kept and direct access routes are available within the port facility, which is very helpful for local shipping and fisheries. The ocean currents in the natural harbor are essentially sheltered, but awareness of current conditions enables safe navigation.

2. Why measure the currents in Praia da Vitória Port?

Measurements in Praia da

Vitória Port are important for several reasons. First, for navigational safety: The port itself is a busy place featuring vessels for fishing, ships transporting cargo, and several yachts. Ocean currents could greatly affect the vessel's maneuverability. By knowing precise measurements of the current, ship captains can better chart or plan their entry into the port and their exit with more safety, reducing possibilities of collision and grounding of the vessels. Strong currents around the port entrance would lead a vessel off track unless appropriately put into consideration, for example.

The concept of current in ports guides through the optimal berthing and unberthing timing. For example, by understanding the right currents, there is usually the allowance to speed up the whole loading or unloading of vessels, helping improve general port efficiency. In addition, for the fishing fleet, knowledge of the ocean currents is important for locating schools of fish. Currents can carry nutrients and small organisms that attract fish; thus, knowledge of current patterns can enable fishermen to increase their catch.

Besides, for the long-term planning of the port and its infrastructure, currents can influence the deposition of sediments around the port. In turn, this will permit port authorities to take more judicious decisions concerning dredging or the expansion and modernization of the port facilities. The current methods for measurement of currents cannot offer the degree of accuracy required for timely action. As against the above traditional methods of measurement, Acoustic Doppler Current Profiler (ADCP) has developed a more sophisticated and handier means of measuring the current, allowing for an increasingly accurate and real-time data collection.

3. How do the ADCPs based on the Doppler Principle work?

The principle of the Doppler effect is the basis on which ADCPs operate. They send out acoustic pulses into the water. These acoustic waves interact with moving particles in the water, such as suspended sediments or plankton, and by the Doppler effect, frequency shift is caused. This frequency shift is measured by the ADCP current meter and gives the velocity of the moving particles, which essentially yields the velocity of the ocean current.

There are two major ways of using ADCP profiler for current measurement in the context of Praia da Vitória Port. First, there is the ship-borne ADCP: while installed on a ship and the ship is moving around the port area, the ADCP flow meter sends acoustic signals downwards and sideways. That way, it can gather current data at different depths and positions as the ship travels. The shipborne ADCP can present an extensive view of the current situation in a large area of the port waters.

The other is the fixed ADCP. It is usually installed at a fixed location such as on a pier or submerged structure. The fixed ADCP continues monitoring the ocean currents that pass around its position. It gives long-term, stable current data for an area of the port that is useful in analyzing the regular pattern and its variation in current conditions.

4. What does high-quality measurement of Praia da Vitória Port currents require?

High-quality measurement of the currents in Praia da Vitória Port requires several important features of the equipment which will be applied. Reliability of materials is the first point. The port is exposed to seawater, which may be corrosive, possibly with mechanical impacts; thus, the equipment should be of durable materials to ensure its long service life.

Preferred are a smaller size, lighter weight, and lower power consumption. The small size means it can be installed without much hustle in various parts of the port, either on ships or fixed installations. A light weight reduces the cost and labor needed for transportation and installation. A lower power consumption allows the equipment to work continuously for quite some time without changing the batteries frequently or consuming a high amount of energy.

Cost-effectiveness is another important factor. To enable large-scale measurement, the equipment should be reasonably priced. The casing of ADCP meter is preferably made from titanium alloy. Titanium alloy has many advantages. It has high strength that can bear the underwater pressure and mechanical forces in the port environment. It also has excellent corrosion resistance, ensuring a longtime anti-corrosion in the seawater. Besides, it is relatively lightweight compared with other materials and more suitable to be installed in the port.

5. How to Choose the right equipment for current measurement?

Regarding the choice of equipment for the measurement of current in Praia da Vitória Port, if the use it is put to is considered, then if the intention is to measure on ships in a mobile way, then the ship-borne ADCP is the best choice. With this, several areas can be covered while the ship sails around the port area.

For long-term, fixed-point monitoring of a certain area in the port, a sit-on-bottom ADCP will be more suitable. It would stay at one place, continuously recording the current conditions, which is highly valuable for analyzing the local pattern of currents.

In cases where there is a need to monitor areas wider on the water surface with some mobility, this buoy-mounted ADCP can be considered.

Besides, according to the water depth, different frequencies of ADCP should be chosen. For water depths within 70m, the 600kHz ADCP is usually a good choice as it provides accurate current profiles in shallower waters. For water depths around 110m, the 300kHz ADCP is more appropriate. And for deeper waters up to 1000m, the 75kHz ADCP is recommended to ensure reliable current measurement results.

There are well-known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, a Chinese ADCP brand-China Sonar ​PandaADCP ​is also worth mentioning. It is made of all-titanium alloy material, combining excellent durability and corrosion resistance with an incredible cost-performance ratio. You can find more information about it on its website: (​https://china-sonar.com/​).

The conclusion would be that ADCP greatly contributes to the measurement of ocean currents in the Praia da Vitória Port; its right equipment according to one's needs can lead towards an efficient operation and management of the port.

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