ADCP in Ocean Current Measurement of Tarrafal de São Nicolau Port

1. Where is Tarrafal de São Nicolau Port?

Tarrafal de São Nicolau Port is located on the island of São Nicolau, Cape Verde. The port faces the sea and is a crucial connection to the people in the area and other neighboring regions.

Port Scale and Throughput

Scale: The port is small to medium in scale, with a few berths, capable of handling vessels in the range from small to medium, such as fishing boats, local cargo ships, and small tourist vessels. The quay area is well-sized, enabling the operations of loading and unloading, while storage facilities manage the incoming and outgoing cargo.

Throughput: Its annual throughput includes fishery products as fishery is also one of the major economic activities of the area. Again, it handles imports of consumer goods, construction materials, and fuel for local consumers and businesses. Tourism-related traffic and the arrival of tourist-carrying boats contribute to the activity of the port as well.

Routes and Business

Routes: The Tarrafal de São Nicolau Port is connected with regional shipping routes, having links with other Cape Verdean ports, including some international ones in West Africa and Europe. These shipping routes support the import/export activities of the island, as well as the transport of tourists.

Business: The only business in the port involves fishing-related operations, which include landing and processing of fish catches. It also covers cargo-handling services for general goods and fuel. On this site, tourism businesses support docking and embarkation-disembarkation services for tourist boats.

Management and Operation of the Port

Port administration would include a system that governs the entry and exit of ships in and out of the port, berth allocation, and cargo-handling activities. As with its management, they had resource efficiency and safety in their focuses. They adopt rules related to safety for protection against any possible hazards to ships, cargoes, and workers. Similarly, there is environmental protection as part of the management to minimize, if not totally eliminate, the adverse effects of these said activities on the local marine environment.

The facilities involve the listing of safety and security measures, such as emergency handling that includes fire and storm procedures. Security checks at the port allow for goods and people to be safe. Environmental protection measures may involve some forms of waste management and those that will prevent pollution.

Port Facilities

Fishing-related facilities: In view of such importance, the port has fish-unloading docks, cold storages for the conservation of fish catches, and basic premises for primary fishery processing. These facilities support activities that concern the treatment of fishing products, as well as maintaining the quality of fish products.

Cargo-handling Facilities: General cargo and bunkers are handled through cranes and other machinery for loading/unloading. Storage areas of different types of cargo, including construction material and consumer goods.

Touristic Facilities: The port has anchoring facilities for tourist boats, an area for passengers to embark and land. It also contains some minimal services like tourist information centers and small shops.

Channel and Direct Shipping

The channels in the port are left in their natural state to facilitate the easy passing of ships. It offers services of direct shipping with main ports in Cape Verde and some international destinations. These direct connections serve as an added convenience for handling cargo efficiently and in the tourism business.

2. Why should we measure the ocean currents in the Tarrafal de São Nicolau Port?

Measurement of ocean currents at Tarrafal de São Nicolau Port is important for several reasons. First of all, for navigation purposes, current data is required with accuracy, which is quite crucial for safe and effective ship traffic. Currents can have an effect on speed and course deviations in vessels, especially smaller vessels such as fishing boats and tourist vessels. Additional information provided to the ship captains creates better speed and course adjustment capabilities, which, in turn, enables collision avoidance and more efficient procedures regarding docking and undocking.

The currents in their turn can have considerable effects on handling operations. Strong or unstable currents may raise problematic demands for operating handling equipment like cranes with a high degree of accuracy. Measurement of the current situation allows the port to timetable cargo-handling operations and to reduce waiting times for ships, consequently improving efficiency in general.

Lastly, the measurement of ocean currents is important from an environmental monitoring point of view. This would give the direction and speed with which contaminants would spread in case of an oil spill or other such pollutants. This would give necessary preventive and remedial measures by the port in time to protect the marine environment. In this respect, ADCP flow meter is both more sophisticated and practical compared to the traditional means of ocean current measurement, which could be very useful for the operations of Tarrafal de São Nicolau Port.

3. How do ADCPs using the Doppler principle work?

Measurement Principle

The basic principle behind the functioning of Acoustic Doppler Current Profiler (ADCP) is the Doppler principle. If the ADCP sends an acoustic signa

l into the water, then such a signal will be scattered by particles and other substances in the water. Since the water particles are in motion with the current of the ocean, the frequency of the scattered signal received back by the ADCP profiler will be different from the transmitted frequency-a fact explained by the Doppler effect. This frequency shift can be measured to calculate the velocity of the water particles and hence the velocity of the ocean current.

ADCP in Port Ocean Current Measurement: Shipborne ADCP

Shipborne ADCPs are installed on ships. While the ship navigates in the Tarrafal de São Nicolau Port area, the ADCP sends and receives continuous acoustic signals. The ADCP doppler is an instrument that can measure currents at various depths along the axis of travel. The data gathered will serve as a means to conduct analysis of the current status around the area in which the ship is sailing, adding to the valuable information for ship navigation and operations. Such is the case of a fishing boat that can make use of the shipborne ADCP in order to find the best route through the waters of the port.

Fixed ADCP

The usual places where fixed ADCPs are deployed are fixed installations along the Tarrafal de São Nicolau Port, such as on piers or buoys. In turn, the ADCPs are kept there, and the ocean currents at their location are continuously measured. They can provide long-term stable current data that enables the understanding of the overall current patterns and changes in the port area over time. For instance, a bottom-moored ADCP current meter near a cargo-handling area provides detailed information on the currents to assist in optimizing cranes' operation.

4. What are the requirements for quality measurement of Tarrafal de São Nicolau Port currents?

Equipment Requirements

Material Reliability: The equipment should be made from materials of a high reliability factor. They must be resistant to corrosion from seawater, high humidity, and impact that could arise from floating objects. In addition, the equipment to be installed at Tarrafal de São Nicolau Port will always be in seawater and all types of weather conditions, hence requiring reliable materials for long-term performance.

Small in Size and Lightweight with Low Power Consumption: A compact-sized, lightweight ADCP flow meter is beneficial to installation and operation, especially for shipborne ADCPs. Low power consumption will enable it to operate for a long time without the need to replace batteries frequently or high-power supply requirements, which will be of essence in both fixed and shipborne ADCPs. Some other key factors are ease of installation and operational processes, considering the various vessels entering and leaving Tarrafal de São Nicolau Port.

Low Cost for Mass Measurement: To achieve large-scale current measurement in the port, the equipment cost should not be too high to enable multiple ADCPs to be set up at different locations within the port for wider current data coverage. Since the need to cover the different areas of the port will be essential, and therefore highly desirable, equipment cost must be as low as possible.

The Benefit of Using Titanium Alloy for ADCP Casing

Titanium alloy is proved to be a perfect material for ADCP profiler casing. Firstly, it has great resistance to corrosion, which can effectively resist the corrosive effect of seawater. In the context of Tarrafal de São Nicolau Port, it ensures that the stability and reliability of the equipment can be guaranteed in a long term. It has a high strength-to-weight ratio, hence can easily offer a considerable increase in strength without adding much to the total weight. This will meet the small size and low-weight requirements and hence reduce difficulties in installing and operating the ADCP flow meter. Thirdly, the thermal stability of the titanium alloy is good, which can make the equipment work normally in a different temperature environment in the Tarrafal de São Nicolau Port area.

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

According to the Use Purpose

Shipborne ADCP: In either case, if the measurement is applied primarily from ships, then a shipborne ADCP may be suitable. Capable of moving along with the ship and making the measurements from the different areas that the ship navigates across the port; for example, in the Tarrafal de São Nicolau Port, cargo ships and fishing boats may use shipborne ADCPs to grant real-time current information for safe navigation.

Sitting - Bottom ADCP: It is suitable for long-term fixed-point current monitoring at a particular location within the Tarrafal de São Nicolau Port. In general, sitting-bottom ADCPs are mounted on the seabed and can continuously monitor the currents that flow in its surroundings. Sitting-bottom ADCPs can provide stable and long-term current data, while sitting, for example, near the entrance of a port or at critical docking areas.

Buoy - Type ADCP: The buoy-type ADCP is fit for the applications that require current real-time monitoring within a certain area of the port. A buoy is capable of floating on the water surface, with an ADCP flow meter on it to measure the currents around it. In areas like middle of the port or near fishing areas, buoy-type ADCPs can provide useful current information.

Selection Based on Different Frequencies

Different frequencies of ADCPs are suitable for various water depths. For example, 600 kHz ADCP profiler is suitable for water depths within 70 m. It can provide more detailed current data in relatively shallow water areas. In Tarrafal de São Nicolau Port, this would be useful near the shore or in the shallower parts of the port. Although the 300 kHz ADCP flow meter works satisfactorily for water depths up to 110 m, the 75 kHz ADCP profiler can be used much deeper, up to 1000 m. These different frequencies allow the measurement of currents at different depths in Tarrafal de São Nicolau Port according to the real conditions of water depth.

There are several well - known ADCP flow meter brands such as Teledyne RDI, Nortek, and Sontek. However, for those looking for cost - effective options, the Chinese brand China Sonar PandaADCP is highly recommended. It is made of all - titanium alloy material and has an incredible cost-performance ratio. You can visit its website (https://china-sonar.com/) for more information.

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