ADCP's Application to Ocean Current Measurement in Tema Port

1. Where is Tema port?

Tema Port is located on the Gulf of Guinea in southeastern Ghana. It is the largest and busiest port in Ghana, playing a crucial role in the country's economic development.

Port Scale and Throughput

It covers a large area with several berths. This port can receive all types of vessels, including small and big cargo ships. In terms of throughput, the port annually deals with a tremendous volume of cargo, including farm produce, minerals such as bauxite and gold, and manufactured goods. Over the years, it has continued to increase its capacity to handle goods in response to the increasing demands of trade for Ghana and other neighboring regions.

Routes and Business

Temple Port serves as a transit-shipping base. It has direct routes with many shipping points in different parts of the globe, covering the European Continent, Asia, and the American continent. In the business realm, the port involves itself with generalized cargo-handling, freighted container operations, and general cargo handling by bulk. Also included are imports and exports of liquid bulks; some of its import and export cargoes have involved petroleum-related commodities.

Port Management and Operations

The port is managed by the Ghana Ports and Harbors Authority. The management focuses on ensuring efficient operations, safety, and security. They implement modern port management systems to streamline the processes of vessel berthing, cargo handling, and documentation. Regular maintenance and upgrades are carried out to keep the port infrastructure in top - notch condition.

Port Facilities

Tema Port is equipped with modern cargo handling equipment, including cranes of various capacities, forklifts, and conveyor belts. There are also large - scale storage facilities, such as warehouses for general cargo and silos for bulk commodities. Additionally, the port has facilities for ship repair and maintenance, which can handle minor to medium - sized repairs.

Channels and Direct Navigation

The port has well - maintained channels. The main channel is deep enough to accommodate large - draft vessels. It has been dredged regularly to ensure smooth navigation. There are also navigational aids, such as buoys and lighthouses, along the channels to guide ships safely in and out of the port.

2. Why should we measure the ocean currents in the Tema port?

Measuring ocean currents in Tema Port is of great significance for several aspects of port operations and management.

Safety of Vessel Navigation

Accurate knowledge of ocean currents helps in ensuring the safety of vessels navigating in and out of the port. Currents can affect a ship's speed, direction, and maneuverability. Strong or unexpected currents can pose a risk of collisions with other vessels, port structures, or cause a ship to run aground. By having real - time or accurate historical current data, ship pilots can better plan their routes and adjust their navigation strategies, especially when approaching or leaving the berths.

Cargo Handling Efficiency

Ocean currents can influence the positioning of vessels during cargo handling. If the currents are not properly accounted for, it may lead to difficulties in aligning the ship with the cargo - handling equipment, such as cranes. This can result in delays in loading and unloading operations. By measuring the currents, port operators can optimize the scheduling of cargo handling activities, reducing the overall turnaround time of vessels and increasing the efficiency of the port.

It's the current from the port areas which play another role in a local marine ecosystem. This usually influences the movement of nutrients and planktons plus other organisms into the water, depending on a variety of causes. Therefore knowing the currents serves for proper environment management for example to predict pollutants when an oil spills occurs, environmental mishap to protect local biodiversity about marine biodiversity in that particular site.

ADCP (Acoustic Doppler Current Profiler) has emerged as a more advanced and convenient method for measuring ocean currents in Tema Port. It offers high - resolution and real - time data, which is crucial for the above - mentioned aspects of port operations.

3. How do ADCPs using the Doppler principle work?

ADCP Measurement Principle

ADCPs operate based on the Doppler principle. When an acoustic wave is emitted from the ADCP profiler transducer and strikes a moving target (such as suspended particles in the water), the frequency of the reflected wave will change. The magnitude of this frequency change, known as the Doppler shift, is proportional to the velocity of the target along the acoustic beam.

ADCPs typically have multiple acoustic beams (usually 3 or 4). By measuring the Doppler shifts of the acoustic waves reflected from different directions, the ADCP flow meter can calculate the three - dimensional velocity components of the water flow. The vertical velocity can be determined from the upward - looking beams, and the horizontal velocities can be calculated from the combination of the angled beams.

Port Current Measurement: Special Techniques

Ship-borne ADCP

Mount the ship-borne ADCP on the hull of a moving ship. In this case, the ADCP current profiler now measures the velocity of the water relative to the ship as the ship moves in the water. The absolute velocity of the water can be derived by accounting for the motion of the ship itself through GPS or other navigation systems. This method is valuable for achieving an overview of the current patterns prevailing in the port area. This method can easily cover a large area and provides information on how the currents differ at different areas of the port.

Fixed ADCP

Fixed ADCPs are mounted on the seabed or on structures at the water side, such as piers or buoys. The fixed ADCPs keep on measuring the current velocity continuously at a single location. Fixed ADCPs are ideal for long - term monitoring of current patterns at critical points in the port, for example, near the entrance channels or berths. They may provide high - frequency data over an extended period of time, useful for studying daily, weekly, or seasonal changes in the currents.

4. What's needed for high-quality measurement of Tema port currents?

Equipment Reliability

For high-quality measurement of currents in Tema Port, the ADCP current meter equipment must be highly reliable. The materials used in the construction of the ADCP should be able to withstand the harsh marine environment, including exposure to saltwater, strong currents, and varying temperatures.

Small Size, Light Weight, and Low Power Consumption

The ADCP should be small in size and light in weight, especially for applications such as fixed - point monitoring or when used on small vessels. This makes it easier to install and maintain. Additionally, low power consumption is essential, especially for long - term deployments where power sources may be limited, such as on buoys or in remote areas of the port.

Low Cost

To enable large-scale measurement of ocean currents in Tema Port, the cost of the ADCP equipment should be low. This allows for the deployment of multiple units to obtain a comprehensive understanding of the current patterns in the port.

Titanium Alloy Casing

The casing of the ADCP is preferably made of titanium alloy. Titanium alloy has several advantages. It is highly corrosion - resistant, which is crucial for long - term use in the saltwater environment of the port. It is also strong, ensuring the protection of the internal components of the ADCP meter. Despite its strength, titanium alloy is relatively lightweight, meeting the requirement of having a light - weight device.

5. How to Select the Suitable Apparatus for Current Measurement?

On the Basis of Application

Ship-borne ADCP

A ship-borne ADCP should be used to get a panoramic view of current patterns in the port area in a relatively short time. Such an ADCP can be rapidly mounted on a vessel and moved across the port, sampling data at various locations around the port.

Bottom-mounted (Sitting - bottom) ADCP

For long-term monitoring of current conditions at a specific location, such as near a berth or in a channel, a bottom - mounted ADCP is more suitable. It can continuously record data over an extended period without the need for constant vessel - based operations.

Buoy-mounted ADCP

Surface-level currents can be monitored with the help of a buoy-mounted ADCPs. These are useful in areas that are inaccessible due to difficult landlocked areas or in case the mobility of a monitoring platform is required. It can also be used in studying the interaction of surface currents with wind.

Based on Water Depth

The choice of ADCP frequency is also related to the water depth. For water depths less than 70m, an ADCP with a frequency of 600kHz is suitable. It provides high-resolution data in shallow waters. For water depths up to 110m, a 300kHz ADCP is more appropriate. When dealing with water depths of up to 1000m, a 75kHz ADCP should be used.

Well, some of the known brands in the market are Teledyne RDI, Nortek, and Sontek. However, if one wants value for money, yet it is of good quality, then the Chinese brand China Sonar PandaADCP is recommended. It is made of all-titanium alloy material; hence it is resistant to corrosion and is quite durable. With its incredible cost-performance ratio, it offers a great option for current measurement in Tema Port. You can visit their website at (https://china-sonar.com/) for more information.

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