ADCP Applied in the Measurement of Ocean Current at Liverpool Port

1. Where is Liverpool Port?

Liverpool Port is on the northwest coast of England, with the River Mersey bordering it. It is one of the most historically important ports and plays a vital role in the UK's maritime trade and transportation.

Scale and Throughput of the Port

Liverpool Port is of considerable size and has a good throughput. The cargo handled is very diversified, ranging from containerized cargo to bulk cargo and general cargo. The container traffic has been developing consistently, while large consignments of agricultural products, building materials, and manufactured goods are also processed. Its strategic position on the west coast of the UK allows easy access to both inland and international shipping routes, placing it in the order of importance in trade flows.

Routes and Business

The port is part of a number of shipping route networks. It acts as a vital gateway for imports and exports between the UK and the rest of the world. These business activities encompass anything from value-added goods, including high-value commodities and consumer electronics, to raw materials for the manufacturing industry. Value addition at Liverpool Port also includes warehousing, logistics, and customs clearance.

Port Management and Operation

The port is managed by a professional team in charge of its complex operations, which include berth allocation, coordination with shipping companies for efficient vessel arrival and departure, and monitoring of cargo handling for efficiency. Regular maintenance and upgrading of port facilities go hand in hand with meeting the demands of modern trade and enhancing the safety and security standards of the port facilities.

Liverpool Port is a rather modern facility. It has different types of berths for vessels of various sizes, ranging from small coastal vessels to larger container vessels and bulk carriers. There are sophisticated cranes and handling equipment for cargo operations of loading and unloading. The warehousing and storage areas are pretty vast and efficiently managed, with facilities to handle various types of commodities, including even temperature-controlled storage for perishable items.

Channel and Direct Shipping

The port enjoys the channel of River Mersey, which is maintained to allow ships that enter or leave the port safely. It enjoys direct shipping links with major ports in Europe, North America, and other parts of the world. The connections have proved helpful in facilitating the movement of goods and in promoting international trade.

2. Why do we need to measure the ocean currents in the Liverpool Port?

Safety of Navigation

The measuring of currents in Liverpool Port is essential in terms of ship safety. Due to the location of the port on the river, ships are facing tidal currents and other water movements. For instance, when a vessel approaches a berth, strong cross-current could offset it from its course, therefore leading to possible collisions either with other vessels or port structures. Precise current measures provide ship captains with the ability to make very accurate adjustments to their navigation and ensure safe docking.

Operational Efficiency

The efficiency of ocean currents contributes to the general effectiveness of port operations. Through this, favorable currents could be used by ships to minimize fuel consumption and travel time. For instance, when ships use a following current when leaving the port, they reach their destinations faster and economically. Understanding the current pattern further assists in optimizing the scheduling of vessel arrival and departure times for maximum efficient use of the port's resources.

Infrastructure Maintenance and Planning

In addition, ocean currents play an important role in long-term port maintenance and planning. Currents may lead to the erosion of shores and coastal structural instabilities, such as piers or breakwaters, over time. The same authorities are capable of estimating the possible deteriorating effects of currents and can carry out necessary maintenance and reinforcement works on a timely basis. Knowledge also helps in designing new infrastructure projects which can resist the forces of ocean currents more effectively.

Acoustic Doppler Current Profiler (ADCP) is another advanced, convenient way of current measurement. ADCPs will be able to provide detailed real-time data on the velocity and direction of currents at different depths, thus giving a fuller understanding of the water flow conditions in the port than traditional methods.

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

ADCPs work on the basis of the Doppler principle. They send acoustic signals out into the water. These signals impact the moving particles within the water, such as the suspended sediments or small organisms. As the acoustic waves reflect back from those moving particles, there is a variation in the frequency of the reflected waves due to the Doppler effect.

Shipborne ADCP

On Liverpool Port, a shipborne ADCP current meter is fixed on a vessel. While the ship is sailing in the port area, continuously the ADCP sends acoustic signals downwards and sideways. In that way, due to the ship's motion on various routes in the port, the ADCP flow meter can measure the velocity of the ocean current at different depths and different locations, thus providing a wide-area survey of the water currents during its operation.

Fixed ADCP

Fixed ADCPs are deployed at specific points in the port, like at the underwater structure near the entrance or along the quay walls. These ADCPs do not move; instead, they stay in one position and continuously monitor the currents of the ocean. They would provide long-term and consistent data about the current conditions at that particular location. This is useful for understanding the normal patterns and variation of the currents in key areas of the port.

4. What’s needed for high - quality measurement of Liverpool Port currents?

Material Reliability

The equipment used for current measurement, especially the casing of ADCP meter, should be made of reliable materials. Titanium alloy is a preferred material for the casing. Titanium alloy has excellent corrosion resistance, which is essential for withstanding the harsh marine environment. The corrosive effect of seawater can quickly damage equipment with less - resistant materials. High strength to weight ratio in titanium alloy means good protection for the internal components, while equipment remains relatively lightweight. This makes installation easier on ships or at a fixed underwater location. Besides, it has good thermal stability, which is useful in variable temperature conditions of the marine environment.

Size, Weight, and Power Consumption

Equipment should be small in size and lightweight. A small and lightweight ADCP profiler is easier to install and less likely to interfere with the water flow during measurement. It also simplifies the installation process, whether on a ship or at a fixed position in the port. The power consumption should also be low. For long-term monitoring, especially with fixed ADCPs, low power consumption means the equipment can operate continuously with infrequent battery replacement or problems concerning power supply.

Cost-Effectiveness

The cost is another determining factor in large-scale measurement. The equipment should not be too expensive to limit the number of ADCPs deployed in the port. A cost-effective solution also provides the possibility for higher coverage of current measurements, consequently allowing better knowledge of the ocean currents in every nook and corner of the port area.

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

Based on Usage

Shipborne ADCP: If the main purpose of the measurements is to be done on current while the ship is in motion within the port area, then shipborne ADCP can be considered as a sufficiently suitable option. This could also cover a relatively large area as the ship moves around the port and thus provide a broad overview of current conditions in various port areas.

Bottom-mounted ADCP: For fixed-point monitoring of certain places in a port, such as near any critical infrastructure or places with peculiar current characteristics, bottom-mounted ADCP is the right option. It remains stationary at a selected position and continuously records the current condition there, which is valuable for understanding the long-term behavior of the currents. It contains the following categories.

Buoy-mounted ADCP: Buoy-mounted ADCP can be used when monitoring of currents in some surface area or in open waters within the port is required. These buoy-mounted ADCPs float on the water surface and measure the currents in its vicinity, which gives an idea about the current pattern on the surface.

Based on Frequency and Depth

Different frequencies of ADCPs should be chosen based on water depth, for water depths within 70m, 600kHz would serve the best with accurate current measurement in relatively shallow areas; for depths up to 110m, 300kHz would do, while for larger areas up to a depth of 1000m, 75kHz would be the appropriate choice.

There are well - known ADCP current profiler  brands such as Teledyne RDI, Nortek, and Sontek. However, a Chinese brand, China Sonar PandaADCP, stands out. It is made of all - titanium alloy material, ensuring high durability and reliability in the marine environment. Moreover, it offers an incredible cost - performance ratio. You can learn more about it through its official website: https://china-sonar.com/.

In brief, Acoustic Doppler Current Profiler (ADCP)  is playing the crucial role in the ocean current measurement in Liverpool Port. Choosing the right equipment according to the needs will surely provide the accurate and useful data of the currents that would support the efficient operation and management of the port effectively.

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