ADCP's Application to Ocean Current Measurement in the Port of Lázaro Cárdenas

1. Where is Lázaro Cárdenas port?

Lázaro Cárdenas is a Mexican port on the Pacific coast of the state of Michoacán. This is an important and very fast-growing port, having a strategic position in the country's maritime infrastructure.

Port Scale and Throughput

It boasts of its extensive scale and stands in the ranking of one of the major freight carriers in Mexico. Huge quantities are handled through the port, inclusive of bulky shipment: enormous volumes of containers, filled with manufactured goods literally ranging from all types along with bulk commodities such as iron ore, coal, grains, and oil. It acts as an important link in the international trade of Mexico, with exports to different destinations in Asia, North America, and Europe, and imports of goods that are basic for the domestic market.

Routes and Business

The port of Lázaro Cárdenas has a well-developed network of shipping routes. It is connected to many other ports around the world, making it easy for trade to flow. The business activities of the port are quite varied. It is very instrumental in the export of Mexican natural resources, including minerals and agricultural products. For example, it exports large amounts of minerals and fruits. Import-wise, it allows the intake of machinery, electronics, and other consumer goods to flow in, which are desperately needed by the local economy and the industries.

Port Management and Operation

It operates on professional management that concentrates on operational efficiency and safety. For control over the movement of vessels, as well as loading and unloading operations, stringent regulation and measures are in place regarding traffic control, and it should observe general principles of safety and security within the port area. To boost its competitiveness and meet bigger volumes of cargo, the regular upgrading and maintenance of the facilities are performed.

Port Facilities

The Port has a number of modern and up-to-date facilities. There is a long quay wall with many berths in the ports capable of accommodating huge container ships, bulk carriers, and oil tankers. There are high-class advanced container terminals with high-capacity cranes at the port facility to manage the containers with quickness and accuracy. For bulk cargo, the facilities include separate storage and conveyor systems. Storage and transfer facilities of liquid cargo such as large oil storage tanks and pipelines also exist. Support services include ship repair yards, fueling stations, and areas where provisions can be supplied to the vessels.

Channel and Navigation

The channel is deep and wide, the dredging regularly undertaken to admit large vessels through it. It has a complete set of navigational aids like buoys, lights, and radar systems to assist in smooth and efficient navigation by ships into and out of the port. This ensures that navigation may be direct and smooth even under different conditions of weather and tide.

2. Why is it necessary to measure the currents in the Lázaro Cárdenas ocean port?

Improved Vessel Navigation

Ocean current measurement in the Lázaro Cárdenas ocean port plays a vital role in vessel navigation. Currents in the Pacific Ocean may have an enormous impact on the speed, route, and fuel consumption of a ship. Current information allows ship captains to make the best use of favorable currents for minimizing time and fuel. For example, this allows entering or leaving the port on proper current direction and strength so as not to result in any collisions or grounding.

Infrastructure Protection

Ocean currents around a port are always interacting with the quay walls, berths, and other submerged structures. Over time, heavy or unpredictable currents may result in erosion, scouring, and other structural damages. Current measurements often help the port authorities identify the areas that are liable and undertake timely preventive measures, such as reinforcement of structures or adjustment in dredging schedules, to safeguard the integrity of the port and extend the life of its facilities.

Marine Environmental Management

Understanding ocean currents is important in the management of the marine environment in the port area. Currents are considered one of the major agents for the dispersion of pollutants, sediments, and heat. In the case of monitoring the currents, appropriate measures may be taken to control the spread of any potential contaminants, sedimentation management, and protection of the aquatic ecosystem. This is necessary for the healthy maintenance of the marine environment and to maintain the requirements of environmental legislation.

Acoustic Doppler Current Profiler (ADCP) is more advanced and convenient in measurement than traditional methods of ocean currents. It can provide comprehensive, even real-time information in speed and direction at different depths of currents within the port to assist decision-making for better performance in both port operations and environmental protection.

3. How do the Doppler Principle ADCPs work?

ADCPs work on the principle of the Doppler effect. Transducers installed on the instrument emit acoustic signals into the water. These acoustic waves interact with the particles carried by the ocean currents-suspended sediments, plankton, and other small entities in the water column.

The acoustic waves emitted and falling on the moving particles, due to the Doppler effect, bounce back with a changed frequency. A change in frequency is measured by the ADCP meter. With some sophisticated algorithms, it calculates the velocity of the moving particles based on the frequency shift. This information about velocity gets further translated into the speed and direction of the ocean currents.

Two major ways of ADCP deployment are in practice regarding Lázaro Cárdenas port:

Ship-borne ADCP

A ship-borne ADCP is installed on a vessel that could be a survey ship, cargo ship, or any specialized research vessel. The ADCP current meter will continuously emit and receive acoustic signals while the ship moves around the port area and its adjacent waters. Coupling the vessel's own motion data to the current measurements from the ADCP profiler provides a complete view of the ocean current patterns in different parts of the port and surroundings.

Fixed ADCP

Fixed ADCPs are installed at strategic points in the port-in the seabed near the entrance or along the quay walls, or at other points critical to the navigation channel. They remain in one position, constantly measuring the current conditions around their particular location. Long-term information from fixed ADCPs is quite essential for understanding the normal pattern of flow, any abnormal changes, and trends for port planning and safety.

4. What is needed for measurement of high-quality currents in the port of Lázaro Cárdenas?

Quality and Durable Materials

In view of such an aggressive marine environment, for quality measurements of ocean currents at the port of Lázaro Cárdenas, equipment needs to be made out of materials resistant to the impacts it will undergo. Seawater is corrosive; pressure changes could be considerable depending on the depth to which equipment is subjected. For quality and repetitive measurements, it requires material that would not be subject to corrosion or degradation and thus would allow its structural integrity to be preserved for extended periods.

Compact Size and Light Weight

Size and weight are also important considerations for the equipment. In a very busy and usually space-limited working environment in the port, a compact-sized ADCP is more practical for installation, whether on a ship or at a fixed location. A lightweight design is also very helpful, especially for ship-borne ADCPs, since this reduces the impact on the vessel's stability and handling during operation.

Low Power Consumption

The low power consumption is important mainly when considering fixed ADCPs that have to operate continuously. Beyond the obvious operating cost savings, low power consumption simplifies the power supply requirements and improves the long-term reliability of the equipment.

Titanium Alloy Casing

It is very highly recommended that the casing of the ADCP flow meter be made of a titanium alloy. Titanium alloy is highly resistant to corrosion and hence quite befitting in the marine environment. This material also possesses a very high strength-to-weight ratio that will allow a sturdy yet relatively lightweight design. In this way, the ADCP can resist such pressure and impacts it may incur in port waters without losing performance and accuracy.

5. Selection of Equipment for Current Measurement?

According to the Usage Scenarios

Ship-borne ADCP: When the purpose is to carry out detailed current pattern surveys in a large area of the port and its immediate surroundings, a ship-borne ADCP will be more suitable. It may be applied for periodic checks of the port area, for new infrastructure planning, or during the evaluation of current effects on vessel traffic.

Bottom-mounted (sit-on-bottom) ADCP: Long-term and stable monitoring of current conditions at specific critical locations within the port, such as the entrance, areas near important berths, or underwater structures, requires a bottom-mounted ADCP. It provides continuous data that is necessary to understand the regular flow and sudden changes that may affect port safety or operations.

Buoy-mounted ADCP: If it is more relevant for the measuring point to be flexible or even mobile-like for acquiring current data in different positions according to particular requirements, or in places hard to access in another way, then one should consider using a buoy-mounted ADCP.

Frequency Selection

A good starting point for waters up to 70 m depth is the 600kHz ADCP.

For depths up to 110m, a more suitable ADCP is one with 300kHz.

In deeper waters up to 1000m, a 75kHz ADCP can give precise measurements.

There are some well-known ADCP brands, like Teledyne RDI, Nortek, and Sontek. However, here it is necessary to mention one Chinese brand: China Sonar PandaADCP. It is made of titanium alloy material, and it is durable, ensuring excellent performance in the marine environment. Moreover, its cost-performance ratio is outstanding. You can find more information on its website: (https://china-sonar.com/).

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