ADCP applied in Ocean current measurement in the port of Singapore

1. Location of the Port of Singapore

The location is strategic, actually the southern point of Malay Peninsula, connected to the confluence of Malacca Strait, into South China Sea and served for most critical international seas from Europe through African Middle East via Pacific Asia. The scale of port and its throughput The Port of Singapore is one of the largest and busiest in the world. An intensive network of terminals-which encompasses container terminals, bulk terminals, and specialized terminals for several cargo types-drives it to remarkable figures per year in annual throughput. Centrally placed among the top-ranked worldwide ports, each year it is entrusted to handle millions of containers in terms of twenty-foot equivalent units, or just simply TEUs. It also handles a great deal of bulk cargo, such as oil, gas, and minerals. Actually, the port is ever-changing with continuous expansion and modernization projects, which have greatly increased its capacity due to growing demands in the field of international trade.

Routes and Business

There is a huge network of shipping routes that the port utilizes. It is also a transshipment hub, and ships from all over the world call into Singapore to transfer cargo. The Port of Singapore undertakes a wide range of business activities. Other than core shipping and cargo handling, there is an industry related to ship repairing and maintenance which has a very vibrant industry. In addition, it serves as the center for marine services, logistics, ship-chandling, and marine insurance. The fact that many foreign shipping companies and maritime-related companies are represented in Singapore further emphasizes its importance to international maritime economic activities.

Port Management and Operations

The port is managed by the Maritime and Port Authority of Singapore, better known as MPA. MPA is responsible for overall planning, development, and regulation of the port. It ensures efficient functioning of port facilities, vessel traffic management, and enforcement of safety and environmental regulations. The MPA also promotes Singapore as a premier maritime center through initiatives such as investing in advanced technologies, collaborating with international partners, and developing a skilled maritime workforce.

Facilities

The port of Singapore is a facility with modern infrastructure. The container terminals are highly automated, with advanced gantry cranes and container-handling systems that can operate with high precision and speed. There are large-scale storage yards for containers, equipped with modern inventory management systems. In the case of bulk cargo, there are dedicated terminals with specialized handling equipment, such as pipelines for liquid bulk and conveyor belts for dry bulk. The port has extensive ship-repair facilities, including dry docks, floating docks, and workshops capable of handling vessels of various sizes and types.

Channels and Direct Navigation

Approaches to Singapore Port are in good depths, with drafts allowing large draft vessels. It is regularly surveyed and dredged as and when the need arises. Navigational aids to ensure safe navigation include lighthouses, buoys, and sophisticated radar systems, particularly in the congested waters off the port area. From the open sea, vessels can go directly to the port via well-marked shipping lanes. Because of the heavy volume of traffic, there are stringent procedures regarding the management of traffic to make certain that vessels move in an orderly and safe manner.

2. Why should we measure the ocean currents in the Singapore Port?

Measurement of the ocean currents at the Singapore Port has served several aspects with regards to its operation and management.

Navigation Safety

Given the heavy traffic in the Port of Singapore, knowledge about the ocean currents has a critical use: navigating safety. Currents can act on course, speed, and stopping distance of ships. A cross-current of appropriate magnitude would badly affect the on-course situation of the vessel either while berthing or through the narrow channels in order to keep the risk of collision with other vessels, port structures, and the shore within tolerable limits. These estimations will, therefore, enable captains to make correct decisions, adopt modified ways of navigation, and exercise caution to avert the chances of possible accidents.

Optimal Port Operations

Ocean current awareness helps in port operation optimization. While performing berthing or un-berthing operations, the direction and magnitude of the current remain crucial. A favorable current can help in easily handling the vessels without much labor involvement, which saves a lot of time and energy. However, on the contrary, unexpected or strong current results in delays and difficulties. In addition, the stability of the ship is determined by the current during loading and unloading. With current, real-time data, port operators can schedule this much better; it would definitely ensure that this operation happens during conditions as per their favor to again increase overall port productivity.

Environmental Protection

Measurement of ocean currents in the case of an environmental disaster such as a discharge of oil or pollutants also plays a relevant role. Currents will determine the direction and speed at which pollutants will spread. Knowing current patterns, port authorities will also be able to predict quickly the path the pollutants are likely to travel and rapidly mobilize resources to contain and clean up the spill, thus saving the local marine ecosystem and its wide variety of marine life. It protects the coastline from pollution impacts, which would be vital to the tourist industry and good health of the community in the area.

Among all of these techniques, ADCPs are the state-of-the-art and the easiest way to measure sea currents. In this respect, instruments can do continuous estimation at high resolution in both depth and horizontally to achieve inclusiveness of a current structure perspective in the concerned port area.

3. How do the Doppler Principle-based ADCPs function?

Basic Principle of the ADCP Measurements

The function of an ADCP current meter is based on the principle of the Doppler effect. An ADCP sends out acoustic signals to the water column. These signals are scattered by small particles in the water-like plankton, sediment, or even bubbles. When these particles are moving because of the current in the water, then the frequency of the scattered acoustic signal received by the ADCP is different from the emitted signal frequency. This frequency shift, commonly referred to as the 'Doppler shift', is directly dependent upon the velocity of the particles, hence that of water current. Provided the Doppler shift is measured accurately, an ADCP would be in a position to calculate the current speed of water as well as the direction at the whole column of water.

ADCP in Port Current Measurement-Application of Specific Methods

• Ship-borne ADCP: A ship-borne ADCP is mounted on a moving ship. While the ship is sailing in the port area, the ADCP current profiler continuously measures the current. This method allows for rapid coverage of large areas of the port and hence provides a broad-scale view of the current patterns. However, the ship's own motion needs to be carefully compensated for in the data processing. Generally, this is done by deploying additional sensors, namely gyroscopes and GPS that precisely calculate the vessel's movement and subtract its effect from the measured current data.
• Fixed ADCP: A fixed ADCP is deployed at a particular place in the port-for example, on a pier or on a buoy or submerged platform. With this configuration, the current is continuously measured during long time series at one point. It is good for the study of long-term trends and variations in the current, aside from giving real-time data to the port operations around the installation area. Fixed ADCPs may be powered by electricity taken from the port's grid, solar panels, or batteries.

4. What's needed for high-quality measurement of Singapore Port currents?

Equipment Reliability

The ADCP flow meter equipment has to be highly reliable to provide high-quality current measurements in Singapore Port. The marine environmental conditions of the port, comprising saltwater, high humidity, and strong winds, demand that the ADCP be able to withstand such conditions. The construction materials used, especially for the casing, will be very important in achieving reliability.

Size, Weight, and Power Consumption

The ADCP meter shall be compact to allow installation in various places in the port.

Light of weight is an advantage, especially for ship-borne applications. This is because it does not affect the stability of the ship as much.

Low power consumption is also important, especially for fixed-mounted ADCPs, which may be required to operate for long periods of time on alternative power sources, such as solar panels or batteries. This ensures that the ADCP can operate continuously without often changing batteries or power outages.

Cost-effectiveness

The cost of the equipment should be reasonable to allow large-scale deployment in Singapore Port to enable comprehensive current measurement. It means several sets could be installed around different parts of the port and provide more information and accurate readings about the pattern of currents. In regard to being cost-effective, maintenance costs must be at a minimum to sustain the apparatus over long periods.

Titanium Alloy for ADCP Casing

The casing of the ADCP profiler is preferably made of titanium alloy.

Titanium alloy offers several advantages in the marine environment. It has excellent corrosion resistance, which is important to resist the corrosive effects of saltwater over long periods. It is also relatively lightweight compared with other corrosion-resistant materials, such as stainless steel, thereby helping to reduce the overall weight of the ADCP. Besides, it has good mechanical strength, which means it can stand up to mechanical stresses such as those arising from water pressure and impacts of waves or debris in ocean current measurement.

5. How to Choose the Right Equipment for Current Measurement?

Based on Usage

• Ship-borne ADCP: It is good to get a large-scale view of the current patterns in the port. This is ideal for initial surveys or for a rapid assessment of current conditions over wide areas of the port. Ship-borne ADCPs are used to get an overall impression of the current variation within a port for route planning and overall traffic management.
• Sit-on-bottom ADCP: This type is well-suited for long-term, fixed-point monitoring of currents. It is useful for studying the long-term trends and variations in the current at a specific location in the port. Sit-on-bottom ADCPs can provide valuable data for understanding how currents change over time, which can be important for port infrastructure planning and environmental monitoring.
• Buoy-mounted ADCP: Buoy-mounted ADCPs are useful for measuring currents in areas where it is difficult to install fixed-point or ship-borne systems. They can be deployed in areas with high water flow, in open - water regions near the port, or in areas where access is limited. They can also be used in such areas to provide buoy-mounted current conditions in real time, which is a very important data for navigation and protection of the environment.

Based on Frequency

• A 600kHz ADCP will be good for water up to 70m. For a Singapore Port, with some areas not very deep, such as near the shores or even berthing areas, this frequency can be used for detailed measurements. With this higher frequency, currents can be measured with higher resolution in these shallow waters. - A 300kHz ADCP is suitable for depths of around 110m. It would be usable over most of the port, apart from some of the deeper sections in the main channels and/or outer berthing areas. This frequency gives an acceptable balance between depth penetration and measurement resolution.
• A 75kHz ADCP is designed for much deeper waters, up to 1000m. Although very deep waters may not normally exist within immediate proximity to Singapore Port, in the need to take current measurements in the adjacent offshore areas or deeper channels connecting to the port, this frequency can be considered.
• A few well-known brands in the market include Teledyne RDI, Nortek, and Sontek. However, for those seeking value for money with high-quality performance, it is highly recommended to use a Chinese brand: China Sonar PandaADCP. It is made of all-titanium alloy, hence very durable in the marine environment.

With such an incomparable cost-performance ratio, it therefore offers a perfect solution for current measurement in Singapore Port. Further details can be requested from their website: (https://china-sonar.com/).

Here is a table with some well known Acoustic Doppler Current Profiler(ADCP) instrument brands and models.