ADCP's Application to Ocean Current Measurement in Port of Tacoma

1. Where is the Port of Tacoma?

The Port of Tacoma is situated in Tacoma, Washington, on the Puget Sound in the United States.

Port Scale and Throughput The Port of Tacoma is a major seaport with a high volume of cargo throughput. It is known to handle a wide variety of cargo, from containers and automobiles to bulk commodities like grains and forest products. It handles millions of TEUs of containerized cargo every year and is thus an important part of the supply chain. Its location on the West Coast provides easy access to international trade routes across the Pacific Ocean.

Routes and Business It has extensive connections to major shipping lanes to Asian markets including China, Japan, and South Korea. The importation business at this port comprises consumer goods in the form of electronics, toys, and clothes while American-made products in the form of agricultural produce, machinery, and more are exported. For instance, it is significant in the exportation of grown apples and lumber within Washington state.

Port Management and Operation This port is controlled by a dedicated management team through multiple operations: efficient vessel traffic management, including berthing and departure; the whole handling process concerning cargoes involves sophisticated equipment with professional expertise, apart from proper security to the port area, ships, and merchandise. Shipping lines and terminal operators coordinate with other parties in improving operational aspects for the port authority in giving higher-quality services.

Port Facilities The port is made up of premier facilities. There are deep-water berths capable of hosting large container vessels and other big vessels. Deep-water berths, modern container terminals with fully advanced cranes, and automation handling systems enable fast and efficient loading and unloading of containers. It is also equipped with vast storage of different types like temperature-controlled storage, perishable commodities, and warehouses on a large scale for solid goods.

Channels and Direct Routes The channels at the Port of Tacoma are well dredged and maintained with appropriate depths that enable navigation. It has direct shipping routes to lots of crucial Asian and other key ports that ensure reduced transit times and costs, hence improving competitiveness in the international shipping market.

2. Why is the measurement of ocean currents at the Port of Tacoma a good idea?

Navigation Safety The ocean current measurements are very important to the ships passing through the Port of Tacoma, from the viewpoint of safety. Currents have a big impact on the speed and course of a ship. For example, strong tidal currents in the Puget Sound area make navigation very difficult. Accurate measurement of the speed and direction of the current enables captains to plan routes more accurately and adjust speeds properly, therefore decreasing the chances of collisions and grounding.

Efficient Port Operations The knowledge of ocean currents is of much importance for the efficient handling of cargo. The force of the currents, at the time of docking or undocking, can affect the position of the ships. By understanding the current patterns, port operators can better schedule vessel berthing and allocate resources for cargo handling. This helps in optimizing the use of cranes and other loading-unloading equipment and ensures the smooth flow of goods in and out of the port.

Environmental Protection Ocean current measurement would be quite useful in the case of an accidental discharge of noxious substances like oil or chemicals. The speed and direction of currents will determine how fast and in which direction the pollutants will spread. Having accurate data on currents will, therefore, help emergency response teams to take more appropriate measures in containing and cleaning up the spill to minimize environmental damage.

Compared to traditional techniques, Acoustic Doppler Current Profiler(ADCP) provides a more advanced and convenient way of current measurement. It offers real-time and continuous data across different depths and areas of the port water for a comprehensive understanding of the current situation.

3. How do ADCPs using the Doppler principle work?

The general principle of ADCPs is based on the Doppler effect. An ADCP emits an acoustic signal into the water. These acoustic waves scatter off moving particles in the water, such as sediment, small organisms, or bubbles. When the waves are reflected back to the ADCP, the frequency of the reflected waves has changed by the magnitude of the Doppler shift.

The frequency shift depends directly on the velocity of the moving particles, and thus depends directly on current velocity. The ADCP measures this frequency shift, and so the speed and direction of the current at various levels.

Ship - borne ADCP A ship-borne ADCP is installed on a ship. While the ship is underway, the ADCP sends acoustic pulses downward and laterally and measures the current velocity at several depths relative to the path of the ship. Collected data yields a detailed profile of the current structure in the area covered by the movement of the ship. This is useful in surveying a wide area of the port water as the ship travels.

Fixed ADCP: A fixed ADCP is normally used in installations from piers, buoys, or even at the bottom of the ocean. It gives continuous measurements about the ocean flow that passes through a specific area. In respect to fixed placement, they can give longtime and stable current conditions for just that particular position. This turns out to be very helpful and useful for getting temporal and spatial variations of currents in the area of the port.

4. What is necessary for high - quality measurement of Port of Tacoma currents?

Reliable Equipment Materials The equipment must be of a material that can make the measurement of the current high in quality. That has to withstand the harsh marine conditions: saltwater corrosion, impacts of waves, temperature fluctuations. The casing of the equipment is preferably made from an alloy of titanium. It shall have very good corrosion resistance and is ideal for resisting seawater, which is highly corrosive. Its strength-to-weight ratio shall be excellent; hence, tough yet light enough not to load the device with much weight.

Desirable Equipment Characteristics Small in size and light in weight. The more compact and lighter the device, it becomes easier to install and operate if on a ship or a fixed structure. Low power consumption is also a requisite. This is so that the equipment can run continuously for a long time with no frequent change of batteries or huge power supply.

Cost - effectiveness Cost-effectiveness is an important issue for large-scale measurement in the port area. It has to have a reasonable price for broad deployment. In this way, one can obtain a better picture of the actual situation over various areas in the port.

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

Based on Usage Purpose

Shipborne ADCP: The ship-borne ADCP applies to the requirements when the objective of obtaining currents is during a ship voyage or for the study of issues related to navigation. It can cover a greater part of the port area through movement of the ship itself.

Bottom - mounted ADCP: For long - term and fixed - point monitoring of the currents near the seabed or in areas close to the port's infrastructure, bottom - mounted ADCPs are a good choice. They can provide stable and continuous data about the current conditions at specific locations.

Buoy-mounted ADCP: This is suitable in the areas of open-water currents or on the seabed when installation may be impracticable; buoy-mounted ADCPs that float with wave and tidal movements will monitor these currents in both the deep ocean and river currents.

Based on Frequency Selection The frequencies chosen for any particular ADCP depend on water depth. For example, the 600 kHz ADCP shall be applied in water to about 70 m depth when high-resolution data are needed, while the 300 kHz ADCP provides acceptable performance at up to around 110 m depth, representing an optimal balance between measurement range and resolution. A 75 kHz ADCP is more suitable for deeper waters, up to about 1000 meters, and useful in understanding the current conditions in the deeper parts of the port area.

There are well - known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, there is also a Chinese brand, China Sonar PandaADCP, which is worth considering. It is made of all - titanium alloy material, providing excellent durability and has an impressive cost - performance ratio. You can find more information about it on their website: (https://china-sonar.com/).

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