ADCP Application for Ocean Current Measurement in the Port of San Diego

1. Where is the San Diego Port?

The San Diego Port is located along the southwestern coast of the United States, in San Diego, California. The port faces the Pacific Ocean and is a leading maritime gateway into Southern California. Its strategic location near major shipping lanes that connect the Americas with Asia and the rest of the world makes it a significant port for trade, tourism, and naval operations.

Port Scale and Throughput

The San Diego Port is a medium-to-large-sized port with diverse facilities. The port has a number of berths, which can accommodate large container ships, cruise ships, and naval vessels. The throughput of the porters is remarkably huge annually and consists of several types of cargo. It is a leading participant in the import and export trades of consumer products, electronics, and agricultural commodities. Additionally, it acts as the main hub in the import of the cruise industry, hosting enormous amounts of cruise ships and passengers on a yearly basis.

Routes and Business

The port possesses an immense network of routes. It has direct connections to main Asian ports like Shanghai in China and Tokyo in Japan, creating opportunities for international trade. Also, there are shipping lines operating to the US and Canadian West Coasts regularly. San Diego Port is also a stop over for cruise liners plying voyages to and from the Caribbean, Mexico and Alaska. This includes general cargo handling related to business activities, container trans - shipment, and cruise ship operations. Then, there is also a great presence of naval facilities at this port, which adds to the economic and strategic importance of the port.

Port Management and Operation

The port, governed by the San Diego Port Authority, functions based on principles such as safety, efficiency, and care for the environment. The management is in charge of the infrastructure within the port, which comprises berths, quays, and storage facilities. They implement international shipping regulations, standards of safety, and environmental protection. The port authority works in conjunction with shipping companies, cruise lines, and other stakeholders to facilitate smooth operations and enhance the competitiveness of the port.

Port Facilities

San Diego Port features state-of-the-art facilities handling several cargo varieties and vessel types. Further, the port contains a container-handling crane that loads the containers on and discharges them from the ships with ease. Cruise vessels have state-of-the-art passenger terminals with embarkation and disembarkation facilities. The port further contains storage areas, which include general cargo warehouses and bulk commodity open-air yards. Besides that, it has facilities for the repair and maintenance of ships, serving both commercial and naval vessels.

Waterways and Direct Navigation

The waterways to the San Diego Port are well-maintained and regularly dredged to ensure vessels can pass through the area in safety. The channel is well-marked within the port, and there are navigational aids such as buoys and lighthouses guiding the ships in their approach. It has direct access to the Pacific Ocean, whereby vessels can easily connect to the global shipping network.

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

Navigation Safety

Accurate knowledge of ocean currents in San Diego Port is of utmost importance for ensuring navigation safety. The current patterns of the Pacific Ocean, driven by factors such as the California Current, tides, and wind, might have a tremendous impact on the movement of vessels. These currents can be used to stipulate the speed and course of ships, particularly in berthing, unberthing, and navigation within channels. Measuring ocean currents would thus enable ship captains to take decisive actions by adjusting their courses accordingly to evade oncoming collisions or groundings.

Optimization of Port Operations

Ocean current information is essential for the optimization of operations. In the berthing of vessels, the direction and strength of the current have to be considered. A strong current can complicate berthing and make the process longer. With precise current measurements, the port operator can identify the most favorable times for vessel maneuvers, perform work scheduling and resource allocation more effective, therefore raising the efficiency of cargo-handling operations. Currents also impact the movement of port-related equipment, such as tugboats and floating cranes, and understanding these factors can enhance operational safety and productivity.

Environmental Protection

Currents are crucially important to the environmental protection concerns in the port area. The currents are most relevant in connection with the problem of pollutant dispersion. Knowledge of currents, following an oil or chemical spill, for example, will go a long way in predicting contaminant spread with a high degree of accuracy, enabling environmental managers to take the necessary preventative and clean-up measures to protect the sensitive marine ecosystem of the Pacific Ocean and the surrounding shores.

The Acoustic Doppler Current Profiler (ADCP) has become a reliable and effective instrument in measuring the currents of the ocean at the San Diego Port with highly accurate and up-to-date information.

3. How do Doppler principle ADCPs work?

Measurement Principle

The principle behind the operation of ADCPs is the Doppler effect. When an ADCP current meter sends a beam of an acoustic signal, the sound wave meets the different particles suspended within the water that is at variance with its original transmitted wave frequency. So, the variation in frequency as measured by this ADCP on return is proportional to the local velocity of all the particles making up the received pulse volume, known as the Doppler shift:. Thus, by using the Doppler equation, the instrument calculates the water current velocity in different layers inside the water column.

Application of Specific Methods in Port Current Measurement

• Ship-borne ADCP: A ship-borne ADCP is installed on a moving vessel. While the ship navigates through the water in San Diego Port, for example, the ADCP measures the current velocity at several depths along the ship's track. This method serves to obtain a broad-scale view of the current conditions in the port, useful for large-scale navigation planning.
• Fixed ADCP: Fixed ADCPs are installed in fixed positions in the port, e.g., on the seabed or on fixed structures such as piers or buoys. These ADCPs can continuously monitor the current condition over a long period from a particular point and thus deliver valuable data on the long-term trends and local variations of the currents.

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

Equipment Reliability

In the San Diego Port, to obtain high-quality current measurement, ADCP current profiler equipment should be extremely reliable. Its marine environment within the Pacific Ocean with high salinity, highly variable weather conditions, and potentially being exposed to strong winds demand that the ADCP profiler is durable enough to withhold these conditions with as little breakdown as possible. Reliable equipment will be able to maintain consistent data collection, important for accurate analysis and decision-making.

Size, Weight, and Power Consumption

Compactness in size, light weight-the ADCP needs to be very easy to install, especially under conditions of strict space limitations that may arise at the time of installation, like on small locally available vessels and in restricted spaces of port structure. Low power consumption is likewise important to effect long-term functioning, especially of fixed-install ADCPs, since they are those that are powered by batteries and solar systems.

Economicalness

The ADCP flow meter should be of reasonable cost to make large-scale measurement in the port area. An inexpensive ADCP will enable the deployment of many units if needed to obtain comprehensive current data from different parts of the port.

Material Selection

The casing of ADCP meter is made of titanium alloy material. Titanium alloy offers great resistance to corrosion. It is suitable for long-time use in saltwater in the Pacific Ocean and is also strong yet light with both durability and ease of installment requirements.

5. How to Select Appropriate Equipment for Current Measurement?

As Per Usage Criteria

• Ship-borne ADCP: It is best for large-scale surveys of the port area. Where a ship needs to make an assessment of the current conditions over a wide range as quickly as possible, a ship-borne ADCP should be used.
• Sit-on-bottom ADCP: It is suitable for long-term monitoring of specific locations in the port, such as near the entrance or close to berths.
• Buoy-mounted ADCP: Useful for acquiring data at the water surface and when fixed - bottom installation is not possible.

Based on Frequency

• Water depth up to 70m, the ADCP frequency is 600kHz.
• ADCP of frequency 300kHz will serve the purpose for 110m water depth.
• For deeper water areas, 75kHz ADCP is the one.

There are several well-known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, for those seeking a cost-effective and high-quality option, the Chinese brand China Sonar PandaADCP is highly recommended. It is made of all-titanium alloy material, ensuring excellent durability in the marine environment, and offers an incredible cost-performance ratio. You can see them in more detail on the site: https://china-sonar.com/.

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