ADCP's Application to Ocean Current Measurement in Tarifa Port

1. Where is Tarifa Port?

Tarifa Port is the southernmost port of Spain, very close to the Strait of Gibraltar. It is an important port city that has had a long, active maritime history.

Port Scale and Throughput

It has a moderately scaled port in terms of throughput, handles cargo such as fishing products from its vibrant fishing industry, and a little tourist-related traffic since the port is nearby popular beach destinations. The yearly throughput depends on the local economic activities and being a connecting point from the Atlantic into the Mediterranean.

outes and Business

It is an essential stopover for sea routes crossing over the Strait of Gibraltar. The port has activities related to fishing, as several fishing vessels use it as a home port for their fishing activities. It also has a developing business in nautical tourism, including yacht charters and ferry services for tourists.

ort Management and Operation

The port management is mainly concerned with vessel safety, considering strong ocean currents around the area. They are well equipped with qualified staff for handling ships at berth and unberthing, controlling the movement of cargo and passengers. The operation involves maintaining the structure against the harsh marine conditions.

Port Facilities

It has a fishing dock with machinery for fish unloading and treatment; on the nautical tourism side, it has berths for yachts and ferries, with infrastructure like fueling stations and tourist information. Besides that, it has a warehouse to store fishing gear and other supplies.

Channel and Direct Navigation

The port has a channel giving way to the sea. The oceanographic conditions in the area are complicated hence making navigation difficult; however, the port has navigation aids guiding the ships through. The ships can navigate directly to and from the port, although ships should be careful because of proximity to the busy Strait of Gibraltar.

2. Why measure ocean currents in Tarifa port?

It is relevant to measure the ocean currents at Tarifa port for several reasons. First, it concerns the safety of the fishing vessels. Knowledge of the currents enables the fishermen to move out safely and catch their fish in good time. This information allows the fishermen to undertake their journeys at appropriate times, avoiding potentially hazardous situations. Current understanding is important in nautical tourism activities for the operation of yachts and ferries. The masters should know the direction and speed of the current to give the tourists a smooth and safe journey. In port operations, ships could have easier times in both docking and undocking with current data. This would allow for the better deployment of tugboats according to the prevailing current conditions. Current measurements also contribute to the upkeep of the infrastructure within the port. Stronger currents in the area could influence the stability of the docks and other structures in the area. Measurement of the same enables the authorities to take precautionary measures to protect the infrastructures and plan for repairs or reinforcements that may be necessary. Acoustic Doppler Current Profiler(ADCP) offers a more efficient and accurate way of measuring these currents compared to traditional methods.

3. How do Doppler-based ADCPs work?

Doppler is what ADCPs basically rely on for operation. It works by transmitting a beam of acoustic signals in water. Where there are particles inside the water-which may consist of sediments and plankton, among other types of particulates-the signal will be returned and its frequency shifted as a function of the target velocity.

This frequency shift is measured by the ADCP and converted to velocity of the particles, using the Doppler equation, which gives the velocity related to the water current. It can measure the current velocity at different depths, creating a profile of the current throughout the water column.

Ship - borne ADCP A ship-borne ADCP is installed on a vessel. The ADCP continuously emits and receives acoustic pulses while the ship moves around the port area. The data gathered from the movement of the ship shows a wide-range picture of the current patterns across different parts of the port.

Fixed ADCP Fixed ADCPs can be installed on the seabed, for example, alongside the docks or in the channel, in locations selected with regard to the purposes of the current measurement. The ADCPs ensure the continuous long-term measurement of current at a single point in the flow area. They are good for monitoring consistent current patterns that influence the port operations and infrastructure.

4. What's needed for high - quality measurement of Tarifa port currents?

The equipment should be made of reliable materials for high-quality current measurement in Tarifa port. The material should be able to bear the corrosive nature of seawater and the sometimes harsh weather conditions. A small size is an advantage in equipment since it can allow for more flexible installation options, especially in the relatively compact port facilities. It is preferred that the weight of the ADCP is light to ease the installation process and to put minimal load on the installation structures. The power consumption should be low to enable continuous operation, as it may not always be convenient to have a high-power supply available. It should also be cost-effective since a port may need to deploy several units for comprehensive current measurement. The casing of the ADCP is preferably made of titanium alloy. The use of a titanium alloy ensures very good corrosion resistance in the marine environment. It is also hard yet lightweight and hence meets the requirements of being durable and easy to install at the port.

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

Based on Usage Purpose

Ship-borne ADCP: This would serve vessels that have to move around the port area, such as fishing boats, yachts, and ferries. It offers a mobile way of measurement for currents and thus can be quite helpful for general views on the current pattern of the port area by simply following the path of the vessel.

Bottom-mounted ADCP: It suits fixed-point monitoring near the docks, channels, or any other critical infrastructure. It gives a continuous record of the current condition at a particular location and is important for the long-term safety and operation of the port.

Buoy-based ADCP: This can be mounted in locations for which it isn't practical to install fixed bottom or ship-borne ADCPS. It also offers floating possibilities for current measurements and may thus cover areas on the open water of the port.

Based on Frequency

The range of frequency used depends among other things, on the depth of the water. For Tarifa, the 600kHz ADCP suits water depths as shallow as 70 m and can work nearer the shore or inner parts of the port. The 300kHz ADCP will go up to 110 m in water depths and will cover most of the range. In this case, for deeper waters in the port area, the 75kHz ADCP is suitable for water depths up to 1000m and shall also be used in all other areas which can have greater depth, such as approach channels. 

Famous ADCP brands are Teledyne RDI, Nortek, and Sontek, but as mentioned above, there's another great alternative brand: Chinese-Chinese sonar pandaADCP, better known by their acronym-China Sonar. A fully metal-adapted Titanium alloy keeps corrosion so that it shows perfect durability on such performance conditions. All with an advantageous price, taking into mind good cost-efficiency. M: Check out https://china-sonar.com for a comparison.

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