ADCP Application to Ocean Current Measurement in the Port of Kokkola

1. Where is Kokkola Port?

Overview of Kokkola Port

Kokkola Port is on the west coast of Finland. As a major port with substantial scale and throughput, the regional economy heavily relies on its services for various kinds of cargo transport: from forestry products and minerals to general industrial goods.

It is well-connected with the domestic and international shipping route. The management is also efficient in the port to keep up with smooth operation. There are well-organized teams for vessel traffic management, cargo handling, and other port-related functions. Advanced technologies are being adopted to make operations more effective and safe.

Port Facilities

Berths: The port has a number of berths, each built to handle various vessel types. There are berths for medium-sized cargo ships and barges. Modern mooring and docking facilities in these berths ensure the safe arrival and departure of ships. The use of high-quality fenders and bollards helps in withstanding the forces during docking and undocking.

Cargo - handling Equipment: There is a range of cargo - handling equipment along the quay. Cranes and conveyor systems are provided for forestry products such as timber and pulp. For minerals and other bulk cargo, there are grabs and conveyor belts to move materials from the ships to the storage areas. Gantry cranes are used for container handling.

Storage Facilities: There are storage areas for different types of cargo. For forestry products, there are stockpiles with proper protection from the elements. For minerals, there are storage areas with containment systems to prevent spillage. There are also container yards and warehouses for other general cargo.

Channel and Navigation Aids: The channel is dredged at the port to a suitable depth and width to allow ships to pass through safely. Regular dredging operations are undertaken to maintain it for vessels with variable drafts. In addition, buoys, beacons, and radar systems ensure navigation of the ships into and from the port. The radar systems ensure the position and movement in real time of other vessels in the vicinity of the port.

2. Why do we need to measure the ocean currents in Kokkola Port?

Importance for Operation and Management of the Port

Firstly, for ensuring the safety of vessel navigation. It's the knowledge of current speed and direction that's necessary for the captains when approaching the berth or passing through the channel. A strong cross-current near a berth makes the process of docking difficult and dangerous. For example, a ship approaching a berth against a strong current may need to adjust its speed and angle of approach to ensure a smooth and safe docking. Accurate current measurements allow captains to make informed decisions and reduce the risk of collisions and other accidents.

Second, it is crucial for the smooth running of the port facility. Up-to-date information enables better planning of ships' arrival and departure times. By knowing the tidal currents and other cyclic flow, port authorities are able to plan better utilization of berth facilities and schedule loading/unloading activities. This again results in greater productivity as it allows better coordination of cargo-handling operations.

Furthermore, in relation to the environment, the knowledge of ocean currents becomes useful in the event that pollutants like oil or chemicals accidentally spill into the ocean. With the nature of the cargo handled in this port, the spread of the spill needs to be forecast. The current data is thus useful in the swift execution of containment and mitigation measures to reduce environmental damage.

3. How do ADCPs using the Doppler principle work?

Principle of Measurement

ADCPs work on the principle of the Doppler effect. When an acoustic signal is transmitted by the ADCP meter into the water, it scatters off the moving water particles. Due to the presence of an ocean current, the water particles are in motion and, hence, they cause a frequency shift in the reflected acoustic signal received back by the ADCP profiler. This frequency shift, according to the Doppler effect, is proportional to the velocity of the flow.

Current Speed and Direction Calculation

By analyzing the magnitude and direction of this frequency shift, the ADCP flow meter can calculate the speed and direction of the ocean current at different depths in the water column. By emitting signals at multiple angles and different depths, it can create a profile of the ocean current, showing how the current varies with depth.

ADCP Deployment in the Port

Shipborne ADCP

A shipborne ADCP installed on ships operating within the Kokkola Port area emits acoustic signals continuously while moving around the port into the water underneath. The movement of the ship enables the ADCP current meter to cover an extensive area, gathering data about currents from various positions. For instance, when a research ship or an inspection ship installed with a shipborne ADCP conducts a regular surveying of the port, it will gain current pattern data from most areas of the port. Therefore, it gives the detailed current flow situation of water.

Fixed ADCP

Fixed ADCPs are deployed at discrete fixed locations in the port, for example, on the seafloor around areas of particular navigational importance or at the entrance/exit to the port. These ADCPs continuously record the ocean currents at their fixed positions over long periods. The collected data is helpful in analyzing the regular patterns of current in specific areas of the port. For instance, a bottom-moored ADCP installed near the entrance can continuously measure the in-flow and out-flow currents, which would help in assessing the tidal effects and other steady flow features of that area.

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

Equipment Requirements

Material reliability is the most important for high-quality measurement of the currents in Kokkola port. The equipment has to resist such a hard marine environment. Seawater contains salts and other chemicals which can gradually corrode materials. The equipment also needs to stand pressure changes at different depths of water and the mechanical force caused by waves and currents.

Secondly, a smaller size, lighter weight, and lower power consumption are desirable. A compact size allows for easier installation in various locations within the port, whether on ships, on fixed structures like piers, or on the seabed. A lighter weight simplifies the installation and transportation processes. The low power consumption ensures that equipment can run for long hours without the need for many battery replacements or excessive power supplies, which is crucial for applications that require long-term monitoring.

Cost is also an important aspect. The low-cost option allows a port to deploy more measuring devices for comprehensive current monitoring in different areas of the port.

The Advantage of Titanium Alloy for ADCP Casing

Titanium alloy will be an active preference of material in ADCP meter casing manufacture. Its high strength-to-weight ratio and excellent resistance to corrosion have made long - time exposure to sea water uninfluential with respect to its structure maintaining its own functional properties; accordingly, manufacture of durable, yet not very heavy casing is provided. For example, an ADCP current profiler  with a casing of titanium alloy will serve effectively in deeper parts of the Kokkola port where higher water pressures exist and provide valid current measurements.

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

Selection Based on Usage

Shipborne ADCP: Where the purpose of the measurement is wide surveys of the port waters besides the operation of the ship, shipborne ADCPs serve the purpose. A given ship may cover several portions of the port at various times, hence generating very many data points and visualizing the general picture across the entire port in regard to currents. It also enables the mapping of general patterns of flow and variations between different areas of the port waters.

Sitting-bottom ADCP: Long-term and fixed-point monitoring of some points in the port, such as near important infrastructures or areas with complex current behaviors, are more appropriate with sitting-bottom ADCPs. They can record the current data continuously at fixed positions, which is of great value for the study of local current characteristics and temporal changes.

Buoy-mounted ADCP: Where it is not convenient to install fixed equipment on the seabed or on ships, buoy-mounted ADCPs can be used. They float on the water surface and can measure the currents in the upper layers of the water column. They are relatively easy to deploy and can be relocated if needed, making them suitable for monitoring certain dynamic or hard-to-reach areas within the port.

Frequency Selection

The selection of frequency for ADCPs will depend on the water depth in different areas around the Kokkola port. Normally, an area with a water depth in the region up to 70 meters may be within the depth limit for choosing an ADCP current meter with the required frequency of about 600 kHz because of its adequacy for that depth's current measurement with good precision. For deeper waters up to about 110 meters, an ADCP current meter of 300 kHz is more advisable. And for really deep sections of the port with a water depth reaching up to 1000 meters, an ADCP flow meter with a frequency of 75 kHz is advisable to ensure reliable profiling of the ocean currents at such great depths.

There are several well-known ADCP profiler brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, there is also an excellent Chinese ADCP brand - China Sonar PandaADCP. It is made entirely of titanium alloy material, which not only ensures its durability in the marine environment but also offers an excellent cost-performance ratio. For more information, you can visit its official website: (https://china-sonar.com/).

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