ADCP's Application to Ocean Current Measurement in the Port of Kemi

1. Where is Kemi Port?

Overview of Kemi Port

Kemi is a port located in the city of Kemi, which falls in the region of Lapland within Finland. It is considered an important port in the northernmost part of the country with a strategic location near the Arctic Circle. The moderate scale and throughput of cargo, relevant to the local and regional economy, characterizes it.

It forms the very important transportation link to the local forestry and mining industries. Products exported from this port include forest products like timber and pulp, along with minerals extracted from the region. Goods imported include raw materials necessary for various local industries and communities. The management at Kemi Port is looking to enhance operations efficiently, with the different teams taking care of vessel traffic management, cargo handling, and other functions related to the port.

Port Facilities

Berths: Kemi Port has various berths for receiving vessels of different types. The port has berths for medium-sized cargo ships and barges. The facilities are appropriately fitted with mooring and docking facilities that ensure the safe arrival and departure of the ships. The fenders and bollards protect both the ships and the berths from any damage during the process of docking and undocking.

Cargo-handling Equipment: There is a range of cargo-handling equipment along the quay. For handling forest products, there is a crane and conveyor system that can efficiently move logs and pulp; for bulk minerals, there are grabs and conveyor belts that can transfer the materials from the ships to the storage areas.

Storage Facilities: Pockets of storage facilities for the varied cargo exist. Stockpiles for forest products that provide adequate protection against unfavorable weather conditions exist, while minerals have appropriately located storage facilities with containment features in case of spillages. Other general cargo materials can also be stored in different facilities at the port.

Channel and Navigation Aids: Maintenance in the channel is assuredly done to an appropriate depth and width for safe passage for the ships. Regular dredging operations are done to make it navigable for vessels with different drafts. There are navigation aids such as buoys, beacons, and radar systems to guide the ships into and out of the port. The radar systems give real - time information on the position and movement of other vessels in the vicinity of the port.

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

Significance to the Operation and Management of the Port

The measurement of ocean currents at Kemi Port is quite an important issue. Firstly, for safe vessel navigation, knowledge about the current speed and direction by ship captains is necessary to approach berths or when navigating along the channel. A strong cross-current in the vicinity of a berth may turn the process of docking into a difficult and hazardous one. For example, a ship approaching a berth against a strong current may have to adjust its speed and angle of approach to ensure smooth and safe docking. Precise measurements of current enable captains to make informed decisions and decrease the risk of collisions and other types of accidents.

Second, it is crucial for the optimal functioning of the port. A recent record is helpful for planning the arrival and departure timings of ships in a coordinated manner. The knowledge of tidal currents, among other periodic flow patterns, allows the port authorities to manage the berthing accordingly and to schedule the operation of loading and unloading. This further enhances efficiency as it enables better planning of cargo-handling jobs.

Besides, knowledge of ocean currents is useful from an environmental perspective, especially in the event of accidental spills of oil or chemicals. The nature of cargo handled at the port calls for such a prediction of spill spread. This data can then be used to quickly institute containment and mitigation measures in order to minimize environmental damage.

3. How do ADCPs using the principle of Doppler work?

Measurement Principle

ADCPs work on the principle of the Doppler effect. In this, an acoustic signal is transmitted into the water by the ADCP profiler. Moving water particles interact with this signal. Because the water particles are moving owing to the ocean current, they cause a frequency shift in the reflected acoustic signal received back by the ADCP flow meter. This frequency shift, by the Doppler effect, is proportional to the velocity of the flow of water.

Calculation of Current Speed and Direction

By analyzing the magnitude and direction of this frequency shift, the ADCP current 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 in the Kemi Port area continuously sends acoustic signals into the water from which it is moving. The movement of the ship enables the ADCP to cover a wide area and collect current data from different locations. For instance, a research or inspection ship with a shipborne ADCP current profiler that conducts a routine survey of the port can obtain current patterns across different areas of the port for a comprehensive understanding of the water flow situation.

Fixed ADCP

The fixed ADCPs are placed at a certain stationary position within the port, either on the seabed of some important navigational areas or at the entrance or exit of a particular port. These ADCPs perform monitoring of the ocean currents at their fixed position continuously for a long time. Thus, these data become quite useful to analyze the regular current patterns at a specific area within a port. For example, a bottom-moored ADCP installed at the port entrance can measure the currents flowing in and out, which can be used to understand the tidal effects and other consistent flow characteristics of that area.

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

Equipment Requirements

For high - quality measurement of the currents in Kemi port, some equipment characteristics are vital. First of all, material reliability is the most critical issue. It has to resist the heavy marine atmosphere. Seawater contains salts and some other chemical substances which will destroy any material in the long run. Equipment also has to stand the pressure variations created by changing depth of the water, and mechanical strengths caused by waves and currents.

The second is the demand for smaller size, less weight, and lower power consumption. The compactness in size allows for quick installation in various locations at a port, whether on ships or fixed structures like piers or the seabed. A lighter weight will make the installation process easier, as well as transportation. Less power consumption means the devices can go many hours, in fact continuous, without any battery changes, or excess supply of current, which becomes very helpful at all moments, especially when it's the case of monitoring over some long time periods.

Also, cost plays a factor. A low-cost version allows the port to be able to use more devices for the purposes of flow measurement for general coverage and tracking of currents around different port locations.

Advantage of Titanium Alloy for ADCP Casing 

The casing of the ADCPs is preferably of a titanium alloy. The very excellent corrosion resistance of this will assure maintenance of the structural integrity and functionality of this alloy even after a reasonably longtime exposure to seawater. The high strength-to-weight ratio allows for the building of a durable yet lightweight casing. For instance, in those parts of the Kemi port that are deeper and where higher pressures of water exist, an ADCP current meter with a casing of titanium alloy can resist such pressures effectively while measuring the current correctly.

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

Selection Based on Usage

Shipborne ADCP: Where the intention is to carry out wide-area surveys of the port waters, and the ship is operational, then shipborne ADCP is appropriate. It can cover different sections of the port as the ship moves around, collecting a large amount of data to provide a comprehensive understanding of the overall current situation in the port. This is useful in mapping the general flow patterns and variations across different areas of the port waters.

Sitting - bottom ADCP: For long - term and fixed - point monitoring of specific locations within the port, such as near important infrastructure or areas with complex current behaviors, sitting - bottom ADCPs are more appropriate. They can continuously record the current data at those fixed positions, providing valuable insights into the local current characteristics and any changes over time.

Buoy-mounted ADCP: When 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, thus making them suitable for monitoring certain dynamic or hard-to-reach areas within the port.

Selection Based on Frequency

The choice of frequency for ADCPs depends on the water depth in Kemi port. For areas with a water depth of up to 70 meters, an ADCP flow meter with a frequency of 600 kHz is usually a good choice as it can provide accurate current measurements in this relatively shallow depth range. When dealing with deeper waters up to around 110 meters, an ADCP current meter with a frequency of 300 kHz is more advisable. And for extremely deep sections of the port with a water depth reaching up to 1000 meters, an ADCP with a frequency of 75 kHz is recommended to ensure reliable profiling of the ocean currents at such great depths.

There are several well - known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, there is also an excellent Chinese ADCPbrand - 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.