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

1. Where is Thessaloniki port?

Thessaloniki port is in the city of Thessaloniki, Greece. It is one of the major ports in the Aegean Sea area.

Port Scale and Throughput

The port of Thessaloniki has a considerable scale, with highly diverse cargo such as container cargo, general cargo, and bulk cargo, handled through the port each year and thus reflecting its importance in both the regional and international trade network. The handling of containers, facilitated over time, especially during the past years, assists in carrying various items, including manufactured products, agricultural produce, and industrial raw materials.

Routes and Business

It is an important link to many shipping routes. It connects Greece with other Mediterranean countries and ports in Europe and the Middle East. The business activities in the port cover imports and exports of a wide array of commodities. For example, it imports machinery and equipment for the local industries and exports agricultural products like olive oil and wine.

Port Management and Operation

The port is well-managed, keeping efficiency and safety in mind. The day-to-day operations under the management of the Port Authority include the berthing of vessels, cargo handling, and customs procedures. Advanced port management systems ensure the smooth movement of goods and ships at the port. The facilities provided include services related to warehousing and logistics support that further enhance the efficiency level of the supply chain.

Port Facilities

The port of Thessaloniki has been equipped with modern facilities. This includes various berths that can accommodate various vessel types, from the smallest coastal ships to large container carriers, cranes, and forklifts for advanced cargo-handling in order to facilitate goods loading and unloading. Storage areas are available to accommodate different types of cargo, including temperature-controlled storage for perishable items.

Channels and Direct Routes The port has well-maintained channels that ensure a safe passage for ships. The channels are dredged frequently to keep the depth sufficient for vessels. Direct shipping routes connect Thessaloniki with major ports in the Mediterranean and beyond, making it important in maritime trade.

2. Why do we need to measure the sea currents in the Thessaloniki port?

Precise measurement of ocean currents in the Thessaloniki port is of utmost importance for its operation and management. Ocean current data are useful in optimizing vessel navigation. With the knowledge of current patterns, ships would be able to adjust their speeds and routes to minimize fuel consumption and travel time. For instance, a ship could make use of favorable currents to speed up its journey into or from the port.

It is also an essential factor in the safety of port operations. Powerful and unanticipated currents can create hazardous conditions for berthed vessels to collide or damage the docking facilities. The port authorities can monitor the currents in order to take precautionary measures regarding the mooring arrangements of ships.

Current measurements are required for the efficient performance of a number of marine operations, such as dredging and underwater construction. The data can also be used to determine when and where the operation is best executed.

Compared to other methods, it is more modern and convenient in measuring ocean currents: Acoustic Doppler Current Profiler (ADCP). With this device, real-time and continuous data may be acquired, thus providing a more accurate interpretation of the current dynamics in the port area than would be possible with traditional measurement methods.

3. How do ADCPs using the Doppler principle work?

Principle: ADCPs are based on the Doppler effect. They transmit acoustic signals into the water and measure the frequency shift of the reflected signals from particles moving with the water current. The frequency of the received signal will change due to the Doppler effect, depending on the velocity of the reflecting objects, here the particles in the water current.

Ship - borne acoustic doppler velocity meter

With the use of a shipborne ADCP, the device is fixed on a vessel. During the movement of the vessel through the water, an ADCP sends acoustic pulses in either a downward or sideward direction. The signals that get reflected from the water column are received, and further the Doppler shift is analyzed for the determination of the water current at different depths. This enables profiling of the present structure while the vessel travels across the area.

Fixed ADCP

Fixed ADCPs are mounted on structures such as piers or buoys. They continuously monitor the water current in a location. The acoustic signals are usually transmitted downward or in a specific angular range. Analysis of the Doppler-shifted return signals allows the measurement of current velocity and direction with time, hence providing long-term records of the current behavior at that location.

4. What is required for high - quality measurement of Thessaloniki port currents?

High - quality current measurement in the Thessaloniki port requires a number of features in the equipment. First of all, the materials used during the construction of the ADCP current profiler should be reliable. Small size and light weight are welcome since it allows for easier installation and transportation, especially for ship - borne and buoy - based ADCPs.

Low power consumption is also crucial, especially for long - term fixed - point measurements. This ensures that the equipment can operate continuously without the need for frequent battery replacement or external power source maintenance. Cost - effectiveness is another important factor as it enables the use of multiple devices for more comprehensive coverage of the port area.

The casing of ADCP flow meter is preferably made of titanium alloy. It is highly resistant to corrosion, which is really essential in the marine environment. Seawater in the port can cause serious corrosion to ordinary metals. Because of this, titanium alloy will never be affected by the corrosiveness of seawater, making sure that the equipment lasts a long time. It also has high strength-to-weight ratio to help reduce the overall weight of the device, while keeping the structure at its best.

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

Depending on the exact application, different types of ADCP equipment will be employed.

Based on Usage

Ship - borne ADCP: Where currents are required while in transit, then a ship - borne is quite applicable. It offers the profile of currents along the ship's path, and that aids navigation and helps make proper operational decisions.

Bottom - mounted ADCP: For long - term and fixed - point monitoring of currents near the seabed, a bottom - mounted (sit - on - bottom) ADCP is a good option. It can provide continuous data about the current behavior at a specific location, such as near the entrance of the port or around critical underwater structures.

Buoy-based ADCP: This can be employed when the goal is to monitor currents within a specific area over some period and have the flexibility of mobility to some extent. It can be deployed even in areas where ships may not regularly pass but are still significant to understand the overall current pattern in the port.

Based on Frequency

It is also imperative to consider the right frequency for operation. The commonly used and ideal frequency is 600kHz for ADCPs and shallower waters not beyond 70m. An instrument of frequency of 300kHz would go down better in depths around 110m whereas a 75kHz ADCP will be quite fitting for depths of up to 1000 m that may come as approaches toward the port.

There are several well - known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, a recommended Chinese brand is China Sonar PandaADCP. It is made of all - titanium alloy material, which provides excellent durability. It also offers an incredible cost - performance ratio. You can find more information about this brand on its website: (https://china-sonar.com/).

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