ADCP in Milos Port: Ocean Current Measurement

1. Location and General Information of Milos Port

Geographical Location

Milos Port is located on the island of Milos in Greece. It is a port that benefits from its strategic position in the Aegean Sea. The island with its volcanic geology and beautiful coastline is a popular destination, and the port serves both commercial and tourist vessels.

Role in Local and Regional Trade

The port is very important to the local economy. It handles a wide range of cargo, from the island's agricultural products like olives and grapes to local handicrafts. It also acts as a point of discharge for vessels laden with construction materials, fuel, and other supplies necessary for the infrastructure and daily life of the island. Additionally, it welcomes cruise ships and ferries that carry tourists, thus helping in the tourism-driven economy of the island.

2. Port Facilities

Berths

The port has berths designed to accommodate different types of vessels. There are berths for small to medium-sized cargo ships, fishing boats, and cruise ships. These berths are equipped with modern mooring and docking facilities. High-quality fenders and bollards protect ships and berths during docking and undocking.

The depth of water in the berths is kept to allow vessels of various drafts to safely dock. There may be periodic dredging operations to maintain access to the berths.

Cargo-handling Equipment

On the quay, there are cargo - handling equipment that vary in kind. Forklifts and small cranes transfer goods to and from the ships and storage areas in cases of agricultural products and handicrafts, while for construction materials and other bulk goods, including fuel, there are conveyor systems and larger cranes. Special equipment also exists for the handling of supplies and luggage in cruise ships.

Storage Facilities

There are storage areas for different types of cargo. For perishable agricultural products, there are well-ventilated warehouses and cold - storage facilities. For construction materials and other non - perishable goods, there are stockpiles and covered storage sheds. The port also has storage areas dedicated to cruise ship supplies and tourist - related goods.

Channel and Navigation Aids

The port's channel is maintained to a suitable depth and width to allow the safe passage of ships. Navigation aids such as buoys, beacons, and a radar system are in place. The radar system provides real - time information about the position and movement of other vessels in the vicinity of the port, ensuring safe navigation.

3. Importance of Measuring Ocean Currents in Milos Port

Safety of Vessel Navigation

Ocean current measurement is very important in terms of vessel safety. During the approach of ships to berths or while navigating the channel, information on the speed and direction of the current is needed. A cross-current near a berth can make docking a challenging and dangerous process.

For instance, a ship trying to dock against a strong current may need to adjust its speed and angle of approach. Precise current measurements enable the captains of ships to make informed decisions that reduce the possibility of collisions and other accidents.

Optimization of Port Operations

Current data is useful in the optimization of port operations. Knowledge about tidal currents and other flow patterns that occur periodically enhances the ability of port authorities to plan the arrival and departure times of ships.

Thereby, berthing could be managed more effectively and loading and unloading activities could be well planned. Consequently, it may result in higher output due to better coordination between cargo-handling operations.

In the event of an accidental discharge of pollutants like oil or chemicals, ocean currents are of prime importance. Considering the type of cargo handled in the port, prediction of the spill spread using current data can quickly deploy containment and mitigation measures to minimize environmental damage.

4. Working Principle of ADCPs (Acoustic Doppler Current Profilers)

Doppler Principle

ADCPs are based on the principle of Doppler. When an ADCP current meter sends an acoustic signal into the water, it interacts with the moving water particles. As the water particles are moving due to the current in the water, they shift the frequency of the reflected acoustic signal arriving back at the ADCP current profiler.

According to the Doppler effect, this frequency shift is related to the water flow's velocity; the magnitude of the frequency shift is proportional to the speed of the water particles.

Current Speed and Direction Calculation

By analyzing the magnitude and direction of the frequency shift, the ADCP flow meter can calculate the speed and direction of the ocean current at different depths in the water column.

The ADCP profiler sends signals with several angles and depths from where the profile of an ocean current is recorded out. It clearly shows the structure of a current, depicting at which depth it alters in a drastic manner.

5. Milos Port ADCP Deployment

Shipborne ADCP

A shipborne ADCP can be installed on ships operating in the Milos Port area. While the ship is moving in the area of the port, the ADCP current meter continuously sends acoustic signals into the water underneath it. The movement of the ship enables the ADCP meter to cover a wide area and gather the current data from a diverse set of areas.

For instance, in a routine survey of the port by a research or inspection ship equipped with a shipborne ADCP, it can gather data on various parts of the port on the current patterns, thus giving a comprehensive understanding of the water flow situation.

Fixed ADCP

Fixed ADCPs can be placed at specific, stationary locations within the port, such as on the seabed near important navigational areas or at the entrance/exit of the port. These ADCPs continuously monitor the ocean currents at their fixed positions over a long period.

The data obtained by fixed ADCPs is helpful in analyzing the periodic current patterns in selected areas of the port. As an example, a fixed ADCP at the vicinity of the entrance of the port may record the currents incoming and outgoing, thus helping to understand the effects of the tide and the other regular flow characteristics in that area.

6. Requirements for High - Quality Measurement of Milos Port Currents

Equipment Characteristics

Material Reliability: The equipment should be resilient enough for the marine environment. Seawater contains salts and other chemicals that may corrode materials over time. It also has to endure pressure variation in different water depths and the mechanical forces of waves and currents.

Size, Weight, and Power Consumption: As small in size, as light in weight, and with low power consumption as possible. A compact size will accommodate installations in various port locations such as on ships, piers, or the seabed. In addition, lighter weight makes installation and transportation easier. The devices must be able to provide continuous operation for a very long period without frequently exchanging batteries or excessive power supplies, which is important for long-term monitoring.

Cost: Cost is a major factor. A lower-cost alternative will enable the port to deploy more measuring devices for extensive current monitoring across different areas of the port.

Advantage of Titanium Alloy for ADCP Casing

The casing of ADCPs is preferred to be made of a titanium alloy. Titanium alloy has great corrosion resistance; it can maintain its structural integrity and functionality after being exposed in seawater for quite some time.

Its high strength-to-weight ratio allows for a robust and yet relatively lightweight casing. An ADCP current meter with a casing made of titanium alloy will be able to withstand the increased pressure in the deeper areas of Milos port while providing current measurements with great accuracy.

7. Current Measurement Equipment Selection

Application-Based Selection

Shipborne ADCP: When the intention is to conduct wide-area surveys of the port waters, and when the ship is operational, then the shipborne ADCP will be appropriate. In this, the ship while moving can cover various parts of a port and generate a substantial quantity of data to map the general flow patterns and their variation within the overall current in the port area.

Sitting-bottom ADCP: Sitting-bottom ADCPs are more suitable for long-term and fixed-point monitoring of some places in the port, such as near important infrastructure or areas with complex current behaviors. They can continuously record current data at fixed positions, providing insights into local current characteristics and changes over time.

Buoy-mounted ADCP: It is used when it is not convenient to install fixed equipment on the seabed or on ships. They float on the water surface and measure currents in the upper layers of the water column. They are easily deployed and can be relocated; hence, they are suitable for monitoring dynamic or hard-to-reach areas.

Selection Based on Frequency

Depending on the water depth of Milos port, the choice of frequency for ADCPs would be made. Normally, up to 70 meters of water depth, 600 kHz is a good frequency of an ADCP to give reasonably accurate current measurements.

For deeper waters up to around 110 meters, an ADCP flow 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.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. Additionally, there is an excellent Chinese ADCP brand-China Sonar PandaADCP. It is made of titanium alloy, ensuring durability in the marine environment and offering a good cost-performance ratio. For more information, visit its official website: (https://china-sonar.com/).

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