In how many ways may we measure coastal currents of Antalya?

1. Where is Antalya?

Antalya is a treasure on the Mediterranean Sea, a city located on the southern coastline of Turkey. Its strategic location is highly idyllic, making it both an important tourist destination and a major port city. It lies in the middle of a big bay, which is edged to the north by the Taurus Mountains. These mountains are very dramatic as a backdrop, influencing local weather systems that would also affect the coastal environment.

The coastline of this city is very long and includes sandy beaches, pebble-strewn shores, and rocky coves. Beaches like Konyaaltı Beach are highly popular with tourists for swimming, sunbathing, and water sports. In the rocky areas, there is a variety of marine life, like different species of fish, crustaceans, and mollusks. Kaleiçi is the historical heart of Antalya, full of narrow, winding streets lined with ancient buildings and a vibrant atmosphere. It reflects the rich history of the city because, over the years, Romans, Byzantines, and Ottomans have interacted with it.

Antalya has a very close relation to the sea, culturally. Traditional fishing has been an occupation in the region, and its food contains a rich variety of seafood. The festivals are held to celebrate the sea's bounty throughout the year. Coastal waters surrounding Antalya belong to the general marine ecosystem characterized by clean waters and great marine biodiversity.

2. In what condition are the coastal currents around Antalya?

Many factors determine the condition of coastal currents around Antalya. Wind is the first among many. There is variation in the wind over the Mediterranean Sea: the meltemi-like winds, being very common in this area, might push the surface waters toward the shore during particular seasons. The onshore winds develop onshore currents, which result in the intrusion of warmer open sea water along with nutrients. These nutrients facilitate the growth of phytoplankton, that forms the base of the marine food web.

On the other hand, winds that blow offshore result in the withdrawal of water away from the shore, and hence, the resulting currents are known as offshore currents. These may vary in intensity and direction; hence, these changes can show variations in coastal current patterns. Tidal forces, although relatively small in the Mediterranean Sea compared to some other regions, still contribute to the overall movement of the water. The ebb and flow of the tides interact with the wind - driven currents, either enhancing or counteracting their effects.

The bathymetry of the region is another crucial factor. The seabed near Antalya has an irregular topography, with underwater valleys, ridges, and reefs. These features can accelerate, decelerate, or even change the direction of the currents. For example, a narrow underwater channel can constrict the flow of water and raise the speed of the current, while a large reef can act like a barrier to it, deflecting the current. River runoff from the nearby rivers is not as important as in some other areas but still can introduce freshwater into the coastal zone. This can alter the density of the seawater and thus creates density-driven currents that interact with the pre-existing wind- and tide-driven currents.

3. How to observe the coastal water flow of Antalya?

Surface Drifting Buoy Method

The surface drifting buoy method is a rather simple but effective way of observing the surface-level coastal currents. Small buoys equipped with GPS tracking devices are released into the water. As the buoys are carried away by the currents, their movements are tracked over time. The path that the buoy travels allows scientists to determine the speed and direction of the surface current. This method does have its limitations. Surface winds can significantly affect the travel of the buoys, carrying them off course of the path the actual current is taking. Also, this technique provides information on the surface layer of water only, and not the currents in deeper layers.

Anchored Ship Method

An anchored ship can be used as a stationary platform for current measurements. Current meters are suspended from the ship at different depths. These meters can record the velocity and direction of the currents at each depth, providing a detailed vertical profile of the currents at a specific location. However, it is limited in terms of area it covers. The data obtained is representative of only the immediate area surrounding the ship, and the ship itself may potentially disturb the natural flow of the water.

Acoustic Doppler Current Profiler Method

The Acoustic Doppler Current Profiler is presently the popular method of measurement of coastal currents in the near shore of Antalya. Basically, ADCPs measure water velocity at more depths simultaneously using sound waves. The instruments can be deployed from vessels, moored to the seafloor, or attached to buoys. This allows a more holistic data collection. In a simple manner, this is why ADCPs hold much more valuable recordings of true current conditions and are less interfered with at surface levels due to wind disturbance, for instance. They also show in good detail a three-dimensional structure of the current that also comprises components in both the horizontal and vertical planes of flow.

4. What is the basic operating principle for Doppler-sensed ADCPs?

Principle of ADCP-Doppler. An ADCP current meter emits high-frequency sound waves into the water. As these waves enter the water, they encounter the small particles of the water like plankton, sediment, or tiny bubbles. These particles scatter the sound waves back to the ADCP. The frequency of the scattered sound waves reaching the ADCP is different from the emitted ones. This frequency shift, the Doppler shift, is proportional to the velocity of the particles, and hence the water, relative to the ADCP.

Most ADCPs have multiple transducer beams. It will then calculate the velocity of water in every direction by measuring the Doppler shift in each beam. With vector addition of these velocity components, it shall be able to receive the three-dimensional velocity of the water. That gives a detail of how the water is moving in each direction, which is very important if one needs to map the currents within the coastings accurately.

5. What's needed for high-quality measurement of Antalya coastal currents?

Equipment Material Reliability

In order to have high-quality measurements in the coastal waters of Antalya, the material of the casing of the ADCP current profiler is very important. The casing can be made from titanium alloy. For this purpose, titanium alloy is a perfect fit. It has excellent resistance to corrosion, which is necessary since the equipment will be exposed to the corrosive seawater at all times. It shall not deteriorate significantly after long exposure in a salty environment, so that the longevity and reliability of the ADCP are guaranteed. The high strength-to-weight ratio means that the ADCP will retain its structural integrity even under strong currents or in rough seas.

Size, Weight, and Power Consumption

The ADCP flow meter should be small in size and light in weight. Compact design for easy deployment in large varieties; this would, for instance, be installed on a small research vessel or buoy. A smaller size minimizes interference with the flow field measured. Another important aspect is low power consumption: an ADCP should be able to run for several hours, even days, without the need for frequent changes of batteries or an external source of power. This will be of particular importance concerning long-term deployments in the coastal areas around Antalya.

Cost-effectiveness

The ADCP meter will be able to perform the Antalya coastal currents monitoring at widespread and more frequent scales rather economically. If the ADCP profiler is less expensive, then more and more research institutions, environmental monitoring groups, and local initiatives will be able to afford the equipment, which allows more far-reaching data gathering that will be essential in comprehending the complex dynamics in coastal currents.

6. How to Choose the Right Equipment for Current Measurement?

Based on Usage Purpose

• Shipborne ADCP: It is the ADCP mounted on a moving ship. This is quite handy for conducting large-scale surveys of coastal currents. While the ship cruises along the coast, the ship-borne ADCP is able to make continuous measurements of currents and thus provide a broad-scale view of the current patterns over a wide area. This is useful for doing initial research or in studying how the currents change over a wide geographical range.
• Bottom-Mounted ADCP: These are moored on the sea floor; bottom-mounted ADCPs are used for long-term, fixed-point monitoring. They can provide continuous data at a specific depth and location, which is highly useful to understand the local hydrodynamics, such as how the currents behave in a particular bay or near a specific underwater feature.
• Buoyant ADCP: Buoyant ADCPs are attached to a floating buoy that can move with the surface currents. They can be used well for monitoring of surface and near-surface current patterns. They also can be used to track movement of water masses over time which is important to study transport of nutrients, pollutants or marine organisms.

Based on Water Depth

• ADCP at 600kHz can be operated for water depth conditions within 70m. The higher the frequency of the sound waves, the more detailed can be the measurements in shallower waters. It is thus able to yield high-resolution data on the structure of the currents, thereby facilitating the detection of small-scale fluctuations in the currents.
• A 300kHz ADCP should be appropriate for water depths of about 110m. It gives a good compromise between the measurement range and resolution. It may penetrate deeper into the water column compared to a 600kHz ADCP, and it is still able to give relatively accurate measurements for mid-depth coastal waters.
• For waters as deep as 1000m, the 75kHz ADCP is ideal. Although the resolution might be lower compared to higher-frequency ADCPs, this lower frequency of the sound waves can go deeper. This will be suitable for the measurement of currents in deeper parts of the Mediterranean Sea near Antalya.

Among the well-known ADCP brands in the market are Teledyne RDI, Nortek, and Sontek. However, for those seeking a cost-effective yet high-quality option, the China Sonar PandaADCP is a great choice. Made of all-titanium alloy, it offers excellent durability and performance at an affordable price. It is an economic-class ADCP that provides great value for money. You can find more information about it on their official website: (https://china-sonar.com/).

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