How can we measure the coastal currents of Valencia?

1. Where is Valencia?

Valencia is a very lively city situated on the east coast of Spain. It finds itself between the mountains and the Mediterranean Sea, making it a unique geographical location. The city boasts some beautiful, sandy beaches running along the coast, which attracts many tourists.

The cultural and historical landscape of the Valencia region is diverse. In itself, the city is a contrast from old to new architecture. From the historic City of Arts and Sciences, truly a landmark of modern innovation, to the ancient buildings and narrow streets of the old town, Valencia presents an urban diversity that few other cities can match. Its surroundings constitute a countryside famous for the fertility of its soil, one of the typical features being orange groves.

Off the Valencia coast is the Mediterranean Sea. The waters are usually calm since it is part of the Mediterranean and not the turbulent Atlantic Ocean. The bottom slopes gently down, with the depth going from shallow near the coastline to deeper further out. The marine life here is varied, including a wide variety of fish species and other organisms. This area also consists of a Mediterranean climate with mild winters, hot and dry summers; these climatic conditions directly affect the temperature of the sea, hence influencing coastal currents.

2. What is the situation of the coastal currents around Valencia?

As for the general characteristics, the coastal currents around Valencia come into contact with many influencing elements. The Mediterranean Sea takes the first major position in its current circulation. The large-scale anti-clockwise circulation in the Western Mediterranean has an effect on the water circulation in the area. Tides will also play a role, although generally the tidal range is less than in many other seas. The tides can cause the water to move in and out, although with less force than in more tidally dominated areas.

Another important factor is that of the local winds. These surface currents can be driven by the prevalent winds in the area, such as the easterly and westerly winds. During summer, the sea breeze can have a notable effect on the movement of surface water. The topography of the seabed, including the presence of underwater ridges and valleys, can redirect and modify the currents. Besides, the discharge of fresh waters and input through the local rivers modifies the salinity of coastal waters that determines the current patterns.

3. How to measure the coastal circulation of Valencia?

The method Surface Drift Buoy. This consists in throwing buoys onto the surface of waters that drift according to any type of incident currents. These buoys are carried by the surface currents, while their movement can be tracked using satellite-based or other tracking systems. In such a way, the direction and speed of the surface currents are calculated by following the trajectory of the buoys over time. However, this method provides information only on the surface layer and may not give a comprehensive view regarding the currents at different depths.

The anchored ship itself can be used as a platform for current measurement. The instruments installed on the ship will measure the water flow around it. This can provide more precise measurements of one particular location but is confined to the immediate vicinity of the anchored ship and may be influenced by the ship interfering with the flow of water.

ADCP current meter is one of the sophisticated and efficient means of measuring the currents in the coastal waters. It detects the velocity at several depths simultaneously by applying sound waves to measure water particle motion. Emitting acoustic pulses and analyzing the Doppler-shifted reflections, ADCP current profiler offers a detailed current profile from surface to a certain depth. Compared with the other methods, this method provides a further detailed analysis of coastal currents around Valencia.

4. How does the ADCP based on the Doppler principle work?

The working principle of ADCPs is based on the Doppler effect. An ADCP flow meter sends acoustic signals-usually in the form of short pulses-into the water. Because of the Doppler effect, the pulses reflected from moving water particles produce a frequency shift. This frequency shift depends upon the velocity of the water particles.

A number of transducers fitted with the ADCP send and receive the signal in multiple directions. From these different directional frequency shifts, the ADCP meter calculates velocity components of the water, both in the horizontal and vertical directions. Because the acoustic pulses are generated at regular periods and at many depths, the profile of current velocities at every depth is determined throughout the height of the column of water. This gives the valuable information on flow patterns, such as the direction, speed, and any vertical shears in the currents.

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

For high-quality measurement of the coastal currents near Valencia, the equipment needs to be made from reliable materials. Materials should be able to resist the saltwater corrosion, changes in pressure, and possible impacts, with seawater being corrosive and the marine environment sometimes very harsh. Small size and light weight will be quite favorable to enable easy deployment, whether on a ship, a buoy, or on the seabed. The power consumption should be low to enable long-term operations without frequent changes of batteries or disruption of power sources. Besides, cost-effectiveness is also a significant factor in order to enable large-scale measurements.

Coming to the ADCP profiler casing, Titanium alloy can become one superior option. These have an exceptionally outstanding resistance to corrosion, so urgent for putting up in the seawater environment inshore off Valencia, and an amazingly huge strength-to-weight proportion, insuring a pretty sufficient stiffness protecting internal parts of the instrument by keeping its entire weight rather at a low value to allow for effortless handling and placement.

6. How to choose appropriate equipment to measure current?

Depending on Deployment Method

• Ship-borne ADCP: It is the suitable one if you want to measure the currents of the ship while it moves along the coast or stays at a place. It provides flexibility in covering different areas and can give continuous data as the ship changes position.
• Bottom-mounted ADCP: Good for fixed-point measurements from the seabed. It can give long-term and accurate data of the current conditions at a specific location, which is useful for understanding the local current patterns.
• Buoy-mounted ADCP: The upper layer currents can be measured by it while attached with a buoy floating on the water surface. Besides, it can transmit the data wirelessly, which means that it would be convenient for use in remote monitoring and may cover a wide area given that the buoy can move over great distances.

Frequency-based

With differing frequencies are the best uses in different water depths, how a 600 kHz ADCP is intended for water no deeper than 70 meters. It would follow that in deeper waters, say 110 meters and over, one would use a 300 kHz while an upward of 1000 meters would call for an ADCP in the 75 kHz range. From this information, you will be better equipped to understand which is better based on conditions of water depth specific to the Coastal Area of Valencia.

There are well-known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, a Chinese brand, China Sonar PandaADCP, is also a great option. It is made of all-titanium alloy material, ensuring durability and offering an excellent cost-performance ratio. You can visit their website at https://china-sonar.com/ for more information.

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