How to measure coastal currents in Murcia?

1. Where is Murcia?

The Region of Murcia is in southeastern Spain and has a Mediterranean coastline. The town or city of Murcia is the capital and lies some little way inland; however, the coasts of this autonomous community are extremely relevant. Its coastal strip contains many wonderful beaches and coves.

The Murcia coastline belongs to the Mediterranean coastal landscape. The sea bottom off the coast of Murcia is quite shallow with a soft slope that goes down very gently. Ichthyofauna and shellfish include a rich variety of species in these waters, along with many types of seaweed. The Mediterranean climate in Murcia is characterized by hot and dry summers and mild winters. This Mediterranean climate conditions the temperature and salinity of the coastal waters.

The tourism industry in this area is one of the largest human activities, as most people are attracted by the sandy beaches and clean waters. Fishing has also been recorded as part of the local economic activities, where the coastal waters offer a rich fishing ground.

2. What is the situation of the coastal currents near Murcia?

The general setting of coastal currents near Murcia is brought about by several factors. The general circulation patterns of the Mediterranean Sea have a prominent effect. The anti-clockwise circulation in the Western Mediterranean makes an effect on the water flow in the area. The tides also have a role, though the tidal range in the Mediterranean is comparatively small. Due to the tidal currents, there is a regular back-and-forth movement of water, though less strong as in regions with more considerable tides.

The local winds are indeed a major driving factor. Surface currents can, in fact be driven by the prevailing winds- the easterlies and the westerlies. The summertime sea breeze can result in more marked variations in surface-currents. The general topography of the ocean floor is responsible for their deflection and alteration. Also, any freshwater discharges from the rivers will result in the dilution of coastal waters, so the density varies and it results in variations of current patterns.

3. How to Observe Coastal Water Flow in Murcia?

The technique of surface drift buoys follows surface drift buoys floating on the surface of the water. The surface currents move them, and satellite-based tracking system, amongst others may locate them. The direction and speed of surface currents are attained by analyzing the movement of these buoys over time. This mainly consists of information about the surface layer, though, and may not give an accurate picture at other levels.

Anchored Ship Method: An anchored ship can serve as a platform for the measurement of current. Instruments are installed on the ship to measure the flow of water around it. It allows for more accurate measurements at a specific location, but it is limited to the area around the anchored ship and may be affected by the ship's interference with the water flow.

ADCP Method: The ADCP method is more sophisticated and efficient for measuring coastal currents, using sound waves for the measurement of water velocity at different depths all at once. It emits acoustic pulses, and from the Doppler-shifted reflections, ADCP is able to obtain a detailed profile from the surface down to a certain depth. This allows for an understanding of the coastal currents in Murica to a larger scope than other means.

4. How do ADCPs based on the principle of the Doppler effect work?

The ADCPs work on the principle of the Doppler effect. They emit acoustic pulses into the water. When these sound waves meet the moving water particles, the frequency of the reflected waves shifts due to the Doppler effect. The change in frequency is proportional to the velocity of the water particles.

The ADCP has multiple transducers that are capable of sending and receiving signals in different directions. Since it measures the Doppler frequency shifts in different directions, the ADCP can estimate the velocity components of the water in both horizontal and vertical directions. Because the acoustic pulses are transmitted at regular time intervals and at different levels, a profile of the current velocities throughout the column of water is made. This yields an insight into the flow pattern of the flow direction, flow speeds, and even any possible vertical shears in the currents.

5. What is required to obtain high-quality measurement of the Murcia coastal currents?

In obtaining a high-quality measurement of coastal currents near Murcia, the necessary equipment should possess reliable materials. Consider seawater being corrosive and thus the general marine environment sometimes perhaps harsh, so it should definitely be important that these materials could not corrode from seawater, changes in pressure, and other possible influences that could take place underwater. Small in size, lightweight to ensure good deployment either from a ship or on the buoy or seabed floor. Long-time operability implies low power consumption to avoid any frequency in replacing batteries or other kind of disrupters in the supply of energy sources. Besides, cost-effectiveness is also another important factor for large-scale measurement.

On matters of casing, ADCPs are excellently made with titanium alloy. Titanium alloy is very resistant to corrosion, important to the corrosive seawater environment in Murcia. It has a high strength-to-weight ratio, implying that it can provide strength to protect the inner components while allowing the overall weight of the device to be kept relatively low, hence easy to handle and install.

6. How to Select appropriate equipment for current measurement?

Depending on the Deployment Method:

• Ship - borne ADCP: This is ideal when one wants to measure the currents while the ship is either in motion along the coast or remains at a specific location. This offers the flexibility of covering different areas and provides continuous data with every change in position of the ship.
• Bottom-mounted ADCP: This is best suited for fixed-point measurements from the seabed. It is capable of yielding long-term, high-accuracy current conditions over a certain spot that could be useful for deducing local current patterns.
• ADCP mounted on a buoy: When attached to a buoy floating on the water surface, it is able to measure the currents in the upper layers and transmit the data wirelessly. This is convenient for remote monitoring and, therefore, can cover a wide area depending on the buoy's movement.

By Frequency

With higher frequencies, different water depths are applicable. For example, a 600 kHz ADCP shall be suitable for water depths up to 70 meters, an ADCP operating at 300 kHz supports depths up to 110 meters, while the 75 kHz is quite suitable for far deeper waters of up to 1000 meters. It will, therefore, enable you to select the most appropriate ADCP based on the actual water depth conditions in the coastal area of Murcia.

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.