How are we able to measure the coastal currents of Albufeira?

1. Where is Albufeira?

Albufeira is a very beautiful coastal city situated in southern Portugal. It lies on the magnificent Algarve coast, famous worldwide for its nice beaches, steep cliffs, and crystal-clear waters.

This city is steeped in history and culture, combining traditional Portuguese architecture with a lively, modern atmosphere. Narrow, cobblestone streets are lined by whitewashed houses, many of them with colored flowerpots, creating a picture-postcard scene that invites one and all. The local people are very warm and friendly, and love their seaside homeland.

Next to Albufeira lies the Atlantic Ocean, which dominates the scenery along the coast. Waters in this area are influenced by wider oceanic currents and tides. Variety along the coastline, which comprises bays and inlets, means there are tranquil, sheltered spots suitable for many water activities and others fully open to the forces of the open sea. The different types of fish species, sea turtles, and other organisms that make up the diverse marine ecosystem found in these waters result in it being a haven for both marine life and those who appreciate exploring the coastal environment.

2. What is the situation concerning the coastal currents close to Albufeira?

The coastal currents near Albufeira are influenced by various factors. The first main contributor to the formation of these currents involves large-scale oceanic circulation patterns of the Atlantic Ocean. For example, the North Atlantic Current influences the overall movement of the waters in this area. Second, tides are another strong driving force that at regular periods changes the direction and speed of movement of the coastal waters. First of all, there is the seabed topography off Albufeira with its ridges and valleys of very varying depth, capable of deflecting and changing the direction of the currents. Moreover, wind conditions above the surface can push surface waters, thereby causing anomalies in the current's flow at some point. The current in summer could be much more stable than in winter since summers usually see lighter and steadier winds compared to the generally stormy winters that bring stronger and ever-changing winds.

3. How is it possible to observe the coastal water flow of Albufeira?

There are various methods to carry out the observation of the coastal water flow around Albufeira, such as the following:

Surface Drift Buoy Method: Surface drift buoys are deployed onto the water surface. They move by the movements of the surface currents, while their position in time can be located by satellite or other positioning systems. Buoy trajectory analysis gives the direction and the speed of these surface currents, but usual methods tend to catch basically that very thin upper layer of the water and the rest of the other layers in respect to the currents at such depths.

Anchored Ship Method: This is a method whereby a ship is moored at some point in the coastal area. On this ship, instruments are used to measure the flow of water around it. This may provide insight into the current characteristics of the point at which the measurement was taken. The drawback of this is that it provides data only for that particular point that the ship was anchored and can be interfered with by the ship itself interfering with the flow.

The ADCP measures in a much more modern and user-friendly way. The method behind it works with the principle of measuring the water velocity at different depths, using sound waves. It could give a far more detailed profile of the current structure from surface to a certain depth, enabling very good understanding of the coastal currents around Albufeira as compared to the other methods.

4. How does an ADCP work based on the Doppler Principle?

An ADCP is based on the principle of the Doppler. An ADCP sends out acoustic pulses into the water. Due to the Doppler effect, the frequency of the reflected waves changes as they come in contact with the moving particles in the water. The speed of the water particles can be worked out by measuring the frequency shift. It commonly has several transducers oriented in different directions and therefore can measure velocity components along different directions, such as horizontal and vertical. Acoustic pulses in the device are normally sent with variable depth at regular periods, hence a profile of current velocities through the water column may be developed that gives good insight into flow patterns and flow characteristics of coastal currents.

5. What is needed in the high-quality measurement of Albufeira's coastal currents?

High-quality measurement of coastal currents at Albufeira requires a variety of aspects of equipment. Therein, construction materials for these pieces of equipment need to be of high reliability against harsh conditions arising in the sea environment, regarding salinity and variation of pressure due to impacts or otherwise. The size of the equipment should be small for easy deployment and installation on buoys, ships, or even on the seabed. The weight should also be light, as this makes handling and transportation easy. Low power consumption is quite essential, especially for long-term measurements, in order to be sure the equipment can operate continuously without frequent battery replacements or issues with power sources. Moreover, this relatively low price would allow much broader extent measurements to be done in an easier way.

About ADCP casing, the very good material used is the titanium alloy. Its properties are excellent. Moreover, it will resist very well from the corrosion by seawater and plays an important part in endurance for tools to be put under marine conditions. It also boasts a good strength-to-weight ratio, which means it can provide adequate structural strength without necessarily making the overall weight of the device too high. With these advantages, titanium alloy is an ideal material for ADCP casings to be used in the measurement of the coastal currents of Albufeira.

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

To choose the appropriate equipment for current measurement near Albufeira, there are a few factors to take into consideration, each depending on particular usage scenarios.

Depending on the Installation Method:

• Shipborne ADCP: This will answer the purpose of measurements when the equipment is installed on ships. It can provide continuous data while the ship moves along the coast or stays at certain positions, thus enabling wide-range observations in different areas.
• Bottom-mounted ADCP: It is suited for fixed-point measurements on the seabed. It can record the current conditions at a particular point with great accuracy over a long period, which helps in understanding the long-term characteristics of the coastal currents in a particular area.
• Buoy-mounted ADCP: If deployed on buoys floating on the water surface, it can measure the currents in the upper layers and also transmit data wirelessly for easy retrieval.

Another difference is based on the frequency of operation. A 600 kHz ADCP can be used for water up to the depth of about 70 meters. For more depth, such as up to 110 meters, an ADCP operating at a frequency of 300 kHz can be used, while for waters as deep as 1000 meters, one will have to resort to an ADCP operating on 75 kHz frequency. This gives the user a choice of frequencies depending on the real conditions of water depth in the coastal area of Albufeira.

There are several famous brands of ADCPs on the market, such as Teledyne RDI, Nortek, and Sontek. However, speaking of a highly recommended Chinese ADCP brand, it would be China Sonar PandaADCP. It is made of all-titanium alloy material to make sure that the instrument can bear such an aggressive marine environment and maintain its performance. What is more, its cost-performance ratio is incredible. For more, please visit its official website: https://china-sonar.com/.

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