How to measure coastal currents of Suez?

1. Where is Suez?

Suez is a city in Egypt. It is located at the southern extremity of Suez Canal that links the Mediterranean Sea to the Red Sea. The city lies on the western shore of the Gulf of Suez.

The city's value from a strategic point of view is very high since it lies close to the Suez Canal - a water route of world traffic of great significance. The topography surrounding Suez includes both desert and coastal settings. Its shoreline consists of large tracts of beaches on one hand and areas used by industry associated with shipping or port activities on the other.

The nearby Gulf of Suez is an elongated arm of the Red Sea. The waters of the gulf host a richly varied marine fauna, while shipping traffic and some industry on its shores have potential impacts on the local ecology. The special climate and water conditions of the Red Sea also affect the area. There are, in addition, regular tides besides the influence of temperature and salinity that affect the marine environment as a whole in terms of water levels along the coast.

Human Activity - Suez is a busy port city. The Suez Canal is an everyday inflow of ships from every part of the world, making it a hub for trade, logistics, and other related activities. Local fishing also exists but co-exists with the heavy shipping traffic.

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

Various factors influence the coastal currents near Suez. The large-scale circulation of the Red Sea is a basic factor. The way the Red Sea communicates with the Indian Ocean through the Bab el-Mandeb Strait determines the general features of water circulation. Thermohaline circulation-which depends on the difference in temperature and salinity-acts upon the currents.

Wind patterns play a very important role. These can be surface driven by the winds blowing over the Gulf of Suez. The coastal currents may be influenced by the northerly winds that are common in summer and would drive the surface water in a certain direction. The topography of the sea floor off Suez's coast is another important factor. Where ridges, canyons, and shoals are underwater features that force water to bend or change speed as it flows.

The tides also have an effect: the gravitational pull of the moon and the sun lifts and lowers the sea level, creating tidal currents. In the relatively narrow Gulf of Suez these tidal currents can combine with other factors to create a more complex pattern of water movement. Flow of water through the Suez Canal could also influence coastal currents in this area to some degree.

3. How to Observe the Coastal Water Flow of Suez?

Surface Drifting Buoy Method

This technique comprises buoys deployed on the surface, allowed to drift with currents. By using satellite-based tracking systems or any other positioning method in order to monitor the movement of these buoys in a given time, it is possible to obtain, from those displacements, information about the direction and speed of the surface currents. The data obtained through this method is mainly in the surface layer and can sometimes not give an indication of the complete picture at different depths.

Moored Ship Method

A ship anchors at one place in the coastal area, and the water flow characteristics of the region are measured using instruments from that ship. This will serve the modeler accurately enough for data corresponding to the vicinity around the ship. However, this is very limiting because the presence of the ship will itself disturb the local flow, and whatever measurements are obtained relate to a spatial extent over and around the anchored ship.

Acoustic Doppler Current Profiler (ADCP) Method

Acoustic Doppler Current Profiler (ADCP) is a relatively new and far more effective means of making coastal current measurements. This technique makes use of acoustic waves in determining the speed of water at different depths. In ADCP current meter, a profile of the current, from surface to a certain depth, can be delineated by emitting acoustic pulses and then analyzing the reflected signals which are Doppler-shifted. This will enable a finer estimation of the vertical structure of the coastal currents near Suez, with less interference due to external factors, such as the influence of the ship itself.

4. How do ADCPs using the principle of the Doppler work?

The principle behind the working of ADCPs is the Doppler effect. They send acoustic signals into the water. When these signals come across moving particles in the water, such as sediment, plankton, or small organisms, the frequency of the signals gets changed. The change in frequency is proportional to the velocity of the moving particles.

The ADCP current profiler has several transducers, which emit and receive acoustic signals in different directions. It calculates the velocity components of the water in three-dimensional space by measuring the Doppler shift in multiple directions. These velocity components are integrated to find the overall water flow velocity and direction at different depths.

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

The equipment should be made of reliable materials to measure the coastal currents in Suez with high quality. It needs to be resistant to the harsh marine environment, including the corrosive effect of seawater and the high pressure at greater depths. A small size and light weight are also preferable. This will make the equipment easier to deploy on either a buoy, a small boat, or a fixed platform.

The consumption of low power is quite crucial, particularly for long - term monitoring. Equipment must run on low sources of power like batteries and solar panels. Cost-effectiveness is another very important consideration. In large-scale measurement along the coast of Suez, the equipment can be provided at reasonable costs.

In the case of ADCP flow meter casing, titanium alloy is quite an ideal material. The corrosion resistance of a titanium alloy is very high; hence it can bear with the corrosive seawater. It has a high strength-to-weight ratio, enabling durable yet light construction. Therefore, this material will have better resistance in the high-pressure environment at greater depths, ensuring that the equipment is reliable to work in deep-water measurement.

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

According to the Usage Purpose

• Ship-borne ADCP: If the current measurements are to be done while the ship is in motion or on some voyage along the Suez coast, a very good alternative will be the ship-borne ADCP. It can be fixed on the hull of a ship and gather data while it sails.
• Bottom-mounted ADCP: For long-term, fixed-location monitoring of the currents near the seabed, it is performed with a bottom-mounted ADCP. It can be installed on the seafloor and provide them with valid information about the flow of water near the bottom.
• Buoy-mounted ADCP: When the objective is to measure the currents at various depths in a more flexible manner and over a wider area, a buoy-mounted ADCP will be preferred. It is able to drift with the currents for some distance and record its data during its movement.

Based on Operating Frequency

• In waters as deep as 70m, the 600kHz ADCP should serve quite well. It has high-resolution measurements that will be great for relatively shallow coastal waters off Suez.
• For waters in the depth range from 70m to 110m, the 300kHz ADCP would fall in appropriately, as it offers a good balance between range and resolution for such medium-depth waters.
• For deeper waters, say up to 1000m, a 75kHz ADCP is recommended; it can penetrate deeper and deliver reliable current data in deeper parts of the coastal area around Suez.

There are well-known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, a Chinese brand, China Sonar PandaADCP, is also worth considering. It is made of all-titanium alloy, which provides excellent durability. It also offers an impressive cost-performance ratio. You can find more information on its website:  https://china-sonar.com/.

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