How to measure coastal currents of Quseer?

1. Where is Quseer?

Quseer or Al - Qusayr is a coastal city in Egypt, lying on the Red Sea. The area combines the harsh arid deserts with the amazing expansive view of the Red Sea.

The shoreline of the city varies with stretches of sandy beaches combined with stretches where the shore is rocky. The waters of the Red Sea off Quseer are teeming with life. This is one area hosting coral reefs, hence creating an almost incredible ecosystem in the water. Such reefs offer a habitat to a wide range of fish species, small and colorful reef-dwellers, plus large pelagic fish. Other marine organisms include sea turtles, which are quite commonly seen along these shores.

It is a well-recognized port city in terms of human activities. For a long period, Quseer has developed maritime trade and transportation. A wide range of goods and commodities pass through this port, contributing a great deal to the local and regional economy. Fishing is another key aspect of the local economy, where local fishermen have depended for long on the rich marine resources in the Red Sea. Tourism also develops, though still slowly, as more and more people have been discovering the natural beauty of the area--with its opportunities for diving, snorkeling, and other water-based activities.

The Red Sea, in which Quseer is situated, is a semi-enclosed sea. It includes larger-scale patterns of the Red Sea, including inflow of water from the Indian Ocean via the Bab-el-Mandeb Strait. Water circulation within this area also takes into account the shapes and configurations of the coastline, benthic topography, including features like reefs and shoals, affecting movement of waters and, by that, the coastal currents.

2. What is the condition of the coastal currents off Quseer?

Many aspects control the coastal currents around Quseer. The large-scale circulation of the Red Sea is a basic determinant. The general flow patterns that affect the coastal currents depend upon the inflowing water from the Indian Ocean through the Bab-el-Mandeb Strait, together with thermohaline circulation, which is driven by differences in temperature and salinity.

Wind plays a crucial role. The winds that blow across the Red Sea can drive the surface currents; for example, during different seasons, the directions and strengths can change, in turn causing the surface water to go in a specific direction and further strengthen or modify the existing current pattern. The important factor is, however, the topography of the seafloor near Quseer's coast. These features of underwater ridges, canyons, and shoals bend the water in a different direction to its flow.

The tides, resulting from the gravitational pull of the moon and sun, will also play an important determining role. In coastlines surrounding Quseer, especially in bays and inlets, tidal currents may be very strong. Along with other factors, the tidal currents will result in a complex, dynamic pattern of water movement.

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

Surface Drifting Buoy Method

It involves the use of buoys at the surface that are free to drift according to currents. Using satellite-based tracking systems or any other positioning technique, it is easy to know in which direction the buoy changes its position with time and at what speed. The drawback of this technique is that it can provide data regarding the upper layer, but it's very difficult to detect the currents at different levels.

Moored Ship Method

In this method, a ship is anchored in some position in the coastal area. The instruments on the ship measure the characteristics of water flow in the surroundings. Although this can give quite accurate data for the area around the ship, it has obvious limitations: the presence of the ship can disturb the local flow, and the spatial coverage is limited to the neighborhood of the anchored ship.

Acoustic Doppler Current Profiler Method

ADCP is more advanced and efficient in measuring coastal currents. Acoustic waves are used to measure the velocity of water at different depths. By emitting acoustic pulses and analyzing the Doppler-shifted reflected signals, ADCP can give a very accurate profile of the current right from the surface to a certain depth. It provides an indication of the detailed structure of the vertical current structure off Quseer and has much less signal contamination by other effects outside-for instance, that caused by the ship itself.

4. How does the Doppler Principle Work in ADCPs?

ADCPs work on the principle of the Doppler effect. They send acoustic signals into the water. When these signals meet the moving particles in the water-sediments, plankton, or small organisms-the frequency of the reflected signals changes. The change in frequency is proportional to the velocity of the moving particles.

The ADCP is fitted with a number of transducers that transmit and receive acoustic signals in multiple directions. By making the Doppler shift measurements in multiple directions, it computes the three-dimensional velocity components of water. These velocity components are integrated to provide the overall flow velocity and direction of water at different depths.

5. What's required for high-quality measurement of Quseer coastal currents?

It goes that high-quality measurement in Quseer should be made out of reliable material with the ability to handle the harsh marine environment, the corrosive action of seawater, and a high pressure resulting in a bigger depth. Also, it shall have a smaller size and less weight for the convenience of carrying and deploying with a buoy or small boat and fixed platform.

Low power consumption is the most important aspect, mainly for long-term monitoring. Moreover, the equipment has to be able to operate on very limited power sources, such as batteries or solar panels. The cost of equipment must be as low as possible to enable large-scale measurements along the coast of Quseer.

Speaking of the casing, ADCP, the best material could be titanium alloy. It has high corrosion resistance, which will be very important in fighting against corrosive seawater. The strength-to-weight ratio is very high, enabling a lighter yet durable design. This material can better withstand the high-pressure environment at greater depths, ensuring the reliability of the equipment during deep-water measurements.

6. Selection of Appropriate Equipment for Measurement of Current

Based on Purpose of Use

• Ship-borne ADCP: If the plan is to measure the currents during any movement of the ship or during a specific voyage along the Quseer coast, then a ship-borne ADCP is the suitable option. It can be fitted on the hull of the ship and will observe data as the ship sails.
• Bottom-mounted ADCP: A bottom-mounted ADCP would be used for long-term, fixed-location monitoring of the currents near the seabed. They could easily and firmly be placed right on the bottom of the ocean to provide accurate details concerning water flow within proximity to the bottom.
• Buoy-mounted ADCP: When the aim is to measure currents at different depths in a more flexible way and over a wider area, the buoy-mounted ADCP should be used. It can drift slightly with the currents while collecting data during its movement.

Based on Operating Frequencies

• Water depth up to 70m: A 600kHz ADCP will be quite adequate. It gives high-resolution measurements suitable for the relatively shallow coastal waters near Quseer. -Water depth between 70 to 110m: A more appropriate choice will be 300kHz ADCP. It offers a balance between the measurement range and accuracy for medium-depth waters.
• For deeper waters, up to 1000m, a 75kHz ADCP is recommended. This can penetrate to greater depths and give reliable current data in the deeper parts of the coastal area around Quseer.

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.