How do we measure the coastal currents of Laasqoray?

1. Where is Laasqoray?

Laasqoray is a coastal town in the northeastern part of Somalia, in between the Indian Ocean coastline, which is a mesmerizing and energetic maritime environment.

The beaches in Laasqoray areas are amazingly well decorated with sandy beaches that are extended, endless to the vision, interchanging with the rocky ones thrusting themselves into the ocean. The waters of the Indian Ocean here are warm and immense, filled with all kinds of marine life. From schools of colored fish that dart through coral reefs to several species of whales and dolphins, the marine ecosystem is full of life and wonder.

The human elements in Laasqoray speak to an ancient relationship between the community and the sea. For as long as they can remember, fishing has been a huge part of their lives and culture. The ocean is very deeply connected with the culture and heritage of the town, depicted by the traditional fishing skills, tales of voyages, and the local handicrafts, which often bear motifs related to the marine environment. Besides this, the shoreline has also experienced certain maritime trading activities for quite some time, though it has been relatively smaller in comparison with some bigger ports in the area.

2. What is the condition of the coastal currents near Laasqoray?

A number of features have very much influenced the coastal currents around Laasqoray. First of all, the pattern of large-scale ocean circulation dominance in the Indian Ocean is a major concern. The circulations of vast ocean currents, for example, like the Somali Current, which under the influence of monsoon winds and the rotation of Earth, determines whether the flow along the Somali coastline, where lies Laasqoray, shifts or not.

Another important factor involves the monsoon winds themselves. In different seasons, their direction and strength change. For example, during summer months, the southwest monsoon may push the surface waters northward along the coast, while in winter, the northeast monsoon may partially reverse the flow. This seasonal shift in wind patterns creates very large changes in the directions and speeds of coastal currents.

Tidal forces do have an effect on littoral currents. Due to the constant rise and fall of the tides, changes in the flow of water near the coast occur. While high tide may carry stronger currents and push the water further inland in some areas, low tide might expose certain parts of the seabed and change the patterns of flow close to the coast.

Furthermore, topography around Laasqoray at the seabed further modifies it. The underwater features of ridges, canyons, and sandbars may alter the direction or even break up the water flow and develop complex, specific current patterns typical only for that section of shoreline.

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

• Surface Drift Buoy Method: This is one of the traditional methods of determining the surface currents of a body of water by deploying on its surface buoys designed to drift with the currents. These buoys are generally tracked with satellite-based tracking systems or other positioning methods to derive information on the direction and speed of the surface currents. However, the level of applicability of this method is confined to the surface layer, and it may lack in providing an effective representation of currents at different depths.
• Anchor Boat Method: This involves a boat anchored at one location in coastal waters. Equipment measuring the flow of water at different depths around the area is discharged from it. Although it may give more detailed information on currents in the near vicinity of the boat than the surface drift buoy technique, it is somewhat limited in respect to large-scale area coverage and might also be affected by the movement of the boat due to waves and other disturbances.
• Acoustic Doppler Current Profiler (ADCP) Method: ADCP is an advanced and more efficient method for measuring currents. It relies on sound waves to measure the water velocity at greater depths simultaneously. It can be installed in many ways, like on boats, at the seabed in a fixed position, or attached to buoys. With its capability of providing detailed, continuous data on current profiles from the surface down to remarkable depths, it has emerged as a preferred choice for observing the coastal currents near Laasqoray.

4. How do ADCPs using the Doppler principle work?

ADCPs work on the basis of the Doppler principle. They transmit sound pulses in the water at a known frequency. As soon as these sound waves encounter moving particles in the water-like suspended sediment or small organisms-due to the Doppler effect, the frequency of the reflected sound waves changes. The change in frequency is directly related to the velocity of the water carrying those particles.

Measuring the frequency shift of reflected sound waves coming from different directions and at different depths, ADCPs can compute the multi-dimensional velocity components of the water flow, usually with a horizontal and vertical component. Normally, an ADCP flow meter operates with multiple acoustic beams to derive a more complete impression of the current structure. It will help to build the detailed current profile of how exactly water moves at the different levels along the coastline of Laasqoray.

5. What is necessary to measure currents around the Laasqoray coast of good quality?

The equipment to measure the coastal currents near Laasqoray should have a number of features for high-quality measurement. Its materials should be very reliable and capable of resisting hard marine conditions. It needs to be resistant to saltwater corrosion, the mechanical load due to waves, and temperature variations.

The size of the equipment should be small enough to facilitate easy deployment and installation in various settings, whether on boats, on the seabed, or on buoys. A lightweight design is also beneficial as it simplifies handling and transportation. Low power consumption is desirable to ensure that the equipment can operate continuously for extended periods without the need for frequent battery replacements or a large power supply source. It also boasts cost-effectiveness to allow its wide application and measurement on a large scale.

On the housing of ADCPs, a titanium alloy is greatly recommended. Titanium alloy has the strength to withstand the mechanical forces at sea. It resists seawater corrosive effects highly and is of essential use to give this instrument an extended useful life. Being less dense compared to some other metals, this makes it suitable in areas where weight could be a factor, hence fitting well for coastal current measurement devices near Laasqoray.

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

Based on the Use Purpose

• Shipborne ADCP: This is suitable when measurements are to be made while the ship is in motion. It can provide continuous data on the currents as the ship sails along the coast-for example, during scientific research voyages or during routine monitoring by naval or research vessels.
• Bottom-mounted ADCP: Suitable for long-term and stable measurements at a fixed location on the seabed. It can provide detailed information on the current patterns in a specific area over an extended period, which is useful for understanding the local hydrodynamic conditions.
• Buoy-mounted ADCP: This is very good for the measurement of surface and near-surface currents when the buoy is deployed in the coastal waters. It helps in studying the interaction between the atmosphere and the ocean surface currents.

Based on Different Frequencies:

• A 600 kHz ADCP will often be an appropriate fit for shallow coastal waters up to 70 meters in depth and can deliver reasonably accurate current measurements within such a depth range.
• Between 70 to 110 meters, a 300 kHz ADCP may be better because at such a depth one can get pretty good penetration with reliable data on the water column.
• Where the water depth is up to 1000 meters, say some deeper regions of the Indian Ocean off Laasqoray, the ideal equipment for conducting the current measurements for the full-water column is an ADCP rated at 75 kHz.
• In fact, there are several famous ADCP brands in the market, including Teledyne RDI, Nortek, and Sontek. For a high-quality, cost-effective choice, the China Sonar PandaADCP would be a good one. The PandaADCP is made of all-titanium alloy material and is durable in the marine environment, which allows it to serve excellently. Moreover, it has a very impressive cost-performance ratio. You can visit the official website here: https://china-sonar.com/.

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