How can we measure the coastal currents of Bandar Murcaayo?

1. Where is Bandar Murcaayo?

Bandar Murcaayo is a coastal city in Somalia. It lies along the coastline of the Indian Ocean, which is huge and dynamic.

The surroundings of Bandar Murcaayo host a stunning coastline with sandy beaches where the warm waters of the Indian Ocean lap up. The sea here is host to a rich and diverse marine ecosystem. It comprises a wide variety of fish species, colorful coral reefs, and other interesting sea creatures. Locals are close to the ocean, as fishing is a big part of their livelihood. This city also holds a unique cultural heritage due to its being coastal and because the sea is important to them. Some even show seafaring traditions.

2. What is the condition of the currents near the coast around Bandar Murcaayo?

Various driving forces normally drive coastal currents near Bandar Murcaayo. In detail, large-scale ocean circulation patterns in the Indian Ocean top up to their important role. Some of these include currents like the Somali Current, which influences the local current regime. The Somali Current is critically linked to the monsoon winds, which shift in seasons.

The tidal forces account for the variation in coastal currents. Due to the regular rise and fall of tides, changes take place in the speed and direction of the flow of water. Besides this, the topography underwater off the coast affects the current. Underwater features such as ridges, canyons, and shoals might well act to divert or disrupt flow in currents to create complex patterns close to shore.

Wind patterns, most especially the prevailing monsoon winds, can propel the surface waters and cause variances in current directions and speeds. For instance, the southwest monsoon is capable of shoving the water in one direction while the northeast can reverse or alter the flow.

3. How to observe the coastal water flow of Bandar Murcaayo?

• Surface Drift Buoy Method: Under this, buoys are disposed in the water that drift due to currents. Their movements can be followed via satellite-based or other positioning systems to know the direction and speed of surface currents. In any case, the approach remains limited as it deals more with the surface layer and would not be representative of the whole depth variation in currents.
• Anchor Boat Method: This involves anchoring a boat in the coastal waters and using instruments to measure water flow at various depths around the boat. While this may be more specific for the currents in the immediate vicinity of the boat, it has limitations as to area coverage and may be affected by the motions of the boat due to waves and other factors.
• ADCP Method: ADCP current meter is a sophisticated and quick way of measurement of currents. It uses sound waves to measure the velocity of water at more than one depth simultaneously. It can be deployed in different ways: on boats, on the seabed (bottom-mounted), or attached to buoys. Its capabilities further extend to yield detailed and continuous data on the present profile from the surface down to great depth; this makes it preferred for observing coastal currents near Bandar Murcaayo.

4. How do Doppler Principle Using ADCPs work?

They operate on the principle of the Doppler effect. ADCPs send sound pulses into the water at a known frequency. When these transmitted sound waves interact with moving particles in the water-such as suspended sediment and/or small organisms-the frequency of the reflected sound waves is shifted by the Doppler effect. The frequency shift will be proportional to the velocity of the water carrying those particles.

By measuring the frequency shift of the reflected sound waves coming from different directions and at various depths, ADCPs can calculate multi-dimensional velocity components of water flow, normally horizontal and vertical. An ADCP current profiler uses multiple acoustic beams to gain a comprehensive understanding of current structure. This allows the construction of detailed current profiles showing how the water is moving at different depths along the Bandar Murcaayo coast.

5. What is needed to realize high-quality measurement of Bandar Murcaayo coastal currents?

To perform high-quality measurement of coastal currents around Bandar Murcaayo, equipment must be of a specific character. The materials should be reliable to sustain the harsh conditions of the sea. It has to be resistant to the saltwater's corrosive action, the mechanical stress exerted by waves, and temperature variations.

The equipment size must be small, so as to be easily deployed and installed in different configurations on boats, seabed, and buoys; a light design is also useful for easy handling and transportation. Low power consumption is of interest for very long-term operation with no frequent need for battery exchange or large-scale power supply. Cost-effectiveness is also called for in view of large-scale measurements.

On matters of the ADCPs casings, a good material should be made from titanium alloy. It has a high strength that allows it to withstand mechanical forces in the ocean environment. Corrosion from sea water is highly resisted and therefore it makes the equipment have a long life span. Compared to other metals, its density is relatively low; thus, it would also serve best where the weight is concerned according to the demands for the device under measurement along coasts.

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

Based on the Use Purpose

• Ship-borne ADCP: It is suitable where measurements are to be made while the ship is in motion. This will continuously give data on the currents as it sails along a coastline. It is useful on research vessels and naval ships during surveys.
• Bottom-mounted ADCP: Suitable for long-term and stable measurement from the fixed location in the seabed; it gives enough detail of current patterns over long periods in a specific area, which is useful for depicting local hydro-dynamic conditions
• Buoy-mounted ADCP: Useful for measuring surface and near-surface currents once the buoy is deployed in the coastal waters. It helps study the interaction between the atmosphere and the ocean surface currents.

Based on Different Frequencies

• For fairly shallow coastal waters to a depth of about 70m, a 600kHz ADCP is a good choice because current measurements are rather accurate at this range. In waters ranging between 70 to 110 meters deep, an ADCP flow meter with 300kHz frequency would be more adequate since it would be able to get through the water column to acquire reliable data effectively.
• In deeper waters of up to 1000m, such as those found in the Indian Ocean near Bandar Murcaayo, a 75kHz ADCP will be best to measure currents throughout the water column.
• There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, for those looking for a cost-effective option, the China Sonar PandaADCP is a good alternative. It's made of all-titanium alloy material and offers 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.