How do we measure Klang Coastal Currents?

1. Where is Klang?

Klang is a town in the state of Selangor, Malaysia. It is on the west coast of the Malay Peninsula and near the Strait of Malacca. Klang has a rich history as a port town and was once a major center for the tin and rubber trade.

This city is connected with other parts of Malaysia by roads and railways. The people are a good blend of Malays, Chinese, and Indians, which is very diversified. This is depicted in the culture, food, and architecture of the place.

The Strait of Malacca, on the west, is one of the most crucial waterways for international shipping. The coasts of Klang comprise a mix of industrial ports and natural habitats. Partial areas of this region contain mangrove forests, which are an important constituent in the coastal ecosystem. These mangroves serve as habitats for a wide variety of fish, crustaceans, and birds. The waters of the strait host plankton, huge ships crossing the busy shipping lanes, and every size and type of marine organism in between.

2. What about the situation of the coastal currents around Klang?

These coastal currents are influenced by a combination of factors, one of which is tidal currents. Tides in the Strait of Malacca are semi-diurnal and are influenced by the gravitational pull both from the moon and the sun. It produces two high tides and two low tides each day. These tidal currents are very strong and, especially, nearshore or where there is any constricted flow of water.

Monsoon winds also have a major impact. The southwest monsoon, which generally lasts from May to September, provides strong winds that drive the surface currents in a particular direction. The northeast monsoon, between November and March, changes the wind direction and definitely affects the direction and speed of coastal currents. The interaction between the tidal and monsoon - driven currents creates a complex and variable flow pattern.

The coastal currents may differ depending on the local bathymetry, like ridges, channels, and shoals. On the other hand, the currents can also, to a limited extent, be influenced by industrial ports and the discharge of various substances from these. Besides, the inflow of freshwater from nearby rivers and canals forms density differences affecting the current patterns.

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

There are many methods of observing the coastal water flow in Klang. The common method for observing this is by using the surface drifting buoy technique. Buoys are set into the water and fitted with GPS or some other devices used for tracing. While the buoys are taken away by the currents, after a specific amount of time, their movement is monitored to ascertain the direction and speed of the surface currents.

In the anchored ship method, a ship is anchored at a certain place, and the flow of water at different depths is measured using current-measuring instruments. This also has its drawbacks. The ship is subjected to waves and winds which might give erroneous measurements. This is also not an efficient way of covering a vast area.

The ADCP method is an advanced, efficient way of measuring the flow of water in the coast. ADCP current profiler can measure the velocity profile over a wide range in the current depths. They emit sound waves into the water and analyze the Doppler shift that the reflected waves undergo. This gives detailed knowledge about current structure right from the surface down to the seabed.

4. How do ADCPs using the Doppler Principle Work?

Acoustic Doppler Current Profiler (ADCP) work on the principle of the Doppler effect. They send acoustic pulses or simply sound waves into the water. These sound waves scatter off the particles in water such as sediment, plankton, and other small particles. When those sound waves bounce off these particles and are reflected back to the ADCP, the frequency of the reflected waves has changed because something called the Doppler effect has taken place.

While the particles are moving towards the ADCP flow meter, then the frequency of the reflected wave is higher than that originally emitted. If the particles were moving away from the ADCP meter, the frequency of the reflected wave would be lower. Given a precise measurement of this frequency shift, the velocity of particles can be determined by the ADCP. Because the particles are in motion due to the water current, the velocity of the particles computed would be equal to the water current velocity.

It also allows ADCP profiler to transmit sound pulses in various directions to measure the three-dimensional current velocity in space and at different depths. For example, they may record in a vertical profile-the current velocity at different intervals from the surface to the seabed, in order to give a complete picture of the current structure.

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

The equipment should, therefore, be made of materials that can assure reliable measurement of the coastal currents in Klang. The marine environment is quite harsh, considering the corrosion caused by saltwater and possible physical impacts from waves or debris; hence, a durable casing is quite important.

The size of the equipment should be small enough to make its deployment quite easy, particularly in those areas where access is poor, such as in small boats or shallow coastal waters. A lightweight design is also quite useful, because this allows more convenience in handling and installation.

Long-term measurements need low power consumption. As a whole, the cost of the instrument should also be as low as possible to allow for large-scale measurement capabilities. In the case of ADCPs, the casing is preferred to be made of a titanium alloy. This is because it has good resistance to corrosion, important in the marine environment of Klang, able to bear the corrosive effect of saltwater for a great length of time. Besides this, it is strong and has a high strength-to-weight ratio; hence, a durable, yet lightweight structure that will be able to protect the internal components of the ADCP.

6. Choosing the Correct Equipment for Current Measurement?

The basic usage is first to be considered in choosing the right equipment for the measurement of current in Klang. A ship-borne ADCP would do satisfactorily for measurements from a moving vessel. It can give real current data in a moving ship.

A bottom - mounted ADCP is an adequate solution for point measurements close to the seabed. The instrument can measure the point current continuously.

For area measurements, a buoy - type ADCP is appropriate for area-wide measurements that do not have to take place at a certain depth.

Where frequency choice is concerned, a 600kHz ADCP should be good to go up to water depths of 70m. At a depth ranging from 70-110m, a 300kHz ADCP works better. For very deep waters, say 1000m, a 75kHz ADCP would do.

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 material and offers a great cost - performance ratio. You can find more information about it on the website: https://china-sonar.com/.

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