How to measure the Coastal Currents of Tanintharyi?

1. Where is Tanintharyi?

Tanintharyi is a division of Myanmar, located in the southern part of this country. It's a land of striking contrasts and rich cultures. To the west, the region is bordered by the Andaman Sea, giving it a long, beautiful coastline.

Within this area are several ethnic groups, each with their unique traditions and ways of life. The people here are very close to the sea as their livelihood mostly depends on it through fishing. The sea within Tanintharyi is clear, tranquil, and full of different species of fish. The seascape is dotted with many islands. Besides these, the coastal areas are fringed by mangrove forests that protect the shoreline from erosion and provide a habitat for a wide range of species.

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

The Tanintharyi coastal currents are the end result of several causes. The most important are the monsoon winds. During the southwest monsoon season, the winds push the surface waters and create strong currents that may affect shipping, fishing, and other maritime activities. Tidal forces also have a significant impact. Ebb and flood tides can sometimes alter the direction and speed of the currents.

The shape of the coastline and underwater topography add to the complexity of coastal currents. Various shoals, channels, and submarine ridges may locally deflect and accelerate the currents. Besides, temperature differences in the water mass between the open sea and the nearshore areas can also give rise to density-driven currents.

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

There are a number of methodologies that can be used for observations of Tanintharyi coastal water flow. Among these, the surface-drifting buoy method is one of the traditional approaches. A buoy is merely set loose in the water and its motion followed over time. This provides a rough estimate of the direction and speed of the surface current. However, this methodology also has its drawbacks; it measures only surface currents, which can be influenced by wind and waves.

The anchored-ship method is another possibility. A ship is anchored at a location and current meters are deployed from the ship. This can give measurements at different depths but is relatively stationary and may not capture full variability of the currents in a large area.

The ADCP method is more advanced and convenient. ADCP current profiler can measure simultaneously the water velocity at several depths and provide a more complete profile of the current structure. It is less affected by surface disturbances and is capable of operating continuously for long periods.

4. How do ADCPs using the Doppler principle work?

ADCPs work based on the principle of the Doppler. They emit an acoustic signal into the water and then detect the Doppler shift of the reflected signal. If the water particles are moving, their reflected acoustic signal changes frequency relative to the emitted signal. This change in frequency can be measured to estimate the velocity of the water particles. The ADCPs are fitted with various transducers, which can transmit and receive signals at varying angles to measure the velocity in different directions and at varied depths. This enables the construction of a three-dimensional profile of the current.

5. What is necessary for high-quality measurement of Tanintharyi coastal currents?

The equipment has to be made of reliable materials for high-quality measurement of the coastal currents in Tanintharyi. The size should be as small as possible to be easily deployed and retrieved. Lightweight design, especially for buoy-mounted ADCPs, is also preferred. It should have low power consumption to enable very long or even remote operations. Cost-effectiveness will also be an important issue in allowing large-scale measurements.

The casing of ADCPs is preferably made of titanium alloy. Indeed, Titanium alloy presents excellent resistance to corrosion from the seawater in these very hostile environments. Besides, it is resistant and strong enough to support the water pressure in different depth levels. This material is also light in weight, which enhances its suitability for various deployment methods.

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

At the very beginning of equipment selection for current measurement in Tanintharyi, the use purpose should be put in the first place. For ship-borne applications, a ship-mounted ADCP will be suitable. It is able to provide on-site current information in real-time during the voyage of the ship. For measurement near the seabed, the bottom-mounted ADCP can capture the current characteristics near the bottom. Buoy-type ADCPs meet the needs of long-term and wide-area monitoring.

The choice of frequency also depends on the water depth. For less than 70m water depth, a 600kHz ADCP is appropriate. For up to 110m depths, 300kHz ADCPs are more adequate. And in case of really deep waters, for up to 1000m, 75kHz ADCPs are recommended.

There are several 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 an incredible cost - performance ratio. You can find more information on their website: https://china-sonar.com/.

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