How to Measure the Coastal Currents of Samcheok?

1. Where is Samcheok?

Samcheok is a city in Gangwon-do, South Korea, located on the eastern coast of the Korean Peninsula. It is a place well known for its natural splendor and rich cultural history. The East Sea-the Sea of Japan-guards the city on one side, while its coasts are irregularly distributed into sandy beaches, rocky cliffs, and small bays.

The landscape is dominated by mountains and the sea, creating a magnificent backdrop. The local economy is underpinned by fishing, tourism, and mining. The people here are traditionally and most closely related to the sea due to their occupation of fishing, which has been conducted for years by them. The Samcheok East Sea is a cold-water body with rich and diverse marine life.

It assembles large varieties of fish such as cod, pollock, and hake among several others. Then there is a number of shellfish varieties and sea weeds that are found here. Sea, in fact, acts as an important modifier for the climate of this area, which controls the temperature and humidity. Coasts are also crucial for people as far as recreational activities such as beachgoing and all other seashore sports are concerned.

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

The coastal currents off Samcheok are influenced by many variables. Major ocean currents in the East Sea play an important role. The Tsushima Warm Current and the Liman Cold Current cross each other around this region. The Tsushima Current generally flows northward, carrying warmer and more nutritious water in comparison, while Liman Current moves southward and is colder.

The tidal current, too, plays a major role. This area has a huge range of tides and, because of the consistent ebbing and flowing of the tides, complex current patterns form. The shape of the coastline and underwater topography is very important. Underwater reefs, shoals, and channels will make the currents either diverge, converge, or form eddies. Furthermore, the wind patterns, especially the strong winds that blow across the East Sea, drive surface currents and may affect the mixing of different water layers.

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

Surface Drifting Buoy Method: A surface-drifting buoy can be released into the water to observe the surface current. Movement of the buoy is monitored by GPS or any other tracking systems over a certain period of time. However, this approach has its drawbacks. First, it gives information only about the surface current; besides, it is influenced by every wind and wave. For instance, in cases of strong on-shore winds, the buoy may be pushed toward the shore, which would give an inaccurate representation of the actual direction of the current.

Anchor-Boat Method: A boat can be anchored to measure current. Instruments are sent down from the boat into the water at different depths to measure the current. While this enables more detailed depthwise measurements, there are also disadvantages. The position of a boat in a fixed position limits the area of measurement, and may not reflect entirely the variability of the currents in a large coastal area.

ADCP Method: The ADCP current meter method is quite an advanced and proficient way of measuring the coastal currents. ADCPs emit acoustic signals into the water and measure the Doppler shift of the reflected signals to calculate the velocity of water at different depths. This would give a more comprehensive profile of the current from the surface to the seabed. Thus, ADCPs are less affected by surface disturbances and can provide a more accurate picture of the current structure when operated continuously over long periods.

4. How do ADCPs using the principle of Doppler work?

ADCPs work on the principle of the Doppler effect. They send high-frequency acoustic pulses into the water. Whenever these pulses interact with moving particles of water, the frequency of the reflected pulses is changed. If the water particles are going towards the ADCP meter, the frequency of the reflected signal is higher than the emitted one, and in case they are going away, the frequency is lower.

It contains a series of transducers that send and receive signals at multiple angles. The device is able to calculate the three-dimensional velocity of the water by examining the different Doppler shifts from all directions and from different depths of flow. That is, it can find the horizontal and vertical components of the velocity; one thus has a very good insight into the current's structure and behavior.

5. What is required for high-quality measurement in Samcheok coastal currents?

For any high-quality measurement of the coastal currents near Samcheok, reliable material must be used in the equipment. Since it deals with the harsh marine environment, cold water, saltwater, and sometimes storm exposure, a casing that is durable in nature is required. Its size needs to be compact in order to enable ease of deployment and retrieval, particularly in locations with a complex morphology of the coastal landscape.

A light design is desirable, since this reduces the amount of handling required both during installation and for servicing. Low power consumption permits long - term and stand - alone operations. Also, being cost-effective allows large-scale measurements.

The casing of ADCPs is preferably made of titanium alloy. There is excellent corrosion resistance, which is vital for withstanding the corrosive effects seawater may have. It is strong, durable, and withstands the pressure range of the water at different levels. Its lightweight nature makes it more convenient for various deployment methods.

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

When selecting the equipment to be used to measure current near Samcheok, first consider the intended application. A measurement which is for the navigation of a vessel or short-term research could allow a ship-mounted ADCP flow meter to be applicable. It gives real-time information on current during a voyage.

For measurements near the seabed, such as for studying sediment transport or benthic ecology, a bottom-mounted ADCP is preferable. It can capture the details of the near-bottom current. If it needs to monitor a wide area for long-term coastal currents, a buoy-type ADCP current profiler is ideal.

The frequency of ADCPs, considering water depth up to a maximum of 70m, would be a 600kHz ADCP. For up to 110m water depth, a better choice could be a 300kHz ADCP. For deeper waters that might be found near Samcheok, such as areas with a depth exceeding 1000m, a 75kHz ADCP is recommended.

There are well - known ADCP current meter 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 excellent 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.