How can we estimate the coastal currents of Yantai?

1. Where is Yantai?

Yantai is the main coastal city in Shandong Province, China. It nestles comfortably on the north shore of the Shandong Peninsula, with the Bohai Sea and Yellow Sea to its north, offering beautiful bays, long sandy beaches, and a pleasant climate.

The Yantai climate is a warm-temperate monsoon climate. Winters are mild, and quite warm summers. The sea breeze regulates the temperature, therefore it is very pleasant. The amount of rainfall in this region is moderate, which allows for its use by a wide variety of vegetation, from fruit orchards to coastal forests.

Yantai had very rich maritime history. Many of its numerous harbors have long been outstanding facilities for trade and fishing throughout a number of decades. The sea deeply impregnates in the local culture, in traditional fishing festivals, and variegated types of seafood cuisines.

The Bohai Sea and the Yellow Sea, the waters adjacent to Yantai, play a very important role in its economy and ecology. In general, the topography varies from shallow coastal waters to a deeper offshore area around Yantai. River runoff, tidal action, and oceanic currents are some of the forces that influence the character of these waters.

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

Many factors affect the coastal currents around Yantai. First, there is the influence of a monsoon climate. During summer, the southeast monsoon may push the surface waters and, therefore, dictate the direction and strength of the coastal currents. The wind pushes the water in a given pattern that can be followed to affect shipping, fishing, and other marine activities. During winter, the Northwest Monsoon changes the directions and speeds of the currents.

The topography of the sea floor would, therefore, also play an important role. It may be expected that ridges, troughs, and shoals underwater can result in different behaviors of currents. Generally speaking, shallow areas tend to develop slower-moving currents, while deeper regions-with complicated structures of the seabed topography-can have stronger and more variable flows. At places, there can be a retardation near the shoals due to shallow depth, while in troughs, the current can be more intense and may have a complex circulation pattern.

Another important factor could be tides. The regular rise and fall of tides in Bohai Sea and Yellow Sea can cause considerable tidal currents. These tidal currents are quite strong near estuaries and narrow channels. They play an important role in sediment transportation, nutrients, and marine life. Moreover, the tidal currents participate in coastal erosion and deposition; this influences further coastline morphology and the distribution of marine life.

Besides, the interaction with more large-scale ocean currents from the Bohai Sea, the Yellow Sea, and other adjacent regions could also change the coastal currents near Yantai. These oceanic currents can introduce water masses of different temperatures and salinities, further affecting the local current dynamics. For instance, intrusion of warmer or colder water masses may raise or lower the temperature in the coastal waters and thus have an impact on the local marine ecosystems and weather patterns.

3. How to Observe Yantai Coastal Water Flow?

Precision measurement of the coastal current in Yantai is quite necessary in many fields such as ocean safety, fisheries, and coastal defense. Traditional means of observation in coastal water flow mainly rely on buoy and current meter observation. These observation methods are used for quite a long time with relatively limited accuracy and coverage.

Acoustic Doppler Current Profilers present an improved and more practical method of measurement when it comes to coastal currents. In flowing water, ADCP profiler are used to measure the velocity with the aid of the Doppler principle. The measured velocity is utilized for developing current profiles.

3.1 Working of Acoustic Doppler Current Profiler(ADCP): The Doppler Principle

ADCP meter emit sound waves into the water. The interaction among these emitted sound waves and moving particles Anything ranging from suspended sediments to small organisms results in the variation in frequency of the reflected sound waves due to the motion of the particles. The resulting frequency shift is related to the velocity of the water current.

The ADCP doppler transducer array sends and receives sound waves in different directions. The frequency shifts of the reflected waves in several directions are used by the ADCP flow meter to estimate the velocity magnitude and direction of the current at various depths. Hence, it can achieve three-dimensional understanding of the current structure.

3.2 What's needed for high-quality measurement of Yantai coastal currents?

Besides, high-quality measurement of the Yantai coastal currents will require several things to be considered. Most importantly, the equipment used should be reliable. The fact that it will be set in the harsh marine environment means that the ADCP current profiler should be manufactured using such materials that can handle the marine environment and climate.

Titanium alloy is a very good material for the casing of ADCP current meter. It is highly resistant to corrosion, and this is an important aspect in the salt-water environment of the coast area. It withstands rusting effects from salt water and other marine organisms, hence giving long life operational performance for the equipment. The other characteristics of the titanium alloy are its strength, yet with low weight. The strength ensures it can support the physical forces exerted on it in the water environment, while at the same time, its lightweight provides for easy handling and installation.

In addition to material reliability, other features like compactness, lightness of weight, small consumption, and inexpensive price are attractive. A small and lightweight ADCP is more easily portable and deployable, and is able to make measurements in diverse locations. Low power consumption allows operation for longer time with less need to change the batteries or use a large supply of power. The cost-effectiveness allows large-scale deployment that would enable wide coverage of the coastal area.

3.3 How to Choose the right equipment for current measurement?

Choosing the right equipment to measure currents at Yantai coast requires consideration of several factors. First of all, the intended use of the equipment has to be considered.

The ADCP would be the perfect instrument type when there is a need for measurements from a vessel in motion. It can give on-site data of the current as the vessel moves alongside the coast, serving for continuous monitoring of the current conditions.

The bottom-mounted ADCP will be applied if the measurement shall be performed at a fixed location on the seabed. It can easily be installed at a specific point and may provide a long-time stable measurement of the current at this point.

With an ADCP mounted on the buoy, open water or any other installation site without the possibility of a fixed platform is allowed. It measures current over a larger area and can wirelessly transmit the data.

As far as choosing the frequency, the greater the water depth, the lower the frequency. For the waters which go up to 70 meters deep, one normally needs to have a 600 kHz ADCP. Up to 110 meters deep, a 300 kHz ADCP will be more relevant. Where water is deep, up to 1000 meters, one should consider a 75 kHz ADCP.

When it comes to choosing an ADCP brand, well - known international brands such as Teledyne RDI, Nortek, and Sontek are popular options. However, for those seeking a cost - effective yet high - quality alternative, the ChinaSonar PandaADCP is worth considering. Made entirely of titanium alloy, it combines durability and reliability with an excellent price - performance ratio. You can find more information about it at https://china-sonar.com.

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