How to measure the coastal currents of Weihai?

1. Where is Weihai?

Weihai City is one of the most beautiful coastal cities in Shandong Province, China. It lies on the eastern tip of the Shandong Peninsula bordering the Yellow Sea and the Bohai Sea. Weihai is a city enjoying a comfortable climate, with fresh air and a coastline displaying fantastic scenery.

Weihai has a temperate-monsoon climate; the winter is relatively mild, and the summer is cool. The sea breeze regulates the temperature. The good weather conditions make this place comfortable to live in and to visit. Rainfall in this area is rich, nourishing various vegetations, from pine forests to coastal grasslands.

Weihai has a long and glorious history of the sea. Once, it was an important naval base and a center for fishery and trade. It is closely tied up with the ocean. The local culture is deeply influenced by the sea, and many of the traditional fishing and seafaring practices remain preserved. The architecture of this city also tells much about its maritime heritage, with numerous old fishing villages and harbors.

The Yellow Sea and the Bohai Sea form the boundary waters of Weihai. The topography of the seabed is quite complicated with shallow and deep areas in the coastal and open areas respectively. Tides, winds, and oceanic currents from the larger sea areas characterise these waters.

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

Many factors are involved in coastal currents around Weihai. Mainly, the monsoon climatic features should be taken into consideration. During summer, the southeast monsoon may push the surface waters to change the directions and strengths of coastal currents. The winds push the water to create a useful pattern for such activities as sailing and fishing. During winter, the northwest monsoon flips the directions and speeds of the current.

The relief of the ocean bottom is not unimportant either. Underwater ridges, troughs, and shoals can make water flow in various directions and at different speeds. Shallow areas might receive slower-moving currents, while deeper regions can have stronger and more complex flows. For instance, near the shoals, the water could be slowing down because of the shallower depth, while in the troughs, the current can be more vigorous.

Another important factor involves tides. At regular tide rises and falls in the Yellow Sea and Bohai Sea, strong tidal currents arise. Near estuaries and narrow inlets, they are comparably stronger. They play an important role in sediment transportation and transportation of nutrition and marine organisms. Tidal current also influences the coastal erosion and deposition processes, hence changing the shape of the coastline and the distribution of marine life.

Furthermore, this can be further modified by the interaction of the local coastal currents with larger-scale ocean currents from the Yellow Sea, the Bohai Sea, and other adjacent regions. Indeed, large oceanic currents can introduce water masses of different temperatures and salinity levels, thus influencing local current dynamics. For instance, intrusions of warmer or colder water masses change the temperature of the coastal waters, hence affecting the local marine ecosystem.

3. How to Observe the Coastal Water Flow of Weihai?

The accurate measurement of coastal currents in Weihai will be very important for many applications, including marine safety, fishery management, and coastal protection. Traditionally, observing coastal water flow has been done for a very long period using buoys and current meters. However, these methods have defects in some ways concerning accuracy and coverage.

The measurement of coastal currents using Acoustic Doppler Current Profilers has emerged as one of the more advanced and convenient ways. ADCPs apply the principle of the Doppler to measure the velocity of water flow.

3.1 How do the Doppler Principle ADCPs work?

ADCPs send sound waves out into the water. Those sound waves scatter off the moving particles in the water, such as suspended sediments and small organisms. As the particles move, the frequency of the reflected sound waves changes. This frequency shift in the reflected sound waves is proportional to the velocity of the water current.

The ADCP transducer array sends and receives sound waves in multiple directions. By observing the frequency shift of the reflected waves in multiple directions, the ADCP calculates the speed and direction of the current at multiple depths. This can be used to create a three-dimensional view of the current structure.

3.2 What's required for fine measurement of Weihai coastal currents?

In making high-quality measurement of the Weihai coastal currents, several factors have to be considered. Equipment reliability is of utmost importance. The ADCP must be made of materials that will stand the adverse conditions in the sea.

One of the most ideal materials for ADCPs casing is the titanium alloy. This is highly corrosion-resistant, an important attribute in salty water of the coast. It has the ability to resist the corrosive effects of sea water and the life forms within the water, hence it ensures that the equipment functions over a long period of time. Besides, the titanium alloy is very strong and lightweight. The strength allows it to stand the physical stresses in the marine environment, and being lightweight in nature makes handling and installation a lot easier.

In addition to material reliability, small size, low weight, low power consumption, and low cost can also be advantageous. A compact and lightweight ADCP is easier to transport and deploy; measurements can take place from more locations. Low power consumption offers a longer operation without changing batteries frequently or bringing large supplies of power. Cost-effectiveness is essential for large-scale deployment to allow the monitoring in the coastal area to be wider.

3.3 How to Choose the right equipment for current measurement?

There are different kinds of equipment used to measure the currents in the sea. While choosing the right equipment to measure the coastal currents in Weihai, several factors are to be considered. A key factor will be the intended use of the equipment.

The ADCP would be ship-mounted for measurements from a moving vessel. This will provide real-time data on the current while it is moving along the coast for the continuity of the current condition.

If a measurement at a fixed location on the seabed must be provided, it shall be done with a bottom-mounted ADCP. In order to do so, it can be installed at a location where long-term stable current measurements can be carried out in that particular location.

A buoy-mounted ADCP would be adopted for applications in open water or where a fixed installation is not possible, with the capability for current measurement over an extended area and data transmission by radio communication.

Frequency Choice: Regarding the choice of frequency, different frequencies apply to different water depths. The 600 kHz ADCP could normally be sufficient for the water depth up to 70 meters. For water depths ranging between 70 and 110 meters, a 300 kHz ADCP would be more applicable. For deeper waters, up to 1000 meters, a 75 kHz ADCP should be considered.

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.