How to measure Ningde coastal currents?

1. Where is Ningde?

Ningde is a time-honored coastal city of Fujian Province in China and is situated northeast of the province, encompassing a beautiful coastal landscape.

Geographically, it is bounded by the East China Sea. The coastline of the city is very long and indents several bays, coves, and inlets within itself. Ningde has a subtropical maritime climate; winters are not too cold, and summers are pretty warm. This area is heavily endowed with rainfall, which further supports a wide range of vegetation. The natural beauty is complemented with a dramatic and attracting meeting of mountains and forests directly into the sea.

Ningde is entitled to a brilliant local culture. People here have their own traditions and folk customs. The most important pillar in the local economy is no doubt fishery and aquaculture. The waters of Ningde abound in marine life: fish, shellfish, seaweeds.

Considering the vastness of the adjacent water areas, the East China Sea near Ningde is a huge area of water relevant in both shipping and fisheries. Generally, the sea floor topography in this area is highly varied: shallow at the coast and deeper further out. The geographically diverse topography affects the distribution of marine resources and water movements.

2. What is the condition of Ningde's coastal currents?

The various factors affecting the coastal current of Ningde are as follows: The monsoon climate is prevailing in this area. During summer, the Southeastern Monsoon brings warm and moist air that sometimes influences the direction and strength of the coastal currents.

Not to be underestimated is the topography of the sea floor. For instance, ridges, shoals, and troughs on the ocean floor can make the water flow in quite different directions and at various velocities. Where seabeds are shallow, currents may be slower-moving, with more or stronger currents in areas with deeper channels.

The other vital factor involves tides. Due to the East China Sea normal rise and fall of tides, there may be strong tidal currents. Hence, they may be very strong at estuaries and narrow passages. They are very fundamental in the maintenance of nutrients and sediments within the water, which determines the growth and distribution of marine life.

Besides, the exchange between the local currents and the more large-scale ocean currents from Taiwan Strait and elsewhere also has the possibility of impacting the Ningde vicinal coastal currents. In fact, such oceanic currents have the capacity to bring in water masses of different temperatures and salinity into this region, which can consequently affect the local current dynamics further.

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

In this light, proper measurement of the coastal currents in Ningde has paramount importance for marine safety, fishery management, and environmental protection. Traditional observation methods of coastal water flow have included the use of buoys and current meters. These traditional approaches have long been used; however, attendant upon them are various serious limitations in both accuracy and coverage.

Acoustic Doppler Current Profiler (ADCP) represent an advance and a much more convenient way of measuring coastal currents. ADCP determine the velocity of water flow through use of the Doppler principle.

3.1 How do Doppler Principle ADCPs work?

ADCP profiler emit a sound wave into the water. The sound waves scatter from the moving particles in the water, such as suspended sediments and small organisms. The motions of the particles cause changes in frequency of the reflected sound waves. This frequency shift is related to the velocity of the water current.

These sound waves are projected and returned in various directions by the transducer array of the ADCP meter . By analyzing frequency shifts of reflected waves in multiple directions, it calculates both speed and direction for the current at different depths. It enables a three-dimensional understanding of the current structure.

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

Quality measurement of the coast currents in Ningde would depend on several factors. First is the reliability of equipment. ADCP flow meter should be produced from materials that could withstand the rough conditions at sea.

One of the best materials for casings of ADCP doppler is titanium alloy. It is highly resistant to corrosion-a vital factor in seawater along the coast. It resists the corrosion by sea water and marine organisms to ensure long performance of equipment. Besides, the titanium alloy is strong and light. Its strength puts it in a position whereby the physical stresses in an ocean environment are easily accommodated, while its lightweight facilitates ease in handling and installation.

Besides material reliability, other features such as compact size, weight, power, and cost-effectiveness have more considerable benefits. Since a small-size and lightweight ADCP current profiler will be much easier to carry and deploy, making measurements in other areas can be included. The low consumption of power, on the other hand, will provide longer operation with no need for frequent battery replacements or large power supply. Cost-effectiveness allows for the deployment of more measurement equipment and an expanded ability to monitor the coastal area.

3.3 How to Choose the right equipment for current measurement?

For successful measurements of the currents in Ningde's coasts, choosing the appropriate current-measuring equipment will be required. Most importantly, when one considers which type of equipment to use, it all depends on what one desires to achieve with the equipment.

This would mean that for displacements made from a vessel in motion, a sufficient tool would be a ship-mounted ADCP. While the vessel cruises along the coast, the current can in this way be mapped in real time, while current conditions are continuously monitored.

If the measurement is to be done at a fixed location on the seabed, then an ADCP mounted at the bottom should be used. It can be installed right there and provide long-term stable measurements of the current of that location.

Applications in open water or sites where fixed installations may not be possible can also be done using a buoy-mounted ADCP. It can measure the current over a much larger area and can transmit data wirelessly.

In choosing a frequency, different frequencies apply to different water depths. For water to a depth of up to 70 meters, a 600 kHz ADCP would normally be appropriate. In cases between 70 and 110 meters, the better choice would be a 300 kHz ADCP. When considering deeper waters of up to 1000 meters, one should look into a 75 kHz ADCP.

When it comes to choosing an ADCP current meter 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 China Sonar ​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.