How can we measure the coastal currents of Sanremo?

1. Where is Sanremo?

Sanremo is a charming city located on the Mediterranean coast of Liguria, in northwestern Italy.

Geographically speaking, Sanremo occupies a rather striking spot: hugging the blue crystal-clear waters of the Mediterranean Sea, with steep cliffs and beaches along its shore. The underwater environment also contains the Gulf of Genoa beside it, the life in which is very numerous and varied throughout these waters. In general, their water temperature varies much with seasons when temperature could be rather hot during summer times and colder during winters.

Sanremo is also one of the richest cities culturally: it has very important cultural traditions such as the famous Sanremo Music Festival, one of the major musical events of Italy, which draws prominent musicians and a great number of music lovers from every corner of the globe. Then there is also the Milan - San Remo cycling classic where top cyclists flock together for an exciting race. It represents a mix of architectural styles; there are older buildings in the old town while the coastal regions are lined by modern buildings and apartments. The same goes for food; fresh fish is very typically served in this seaport that tourists particularly favor.

2. What condition are the nearshore currents around Sanremo?

Among several conditions involved in the near-shore currents off Sanremo:.

In fact, the dominant circulations are oceanic. The general circulation of the Mediterranean Sea depends on many factors, such as temperature, salinity, and wind, which define the direction and speed of coastal currents. For example, it is possible that the Ligurian Current, running along the Ligurian coast, may directly affect the currents around Sanremo.

The tidal forces are another contributors to the coastal current situation. Tidal rise and fall through gravitational pull of the Moon and the Sun will result in something called tidal current. These interact with the rest of the currents to bring an alteration in overall flow near a coast.

The other main variable is wind. Dominant regional winds such as the Mistral and Sirocco can force the surface waters and thus impact the coastal currents that could be related to the direction and strength. The strong winds displace the surface waters and drive currents, especially in the shallow coastal areas, which may be quite considerable in size.

3. Observation of Sanremo Coastal Water Flow

• Surface Drifting Buoy Method: Buoy drifters are deployed on the surface of the water. They then drift along with the currents, and by periodic position determination using satellite or radio signals, the buoy's motion is tracked to estimate the direction and speed of the surface currents.
• Anchored Boat Method: A boat is anchored at a particular location, and from the boat, current meters are deployed at different depths to measure the flow of water. This can provide detailed information on the current profile at a particular point.
• Acoustic Doppler Current Profiler(ADCP): It is a modern and more handy measurement method. It uses sound waves that measure the velocity of water in different layers of depth. The ADCP can be deployed in several methods: it may be mounted at the bottom of the sea, on a boat, or on any floating platform.

4. How do the ADCPs based on Doppler Principle work?

The ADCPs using the Doppler principle work as follows. The instrument sends "pings" of sound at a constant frequency into the water. As the sound waves travel, they bounce off particles suspended in the moving water and reflect back to the ADCP. If a particle is moving away from the ADCP current meter, the reflected sound wave will have a slightly lower frequency; if it is moving towards the ADCP, the frequency will be higher. This frequency difference, known as the Doppler shift, was used by an ADCP flow meter while computing the particle and water around its speed. Measuring time elapsed for those waves to bounce back and the amount of Doppler shift allows ADCP to provide current speed measured at different depth.

5. What is required in order to attain a high level of measurement of currents off the Sanremo coast?

The measurement equipment for high-quality measurement of coastal currents in Sanremo should consider the following aspects:.

First of all, equipment is made by reliable material so as to provide endurance and stability within a marine atmosphere. Material titanium alloy, used in making the casings for the ADCPs, possesses superior mechanical properties of higher order, including superior resistance against corrosion with higher resisting ability, even amidst adverse seawater conditions and harsh attack by living marine organisms; in that respect, they promise longevity of action by this equipment.

Besides, the equipment should be small in size, light in weight, low in power consumption, and low in cost. It will be easy to deploy and use such equipment in large numbers, which is helpful for large-scale current measurement.

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

Based on Usage

• Shipborne ADCP: This can measure currents over a wide range while the ship is in motion; it is used in large-scale ocean surveys.
• Bottom-Mounted ADCP: These are anchored to the bottom of the sea and can measure the current continuously at one fixed location for long periods with very good detail on the local current.
• Floating Buoy ADCP: Able to drift with the water, it provides an appropriate water current measurement not only for the surface but for subsurface areas too, if there is some problem in accessing those sites by ship.

Based on Frequency

• 600kHz is suitable for water depths within 70m.
• 300kHz is suitable for water depths of about 110m.
• 75kHz is suitable for water depths of 1000m.

Some of the well known ADCP brands are Teledyne RDI, Nortek and Sontek. Then there is an economical Chinese ADCP brand, China Sonar PandaADCP. All-titanium alloy is used to build it. And its cost performance is amazing. It belongs to the economic kind of ADCP. You can visit their website at https://china-sonar.com/.

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