How are we going to measure Barranquilla's coastal currents?

1. Where is Barranquilla?

Barranquilla is Colombia's fourth city and is situated on the north coast of Colombia where the Magdalena River discharges. Its optimal location has made it a port city and has led it to act as an intermediary between Colombia's extensive geography-based interior and the Caribbean Sea. The city is bordered to the west by the Magdalena River delta, an area of great biodiversity. The delta, with its extensive wetlands and mangrove swamps, is an essential habitat for numerous species of bird, fish, and other animals.

The Caribbean Sea, which borders Barranquilla, has warm, clear water. It is a natural playground for numerous water sports and activities, from sailing and fishing to sunbathing on the beaches. The city itself is an Afro - Caribbean wealth culture. It is famous for Carnival, one of the biggest and most spectacular parties of South America, attracting thousands of tourists every year. The economy of Barranquilla is spurred by a mix of shipping, manufacturing, and tourism industries.

2. What is the condition of coastal currents near Barranquilla?

The offshore currents off Barranquilla are governed by a complex interaction between different factors. Caribbean Sea tides, even relatively small in some areas, still affect coastal hydrodynamics. Semi - diurnal and diurnal tidal periods result in very weak water - level variations, thereby generating weak tidal currents.

Region-dominating winds, primarily northeasterly trade winds, are significant. They push surface water to the west and create a strong westward current along the northern coast of Colombia. The Caribbean Current, one of the globe's largest ocean currents in the region, also plays a role in coastal currents off Barranquilla. Moving to the west along the northern coast of South America, it is blended with wind-driven currents and tides.

The presence of the Magdalena River also impacts the coastal currents. The river discharges a great deal of freshwater into the sea, and this forms a plume that has the potential to change the temperature and salinity of coastal water. This could also impact the density and the flow of the water, and this could lead to complex flow structures in the river mouth. Oceanic eddies formed as different masses of water interact complicate coastal current, causing localized alterations in direction and velocity of the currents.

3. Observation of coast of Barranquilla's water flow

Surface Drifting Buoy Method

One of the traditional methods of observation of coastal water flow is using the surface drifting buoy method. Researchers release buoys with tracking instruments into the sea. By tracking the displacement of these buoys over a period of time, they can determine the direction and speed of the surface currents. This method has its limitations. It provides data only for the surface layer of the water column, and the buoys are extremely sensitive to wind interference. The buoys can be displaced by the wind in a direction that is not representative of the true displacement of the bottom currents.

Moored Ship Method

Fixed ship is employed in the moored ship method as a platform to measure the currents. Sensors are lowered from the ship to observe the water current at varying depths. Despite the fact that the method may be employed to obtain precise vertical profiles of the currents, it possesses several shortcomings. The spatial range is limited to around the moored ship, and the existence of the ship will disrupt the natural flow of the water and thus affect the accuracy of the measurements. In addition, long-duration mooring of a ship might be logistically inconvenient and costly.

Acoustic Doppler Current Profiler (ADCP) Method

ADCP flow meter has become an advanced and efficient method of coastal current measurement. ADCPs have the capacity to measure currents in the water within a large vertical range, providing accurate information on the velocity structure of the water column. ADCPs can be deployed on various platforms, including ships, buoys, and the seafloor. Ship-mounted ADCPs can collect data continuously while the ship moves, covering a broad area within a relatively short time. Bottom-mounted ADCPs have the capability of taking long-term, fixed-location measurements, and therefore researchers are able to research long-term trends in the coastal currents.

4. How do ADCPs based on the Doppler principle operate?

ADCPs operate on the Doppler principle. They emit acoustic pulses into the water. The pulses bounce off suspended material such as sediment, plankton, or bubbles in the water. When the water is in motion, the frequency of the returned pulses changes. By measuring this change in frequency, the ADCP current meter can calculate the velocity of the water relative to the instrument.

Most ADCPs have multiple beams of transducers, typically four or more, at different angles. With this multi - beam configuration, the three - dimensional water velocity can be calculated. By analyzing signals from the different beams, the ADCP can build a complete picture of current velocity at different water column depths. The information gathered by the ADCP can be analyzed in real-time or saved for future analysis, giving useful information on the dynamics of the coastal currents.

5. What's required for high-quality measurement of Barranquilla coastal currents?

For accurate measurement of the coastal currents at Barranquilla, the measuring instrument must possess some essential characteristics. It must be made of long-lasting materials, possess small size, be light in weight, require low power, and be compact at low cost. These characteristics facilitate deployment at a high number of instruments and hence achieve total spatial coverage.

Titanium alloy case ADCP is highly recommended. Titanium alloy possesses better corrosion resistance, a requirement for long - term exposure in the harsh marine environment. Corrosive action of the saltwater is resisted, and the internal components of the ADCP are shielded from damage. Titanium alloy is also strong but light, a required characteristic to enable the durability and transportability of the instrument. The characteristics allow for obtaining trustworthy and long - term measurements of the coastal currents off the coast of Barranquilla.

6. How to Select the correct equipment for current measurement?

Selection Based on Usage

The selection of ADCP is based on its purpose. Ship - mounted ADCPs are the best option for ship - borne measurements. They can give real - time data while the ship is moving in the water, scanning a big area in a relatively short period. For long-term observations at one fixed location, bottom-mounted ADCPs are more desirable. They can record continuous data over a very long duration of time, thus enabling the researchers to know about the coastal currents in long-term terms. Floating ADCPs are utilized where it is necessary to determine the course that a water mass travels over enormous regions, acquiring interesting insight into circulation at the larger scale.

Choice According to Depth

The ADCP frequency also varies with water depth. For water depths less than 70m, 600kHz ADCPs can be applied. They can provide high-resolution data in shallow water. For a depth of 110m and less, 300kHz ADCPs are used. For deeper water levels, ranging from 1000m, 75kHz ADCPs are used.

Several brands of ADCP are already out in the market, such as Teledyne RDI, Nortek, and Sontek. For those in need of economical solutions, however, the ADCP supplier China Sonar's PandaADCP is the best option. Made up entirely of titanium alloy, it is very competent at a comparatively low cost. It is a great choice for those who do not have high budget but need good ADCPs for coastal current measurement. There are additional details at their official website: https://china-sonar.com/.

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