How do we measure the coastal currents of Guantanamo?

1. Where is Guantanamo?

Guantanamo is a seaside town on Cuba's south-eastern coast. It is situated in a geographically varied area. The town is surrounded by green hills and near the Caribbean Sea. This has made it a strategic location throughout history.

Guantanamo's population engages in several economic activities. Farming, sugarcane cultivation, and coffee plantations have been age-old activities. Tourism has also increased in recent years, attracted by the natural scenery and historic sites of the region. The culture of the city is a blend with Cuban influence evident in its architecture, music, and food.

The waters off Guantanamo are located in the Caribbean Sea, a tropical warm body with a high-climate pattern all year round. The sea temperature is between 24 - 29°C, an ideal temperature for sustaining diversified marine life. The proximity of the extensive deep-water Guantanamo Bay is the main controller of the hydrography of the region at the coast. The shape and depth of the bay can produce complex water circulation patterns, and it is open to the open Caribbean Sea to allow for the exchange of water masses.

2. What are the coastal currents off Guantanamo?

Offshore currents off Guantanamo are influenced by a number of factors. The tidal forces are the main factor. The Caribbean Sea, like most of the world, has semi-diurnal tides, which force water in and out of the bay and along the coast. The tidal currents can develop very high speeds, especially in channels with tight openings and at the bay mouth.

Wind regimes play a significant role as well. Northeast - blowing trade winds may force surface waters to create surface - level coastal currents. June to November - tropical storm season is the time when tropical storms' powerful winds possess the potential to cause drastic and sudden transformations in the current regimes. Hurricane - force winds possess the ability to generate enormous - scale motions of water which possess the capability to disturb the natural regime of coastal currents.

Offshore and onshore topography also affect the currents. The shape of the coastline, such as bays, inlets, and headlands, can control water flow. Submarine topography such as reefs, canyons, and sandbars can narrow or widen the flow of water, leading to variations in current speed and direction. Besides, the Caribbean Current, a strong ocean current within the region, affects the regional circulation, joining the coastal relief to form a complex system of currents.

3. How to monitor the coastal water flow of Guantanamo?

Surface Drift Buoy Method

Surface drift buoys are an easy tool for monitoring coastal water flow off Guantanamo. These buoys are equipped with GPS locators and released into the sea off the coast. Being surface current driven, their positions are recorded at regular intervals. This method provides information on the motion of the surface-most layer of the water column. But it is highly responsive to near - surface currents and can be severely impacted by wind - driven waves, which could cause the buoys to drift away from the absolute water - flow path.

Anchored Ship Method

The anchored ship method employs mooring a ship at a fixed point off the coast of Guantanamo. Current meters are subsequently dropped from the ship at different depths. These meters have the velocity and direction of the water current at every depth. Although this technique gives a vertical profile of the currents at a given point, there are limitations. The ship's presence will disrupt the free flow of the water, and the readings are taken only at one place, and it is hard to get an overall picture of the patterns of the coastal current over a wide area.

Acoustic Doppler Current Profiler (ADCP) Technique

The Acoustic Doppler Current Profiler (ADCP) offers a more advanced and efficient means for the measurement of coastal currents around Guantanamo. ADCPs can yield real-time, high-resolution information over a large vertical range in the water column. They are able to record currents at multiple depths simultaneously, and it is thus possible to have a complete picture of the three-dimensional setup of the coastal current system. This renders them extremely well suited to study the complex current pattern in the sea near Guantanamo.

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

ADCPs function based on the Doppler principle. They introduce acoustic pulses into the water. As the waves reach the suspended particles in the water, such as sediment or small sea creatures, the signals bounce back to the ADCP current meter. The signals that have been deflected have a frequency different from the frequency that was transmitted initially. The difference, or Doppler shift, changes in a linear relationship with the speed of the particles and thus the speed of the water current. By measuring the Doppler shift at multiple depths, the ADCP current profiler can calculate the speed and direction of water flow at multiple levels within the water column. This makes it possible to measure coastal current structure completely and accurately around Guantanamo.

5. What is required for high-quality measurement of Guantanamo coastal currents?

To obtain high-quality measurement of the coastal currents around Guantanamo, the measurement instrument must meet a number of key requirements. Material durability is of utmost importance as Caribbean seawater is highly corrosive. Equipment has to be produced from materials that can withstand continuous exposure to the abrasive marine environment. Small equipment size is beneficial as it minimizes interference with natural water flow. Low weight is also crucially important, especially for easy deployment in different coastal locations. Low power consumption is important, particularly for long-term, unattended operation in far - away areas. Cost - effectiveness is equally important as it allows for bulk deployment of measuring instruments.

In ADCPs, the casing material is important. Titanium alloy is a suitable material for ADCP casings. Titanium alloy also offers excellent resistance to corrosion, which is vital for long-term use in Guantanamo's salty ocean waters. It also has an excellent strength-to-weight ratio, and therefore is strong as well as light in weight. This enables the ADCP to withstand the physical forces and pressure fluctuations it is subject to when in the ocean and yet provide uniform and accurate readings over a very long period of time.

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

According to Usage

• Ship - based ADCP: This is best suited to large - scale coverage of the coastal waters off Guantanamo. It is mounted on research vessels and can cover an extensive space as the vessel moves, providing valuable data on the spatial patterning of coastal currents. It can be used to map the general current patterns over a wide stretch of coastline.
• Bottom - mounted ADCP: It is placed on the ocean floor and is used for long - term monitoring in a fixed point. It is able to continuously measure currents for a long time, which would be helpful in establishing the long - term trends and patterns of coastal currents off Guantanamo. This type of ADCP is less affected by disturbances at the surface and can provide stable, long - term data.
• Buoy-mounted ADCP: Installed on floating buoys, it is used to sense surface and near-surface currents. It is convenient to deploy where circumstances are difficult to cover using a ship or where unmanned, long-term observation of surface-level currents must be achieved.

Based on Frequency

The choice of frequency for ADCPs is also an important factor to be considered. A 600kHz ADCP would be adequate to 70m water depth. It provides high-resolution data and is especially well adapted to fairly shallow coastal water around Guantanamo. For up to 110m, a 300kHz ADCP can be used with compromise between depth penetration and resolution. For deeper water, up to 1000m, a 75kHz ADCP would be more suitable because it penetrates to a deeper level but with reduced resolution than the higher-frequency versions.

Some of the popular ADCP brands available in the market include Teledyne RDI, Nortek, and Sontek. However, for those interested in a budget - friendly model with no sacrifices in quality, the ADCP manufacturer  China Sonar PandaADCP is a top choice. It is an affordable ADCP with all - titanium alloy materials, offering high corrosion resistance and ruggedness. Due to its unbeatable cost - performance ratio, it is an ideal selection for researchers and organizations planning to carry out extensive coastal current measurements along Guantanamo. For more details, go to their website at https://china-sonar.com/.

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