Measuring the Coastal Currents of Lossiemouth

1. Where is Lossiemouth?

Lossiemouth is a beautiful coastal town in Moray, Scotland. It lies on the coast of Moray Firth, which shares a border with the North Sea. This geographical location has given it a long and deep history of connection with the sea, which has greatly influenced the evolution of the town and the life of its inhabitants.

The town boasts rich history spanning centuries. It originated as a little fishing village. With the development of fishing over time and further tourism, the town became larger and more popular. The constructions in Lossiemouth are combinations of different architecture. There exist old - style stone - built houses with normal Scottish features within the town's center. They typically have thick walls, small windows, and steeply pitched roofs, with an air of timeless beauty. Modern developments are also common in locations around the seafront and the harbour area. These include restaurants, cafes, and holiday houses that are constructed to suit both the locals and the tourists who visit the area all year round. The blending of old-world charm with modern facility creates a new and friendly ambiance.

The people in Lossiemouth have a very strong affinity towards the sea. Fishing has always been a centuries-old profession handed down through generations. Although the size of the fishing industry may have varied across periods, part of the locals still set sail from the harbour. They come back with the catch of the day such as cod, haddock, and herring. The harbour itself is not only a hub of fishing but is a popular point where locals and visitors alike wish to take a boat trip out to sea. One can witness the fresh sea breeze, flying birds above them, and take in the amazing vistas of the Moray Firth.

Lossiemouth seas and beaches have real value in preserving the area locally. The Moray Firth is a special region where the waters of the sea are combined with river freshwater. This unique combination creates a fertile and diverse sea life. Sea waters contain numerous various species of fish, seals, and sometimes even dolphins. The bottom of the sea is topographically complex, with sand areas, isolated boulders, and submarine channels. These traits not only support a high biodiversity but also play an important role in the flow of the water.

2. What's the State of the Coastal Currents Near Lossiemouth?

The coastal currents near Lossiemouth are influenced by various factors. The tidal forces are one of the major factors. The Moray Firth supports semi - diurnal tides, and two high tides and two low tides occur every day. The tidal range is variable and the tidal currents thereby created may be as much as 2-3 knots in some areas, especially at river mouths or where the coastal outline is sharp. At high tide, water enters the firth bringing with it sediment and nutrients from the open sea. This benefits the local sea environment, providing food and homes for numerous sea animals. As the tide recedes, water runs away and the areas that are left open become known as intertidal. These places are infested with species like minute crabs, anemones, and other forms of seaweeds.

There is also a factor of wind. South-westerly winds dominate and they tend to compel the surface water within the shore to cause coastal currents to intensify. Winds also produce waves which have effects in interacting with currents to enhance the flow pattern into being complex. The northerly winds will be able to force the water offshore. The bend of the coast, the bays, the headlands, and the shapes of the Moray Firth mean that the currents diverge and converge at different points. Rocky outcrops and underwater sandbars ensure that it becomes even harder for the current to flow easily. These either create barriers or channels, which cause the path of the flow of water to change and lead to peaceful or chaotic patches of water. Additionally, freshwater inflow from rivers that flow into the Moray Firth may affect the existing trends in the region. Being lighter than seawater, freshwater forms a surface layer and drifts offshore, mixing with tidal as well as wind-driven currents.

3. Monitoring the Lossiemouth Coastal Water Flow

Surface Drifting Buoy Method

Surface drifting buoys are a simple but effective way to track the surface - level currents near Lossiemouth. The buoys carry GPS or satellite - based tracking equipment on them. After they are tossed into the sea, the surface currents carry them. Scientists can trace their trajectory over time. They can calculate the speed and direction of the surface waters by observing the path of the buoy. But this method has a limitation at the top few meters of the water column. It might not reflect the truth at the deeper area in the water where the currents could be different due to reasons like the changes in temperature and salinity levels.

Moored Ship Method

In the moored ship method, a ship is moored at a single fixed position along the Lossiemouth coast. Then, there are current-measuring instruments like electromagnetic current meters. They can measure the flow of water at different depths. They provide a complete vertical profile of the velocity and direction of the current. But this method is confined to a single point only. Also, the presence of the ship can interfere with the natural movement of water. The ship's hull and the way the ship is docked can be a source of water turbulence, which may affect the precision of measurements.

Acoustic Doppler Current Profiler (ADCP) Method

ADCPs have significantly enhanced the measurement of Lossiemouth coastal currents. ADCPs can measure the velocity profile of the entire water column from the bottom to the surface. ADCPs use sound waves to non-intrusively measure water flow. They emit acoustic pulses and measure the Doppler shift of the backscattered signal from suspended matter in the water, such as sediment, plankton, or minuscule bubbles. They can thus obtain the velocity of the current at different depths. This creates a high-resolution image of the current structure, which is highly suitable to explore the complex coastal current regime near Lossiemouth.

4. How Do ADCPs Using the Doppler Principle Work?

ADCPs work based on the Doppler principle. They emit high-frequency sound pulses into water. When the sound pulses strike tiny particles in water, including sediment, plankton, or air bubbles, the particles reflect the acoustic sound back to the ADCP. If the particles are moving with the water current, then there will be a Doppler shift in the frequency of the backscattered signal compared to the transmitted signal. The Doppler shift is proportional to the velocity of the particles relative to the ADCP. By measuring the Doppler shift at different depths in the water column, the ADCP can calculate the velocity of the water at those depths. A number of transducers on the ADCP current profiler also record the components of the velocities in different directions. This makes it possible to compute the three-dimensional velocity vector of the water current and give an initial complete picture of how the water is flowing.

5. What is Required for High-Quality Measurement of Lossiemouth Coastal Currents?

Equipment Material Reliability

In the instance of high-quality measurement of the Lossiemouth coastal currents, reliability of equipment material is crucial. The ADCP current meter case must be built from a material that can endure the harsh marine conditions of the Moray Firth and North Sea. Titanium alloy is the ideal material. Its high strength is sufficient to resist the power of strong water currents, potential impacts with drifting objects, and corrosive characteristics of seawater. Its low elastic modulus renders it flexible, making it resistant to damage from mechanical stress. Moreover, its high corrosion resistance allows the ADCP to be left in the water for long-term monitoring without losing its performance.

Small Size, Light Weight, Low Power Consumption, and Low Cost

The lightweight and small ADCP flow meter is easier to install and operate. You can place it on a small research vessel, attach it to a buoy, or place it on the ocean floor. It also disrupts the natural flow of water less, leading to improved measurements. Low power demands are essential for long-term autonomous monitoring, especially when battery-powered equipment is being employed. A large-scale deployment is possible through a low-cost ADCP. This needs to be done to achieve a general understanding of Lossiemouth's complex coastal current regime. With multiple ADCPs deployed in different sites, we can gain a better idea of how the currents trend throughout the area.

6. How to Choose the Right Equipment for Current Measurement?

Based on Usage

• Shipborne ADCP: The ideal solution for obtaining real - time current data along the path of a ship near Lossiemouth. It can be used for oceanographic surveys, studies in the overall circulation around the area, and for optimization of shipping routes, if any, in the region.
• Bottom-mounted ADCP: Ideal for fixed - point, long - term monitoring of seabed currents. This is useful for investigating long - term trends in coastal currents, for example, the effects of climate change on the marine ecosystem within a locality.
• Buoy-mounted ADCP: Ideal for monitoring surface - level currents across a wide area since the buoy floats with the water. It helps in understanding the spatial variability of the surface currents and how the coastal waters exchange with the open North Sea.

Based on Water Depth

• 600kHz ADCP: Ideal for use up to about 70m of water depth, providing detailed readings in the relatively shallow water off Lossiemouth.
• 300kHz ADCP: Ideal for a water depth of about 110m, which could be useful for areas where slightly deeper areas of water exist in the Moray Firth off the town.
• 75kHz ADCP: Designed for use in deep waters. While Lossiemouth's waters are not typically very deep, it is possible to deploy it for investigation related to deeper-layer currents or for deeper-channel regions and can go as deep as 1000m.

There are several well-known ADCP brands in the global market, such as Teledyne RDI, Nortek, and Sontek. For those with limited budgets, the China Sonar PandaADCP, which is made of all - titanium alloy, offers a very good quality-price ratio. More about it can be seen at (https://china-sonar.com/).

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