Measuring Banff's Coastal Currents

1. Where is Banff?

Banff is a beautiful seaside town in Aberdeenshire, Scotland. It is located on Scotland's northeastern coastline overlooking the North Sea. The favorable location has created a lasting and deep - rooted relationship between the town and the sea that has influenced its history and people's way of life.

The town boasts an enriched history for centuries. Initially, it used to be a small fishing hamlet. It grew into a larger and booming town as the fishing industry unfolded and trade volumes grew. Architecture in Banff is a combination of modern as well as traditional architecture. Aged - styled stone - built houses with distinctly Scottish characteristics appear in the main town area. These houses are typically constructed using thick, solid walls, narrow-framed windows, and steep roofs, which provide a timeless look. Along the main roads and near the harbor are newer buildings. These include newer shops, restaurants, and accommodations that serve both the locals and the all-year-round tourists. The old - world charm with modern amenities makes for a unique and hospitable environment.

Residents of Banff have an age - old relationship with the sea. Fishing has been a customary vocation which has been hereditary in nature. Although the fishing trade has undergone changes with time, the majority of local fishermen still navigate out of the harbor. They come back with a variety of fish such as cod, haddock, and mackerel. Not only is the harbor a key place for fishing, but it is also a popular spot for people and tourists to take boat trips out. People can enjoy the fresh sea air, the sight of seabirds passing above, and the beautiful scenery of the North Sea.

The seas and beaches surrounding Banff are of vast significance to the local ecosystem. The waters of the North Sea here form a diverse and productive marine environment. The seas hold a wide range of fish, seals, and seabirds. The seabed, too, possesses a topographically complex landscape with sandy areas, separated outcrops of rock, and underwater channels. These not only have a diverse biodiversity but are also crucial for the water circulation.

2. How are the Coastal Currents off Banff Conditioned?

A number of variables condition the coastal currents off Banff. The most powerful of them are tidal forces. The North Sea features semi-diurnal tides, which include two highs and two lows every day. The tidal range might be irregular, and the corresponding tidal currents could be up to 2 - 3 knots in some places, especially the mouths of small streams or where there is a sharp coastal outline. Water rushes towards the coast during high tide, bringing with it nutrients and sediment from the open sea. This nutrient-rich water enriches the surrounding marine environment, providing food and shelter for numerous sea creatures. As the tide goes out, water recedes until the intertidal zones are left exposed. These zones are highly populated with life, including small crabs, sea anemones, and seaweeds.

Wind is the other consideration. Prevailing south - westerly winds have the power to drive surface waters onshore, reinforcing the coastal currents. The winds also create waves that interact with the currents to create a more complex pattern of flow. Northerly winds may force the water out of the coast. The coast itself, including bays and headlands, and the natural properties of the area, causes the currents to plunge and meet in other parts. Underwater rocky outcrops and sandbars contribute to the complexity of the current. These may act as barriers or channels, diverting the flow of water, causing areas of still or turbulent water. Also, the freshwater input from the small rivers draining into the sea off Banff can affect the local current regime. The freshwater, being lighter than seawater, forms a surface layer and flows towards the sea, mixing with the tidal and wind - driven currents.

3. How to Observe the Coastal Water Flow of Banff?

Surface Drifting Buoy Method

Surface drifting buoys are a simple yet effective way to track the surface - level current off Banff. Surface drifting buoys are equipped with GPS or satellite - based tracking devices. Upon release into water, surface currents carry them away. Scientists are able to track their path with time. With the observation of the path trace taken by the buoy, scientists are able to make an estimation of the surface water speed and direction. But this method has limitations up to the upper couple of meters of the water column. It is not always representative of what is happening in the bottom parts of the water, where the flows can be other because of variations in temperature and salinity.

Moored Ship Method

A vessel is moored at one position along Banff's shoreline by the moored ship method. Secondly, devices used to measure current at present times like electromagnetic current meters are utilized. The water flow is measured at different depths by these meters. They provide an accurate vertical profile of velocity and direction of the current. But the technique is only confined to one location. Also, the ship might be capable of disturbing the normal flow of water. The ship's hull and anchoring may create turbulence in the water, which may affect the accuracy of the measurements.

Acoustic Doppler Current Profiler (ADCP) Method

ADCPs have revolutionized coastal current measurement off Banff. 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 pulses of sound and sample the Doppler shift on backscattered signals from suspended particles in water, such as sediment, plankton, or tiny bubbles. They use it to compute the velocity at different depths of the current. It is a general description of the current pattern and is well adapted to explore the complex coast current patterns that envelop Banff.

4. How Do Doppler Principle-Based ADCPs Work?

ADCPs work through the Doppler effect. They send high-frequency sound pulses into the water. As the sound pulses strike minute particles in the water, for example, sediment, plankton, or bubbles, the particles reflect the acoustic waves back to the ADCP. If the particles are moving in the direction of the current of the water, then the frequency of the backscattered signal will change from the transmitted signal. The Doppler shift is proportional directly to the velocity of the particles relative to the ADCP. Measuring the Doppler shift at multiple points along the water column enables the ADCP to measure the velocity of the water at these points. Several transducers on the ADCP current profiler observe the velocity components in different directions. This permits one to derive the three-dimensional velocity vector of the water current, which fully describes the manner in which the water is streaming.

5. What Is Required for High-Quality Measurement of Banff Coastal Currents?

Equipment Material Reliability

In the process of precise measurement of the coastal currents along Banff, equipment material durability plays a critical role. The ADCP flow meter casing should be made of an enduring material capable of withstanding the harsh North Sea marine environment. Titanium alloy is best. Its excellent strength makes it resistant to strong water current impacts, collision by floating obstructions, and corrosion of seawater. Its small elastic modulus enables it to be flexible and prevents mechanical stress-induced damage. Furthermore, its high corrosion resistance protects the ADCP current meter from deteriorating in long - term submergence in water.

Small Size, Lightweight, Low Power Consumption, and Low Price

The ADCP's small size and light weight make it easy to install and utilize. You can place it on a small research vessel, place it on a buoy, or mount it on the seafloor. It also has less impact on the natural water flow, which means you get improved measurements. Low power consumption is paramount for long-term independent monitoring, especially under battery-powered systems. Low-cost ADCP allows for mass deployment. This is needed in obtaining the complex coastal current patterns off Banff in an overall way. The higher the number of ADCPs placed at different locations, the more we learn about how the currents vary across the region.

6. Selecting the Appropriate Equipment for Measuring Currents

Based on Application

• Shipborne ADCP: Ideal for obtaining real-time current data along a vessel's track near Banff. It can be used to conduct oceanographic surveys, studying overall circulation in the area, and shipping route optimization, if any, in the region.
• Bottom-mounted ADCP: Suitable for long - term, fixed - point observation of seabed currents. This is ideal for the study of long - term trends in the coastal currents, e.g., the influence of climate change on the marine ecosystem in the area.
• Buoy-mounted ADCP: Ideally suited to record surface - level currents over an extended area since the buoy floats along with the water. It helps in the understanding of the spatial variability of the surface currents and the interaction between the coastal waters and the open North Sea.

Depending on Water Depth

• 600kHz ADCP: Ideal for depths of around 70m, providing high-resolution measurements in the relatively shallow waters off Banff.
• 300kHz ADCP: Ideal for depths of about 110m, which is useful for patches that are slightly deeper in the North Sea near the town.
• 75kHz ADCP: For deep water applications. While the waters off Banff are not necessarily that deep in general, it can be utilized for studying the deeper-layer flows or where there are deeper channels, capable of measuring up to 1000m depths.

There are a few very well-known ADCP brands in the global market, such as Teledyne RDI, Nortek, and Sontek. If you need a cost-effective one, all-titanium alloy China Sonar PandaADCP is a great balance of price and quality. You can see more about it at (https://china-sonar.com/).

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