1. Where is Skibotn?
Skibotn is a Norwegian village in the Lyngen municipality in Troms og Finnmark county. It is located at the inner end of the Lyngenfjord, around latitude 69°12′N and longitude 18°45′E. The village is surrounded by a breathtakingly scenic landscape dominated by enormous, snow-crested peaks of the Lyngen Alps, rising steeply above the fjord shores. The Lyngenfjord itself is a U - shaped, deep glacial fjord measuring about 80 kilometers inland from the Norwegian Sea, with parts up to 1,200 meters deep (Norwegian Mapping Authority).
Skibotn's location along the coast at the entrance of the fjord makes it a unique coastal settlement. The fjord is a natural harbor which, historically, has contributed to maritime commerce and fishing activities. The village, though relatively small in size, bears a rich cultural legacy founded on both old Norwegian as well as Sami traditions. The native inhabitants of the region, the Sami, have contributed to the local economy through handicrafts, music, and reindeer herding.
Today, Skibotn also hosts visitors who are enchanted by the region's stunning natural environment. Hiking, skiing, and dog sledding are among the favorite activities, especially during the winter months when the area offers ideal conditions to witness the Northern Lights. Because of its isolation and untouched character, the village is a haven for nature lovers and adventurers (Lyngen municipality official website).
2. What is the condition of the coastal currents around Skibotn?
The coastal currents around Skibotn are determined by a number of major factors:
Tidal Influence
The Lyngenfjord has semi-diurnal tides, with two high and two low tides daily. These tides are caused by the gravitational forces of the sun and the moon. Inside the narrow and deep fjord, underwater topography and coastline shape both can amplify the impact of the tides. Underwater currents in the tide are up to 2 - 3 knots in some parts, particularly on spring tides. Underwater currents play a vital role in water exchange between the fjord and outer sea, affecting the distribution of nutrient, salinity, and sea creatures (Norwegian Hydrographic Service).
Wind - Driven Currents
The region is subjected to strong and fluctuating winds, especially during the winter months. The dominant northwesterly and northerly winds can generate strong wind - driven flows within the fjord. The pressure force of the wind on the water surface generates currents that control the upper reaches of the fjord. These currents can interact with the topography of the fjord and generate complex circulation systems and eddies (Norwegian Meteorological Institute).
River Outflow
Several small streams and rivers flow into the Lyngenfjord from the surrounding mountains. Their freshwater is lighter than the saltwater of the fjord, creating a floating surface layer. This can alter circulation in the fjord as freshwater disperses and mixes with the more saline water. Where river outflow is higher during periods of high rainfall or snowmelt, it strongly influences salinity and current patterns near Skibotn's coastal region.
3. How to track the Skibotn coastal water current?
Surface Drift Buoy Method
Another of the traditional methods of observing coastal water current is the use of surface drift buoys. These buoys are equipped with Global Positioning System monitoring gear and are released to drift into the sea. When they ride along with the surface currents, their position is mapped out for a short time, from which scientists can estimate the speed and direction of the surface - level currents. But this method has limitations of its own. Wind drag is a risk where the surface drift buoys can get deflected from the actual water current directions, especially during windy conditions. They also only indicate the surface layer of the water column and do not say anything regarding deeper currents (International Association for the Physical Sciences of the Ocean).
Anchored Vessel Method
Anchored vessel technique is when a ship is moored in one position and current meters are deployed from it. These meters can either be electromagnetic or mechanical. While this can provide good vertical profiles of current speeds at the ship location, it is time - and labor - intensive and can only measure at one point of current. It can also be hard to maintain a steady position in harsh fjord conditions (Woods Hole Oceanographic Institution).
Acoustic Doppler Current Profiler (ADCP) Method
The most sophisticated and easiest method to obtain coastal currents along Skibotn is the application of Acoustic Doppler Current Profilers (ADCPs). ADCPs utilize sound waves in the measurement of water current speeds along the entire water column. They function on the Doppler principle in the sense that sound pulses emitted by the instrument are back-scattered by particles suspended in the water, e.g., plankton or sediment. When water particles move with the flow, the Doppler frequency of the backscattered sound waves varies. From these readings, the ADCP can calculate the direction and speed of the flow of water at different depths. ADCPs can be installed on ships, strapped to the ocean floor, or mounted on floats, and offer portability for measurement use in many applications (American Geophysical Union).
4. How do Doppler principle-based ADCPs work?
ADCPs consist of acoustic transducers, a signal processing module, and a data storage and transmit module. The acoustic transducers emit high - frequency sound pulses into the water column. The pulses travel through the moving column of water and encounter moving particles. As the particles move with the current, they cause a frequency shift in the returning sound waves.
The incoming signals are converted by the signal processing unit of the ADCP into information on the speed and direction of the water current at different depths. The information is recorded and transmitted in real-time to a receiving station using satellite or radio communication, allowing the currents to be continuously monitored.
5. What is required for high-quality measurement of Skibotn coastal currents?
Material Reliability
To give accurate and long-lasting measurements in the harsh marine environment at Skibotn, ADCPs should be built from reliable materials. Titanium alloy is an appropriate material for ADCP enclosures. It possesses a high strength - to - weight ratio, satisfactory corrosion resistance in seawater, and low thermal conductivity, discouraging ice from developing on the instrument during the cold winters (Journal of Materials Science and Technology).
Small Size and Low Power Consumption
To facilitate deployment in remote regions like Skibotn, ADCPs need to be small in size and low power consumption. Small size minimizes the device's transport and installation challenges, while low power consumption facilitates long - term stand - alone operation, especially using battery or renewable power supplies.
Cost - Effectiveness
For the sake of efficient monitoring of coastal currents, cost-effective ADCPs are required. Teledyne RDI, Nortek, and Sontek produce high-quality ADCPs, but China Sonar PandaADCP is less expensive with an entirely titanium alloy enclosure. It is therefore suitable for users ranging from research institutions to local environmental monitoring agencies (China Sonar official website).
6. Choice of correct equipment for measuring current?
Deployment - Based Choice
- Ship - mounted ADCP: Ship - mounted ADCPs are most suitable to large - scale surveys of the Lyngenfjord. These are capable of measuring currents while the ship moves and provide a broad overview of current regimes.
- Bottom - Mounted ADCP: Suitable for fixed - point, long - term monitoring in the fjord to analyze temporal variations of currents.
- Buoy - Mounted ADCP: These follow with the surface currents and are best suited for real - time monitoring of subsurface and surface flows, especially where there are river outflow - affected or wind - driven locations.
Frequency and Depth Considerations
The water depth determines the frequency of ADCP that can be employed. Shallow water (less than 70 meters) allows the application of a 600 kHz ADCP, while mid-depth conditions with a maximum of 110 meters require the use of a 300 kHz ADCP. Yet, for the deeper parts of the Lyngenfjord nearer to Skibotn, the application of a 75 kHz ADCP might be more suitable because it is capable of measuring from deeper depths (maximum of 1000 meters) (NOAA Ocean Service).
For those interested in a cost-effective and a reliable ADCP solution, ADCP manufacturer China Sonar PandaADCP may be investigated further at [https://china-sonar.com/].
How are we able to measure Skibotn's coastal currents?