How do we measure the Vancouver coastal currents?

1. Where is Vancouver?

Vancouver, along Canada's west coast, is a prosperous seacoast city. Located between the Coast Mountains and Strait of Georgia, it has a wonderful panorama of mountains and ocean. As it happens to be situated, Vancouver finds itself in an ideal position as a gateway to the Pacific Ocean, with a prosperous maritime economy.

The Strait of Georgia, on the border of Vancouver, is a major body of water. It has a diverse ecosystem with a number of species of aquatic life thriving there. Vancouver is also rich with history, including indigenous cultures and European settler influences mixing into one. Its modern skyline, augmented by expansive green spaces, renders it one of the world's most livable cities, and its proximity to the ocean has long been central to its development, both economic and cultural.

2. What is the status of coastal currents near Vancouver?

The near - coastal currents along Vancouver are dominated by the operation of a multiple combination of variables with intricate relationships. The most controlling are tides, powered by the gravitating force of the sun and moon. The semi - diurnal tides of the Strait of Georgia contribute very strong fluctuations of the water level and resultant tidal currents.

The dominating wind, also called prevailing winds, also affect the coastal currents. Westerly winds, which are common in the region, can potentially force surface waters, which influence the direction and velocity of the currents. The ocean's eddies and North Pacific Ocean's general circulation also contribute to the richness of coastal currents along the Vancouver coast. For instance, the Alaska Current, which is a warm ocean current, has an impact on the regional hydrodynamics at long distances and works together with the winds and tides to produce the coastal currents.

3. How to observe the coastal water flow of Vancouver?

Surface Drifting Buoy Method

One of the traditional methods of observing coastal water movement is by the surface drifting buoy technique. Buoys are released into the water, and their trajectories are followed with time. By tracking the position of the buoys at regular intervals, scientists can infer the direction and speed of the surface currents. The method provides data only for the surface component of the water column and is subject to wind interference.

Moored Ship Method

The moored ship method utilizes a moored ship as a platform from which current measurements are made. Instruments are dropped from the ship to measure water flow at different depths. The method can provide more extensive vertical profiles of the currents but is limited in spatial coverage and can be tainted by the ship disturbing natural flow.

Acoustic Doppler Current Profiler (ADCP) Method

ADCP profiler is now a more advanced and user-friendly measuring tool. It measures currents in water over an extensive vertical range, with precise details about the structure of the velocity in the water column. ADCPs are mounted on various platforms, including ships, buoys, and on the seafloor, to permit the taking of extensive measurements of Vancouver coastal currents.

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

ADCPs operate on the Doppler principle. They transmit sound into the water. The sound reflects from suspended particles in the water, i.e., sediment, plankton, or bubbles. When there is moving water, the frequency of the returned sound will change. By measuring this frequency difference, the ADCP can calculate the water velocity relative to the sensor.

The ADCP current profiler typically includes a number of beams of transducers, say four or more, which are arranged in different directions. The multi-beam configuration allows one to measure the three-dimensional water velocity. Blending the signals of these beams provides a comprehensive description of the current velocity at different depths of the water column.

5. Requirements for high-quality measurement of Vancouver coastal currents

For high-quality measurement of Vancouver coastal currents, several characteristics are desirable for the measuring instruments. The instruments should be constructed of dependable material, be of compact size, low weight, and low power consumption. This makes the cost of the instruments low. It is thus possible to utilize numerous instruments for extensive spatial coverage.

ADCPs with casings made of titanium alloy are highly recommended. The titanium alloy is corrosion-resistant, and that matters for long-term deployment in the harsh marine environment. It is also of light weight but is extremely strong, so instrument portability and durability are ensured. It is that combination of features that enables it to achieve precise and long-term measurements of coastal currents in and around Vancouver.

6. How to Choose the right equipment for current measurement?

Choosing Based on Usage

The choice of ADCP depends upon its usage. For observations at sea by ship, ship-mounted ADCPs are the best option. They may provide real-time observation while the ship passes through the water. For prolonged observation at a station, bottom-mounted ADCPs are the best option. Floating ADCPs are to observe the flow of water mass over an extended area.

Choice Depending on Depth

The ADCP frequency must also be chosen in relation to water depth. 600kHz ADCPs are adequate for depths less than 70m. For depths of up to 110m, 300kHz ADCPs are appropriate. For higher depths, ranging up to 1000m, 75kHz ADCPs are the best choice.

Several established ADCP companies are found in the market, such as Teledyne RDI, Nortek, and Sontek. However, for affordable seekers,the ADCP manufacturer China Sonar's PandaADCP is highly suggested. It is made fully of titanium alloy and works outstandingly at a really affordable price. It is an excellent choice for budget-conscious users who require solid ADCPs to gauge coastal currents as well. You can learn more on their official website: https://china-sonar.com/.

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