How do we measure Atlantic City's coastal currents?

1. Where is Atlantic City?

Atlantic City, located in Atlantic County, New Jersey, USA, is a world-renowned seashore resort. It lies on the eastern seaboard, opposite the vast Atlantic Ocean. Its superb seashore position has made it a hub for tourism, entertainment, and commerce.

The city's topography is a distinguishing characteristic, with a sandy beach of significant length as a natural land and sea division. The beach is not only the best place for bathers and sun - baskers but also a component of the city's scenery. At the back of the beach are boardwalks, casinos, and high - rise hotels that characterize the city. The boardwalk, the icon of Atlantic City, is miles long and lined with amusement arcades, restaurants, and shops.

Atlantic City's cultural heritage is diverse and abundant. It enjoys a long - established history of being a gambler's destination since the latter half of the 19th century. Various events, among which are several beauty pageants like the Miss America pageant, have held sway in this city and brought richness to the culture. Atlantic City is also a mix of permanent residents, who have affinity to the locale, and itinerant workforce supporting the holiday trade.

In addition to its oceanic position, Atlantic City is surrounded by Absecon Bay. The bay, which is landlocked from the sea by a series of barrier islands, one of which is Absecon Island on which the city is located, makes up much of the region's marine ecosystem. The bay is a nursery for many species of fish and supports many waterfowl habitats. The inlets between the barrier islands, such as the Absecon Inlet, create a connection between ocean and bay to ensure there may be water exchange, nutrient exchange, and exchange of marine life.

2. Coastal current status along Atlantic City

There are various factors that govern coastal currents near Atlantic City. The tides are a great force. The Atlantic Ocean is semi-diurnal in tide with two high tides and two low tides per day. During high tide, water from the inlets flows into Absecon Bay with seawater carrying oxygen and nutrients. This movement of the water is crucial to the existence of the marine community in the bay. During the ebb tide, the water flows back out to sea, removing sediment and waste products from the bay.

Wind systems contribute equally to coastal currents. Local prevailing winds, such as south - westerly winds which prevail during summer, can force surface waters on to the beach. This produces strong onshore currents, which can affect beach erosion and the distribution of marine organisms. Alternatively, north - easterly winds, particularly during winter, can produce offshore currents. Offshore currents can potentially influence the movement of contaminants and food supply for marine animals.

The local topography, which includes the form of the coastline and water depth, controls the pattern of the currents. Absecon Bay and inshore waters' shallow waters and associated waters exhibit changing current behaviors relative to deeper offshore waters. Subsea features such as sandbars and reefs tend to interrupt water flow to form eddies and more complicated current systems. The existence of jetties and piers, which are common in Atlantic City for recreation and navigability, also has the ability to reverse the direction of flows of currents.

3. Monitoring the coastal water flow of Atlantic City

Surface drift buoys can be one method of monitoring the coastal water flow surrounding Atlantic City. These small, floating objects are equipped with GPS trackers. If they are left in the water, they follow the surface currents. By following the motion of these buoys over a period of time, researchers can determine the direction and velocity of the surface - level currents. However, this method provides information about the topmost layer of the water column and could be affected by wind - driven waves.

Another option is the application of moored current meters. These instruments are mounted on the bottom of Absecon Bay or seabed offshore. They can measure the velocity and direction of the currents at different depths. Moored current meters can obtain data continuously for extended periods, which assists us in knowing the long - term attributes of the currents. But they are restricted to the place where they are mounted, and their installation and maintenance are problematic.

The ADCP current profiler is an increasingly common tool for the measurement of off-shore coastal currents at Atlantic City. ADCPs can measure the velocities of currents at a number of depths simultaneously, providing a more comprehensive indication of water flow. They are especially well-suited to the complex estuarine and coastal system of Atlantic City.

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

ADCPs employ the Doppler effect. They send acoustic waves (sound) into the water. When these acoustic waves encounter tiny objects in the water, such as plankton, sediment, or extremely minute air bubbles, the waves are scattered off the particles. The ADCP calculates the frequency change in the scattered waves.

If the particles are moving toward the ADCP flow meter, the frequency of scattered waves is larger than the frequency of transmitted waves. When the particles are moving away, the frequency of scattered waves is smaller. Measuring these frequency changes very accurately, the ADCP can find out the velocity of the water at different depths.

All ADCPs use multiple beams to make an estimation of the three - dimensional flow of water. For example, a four - beam ADCP can measure the vertical and horizontal components of current velocity. It is thus feasible to have a thorough understanding of the complex movement of water, including the existence of vertical shear (where current speed changes with depth) and eddies (circular - shaped patterns of current).

5. What are requirements for high-quality measurement of Atlantic City coastal currents?

Reliability of materials is needed for high-quality measurement of the coastal currents off Atlantic City. Because of the corrosive nature posed by saltwater, the ADCPs and other equipment have to be made of corrosion-resistant materials. This titanium alloy is an excellent material for ADCP housings. Titanium is also very resistant to corrosion, guaranteeing the equipment's durability. This minimizes the necessity for constant replacements, which is particularly crucial for long-term monitoring projects.

Size and weight are also important considerations. Small and light ADCPs are easier to deploy and transport, especially in the shallow and sometimes congested waters off Atlantic City. This is useful for field work since it is easier for researchers to transport the equipment to varied points of measurement.

Low power consumption is essential, particularly for extended observation. Since ADCPs are likely to be driven by batteries, low power components allow the instrumentation to function continuously for extended lengths of time without needing to swap batteries often. This is most important in the remote coastal environment or where proximity to power may be restricted.

Cost - effectiveness is an important consideration, particularly for large - scale monitoring projects. Cheap but reliable ADCPs are very much sought after. Companies such as China Sonar PandaADCP provide a satisfactory compromise between cost and performance. Constructed of all - titanium alloy, it offers robustness in the tough marine environment without being too costly.

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

Equipment choice for real - time measurement in the area around Atlantic City will depend on the specific application. Ship - mounted ADCPs are well suited to wide - scale surveys. They can be mounted aboard research ships and be measuring the currents continuously while the ship moves down the coast and into Absecon Bay. This provides a broad - scale picture of the pattern of currents in the area.

Bottom - mounted or moored ADCPs are ideally suited for fixed - location, long - term monitoring. They can be installed on the seafloor or bay bottom off Atlantic City and supply current data for months or even years. This helps to examine long - term trends in coastal currents.

Buoy-mounted ADCPs are well suited for surface-level current measurement. They are simple to deploy and recover, making them appropriate for short-term studies or for a quick assessment of surface-current conditions.

In choosing an ADCP, frequency is important. For depths to 70m, a 600kHz ADCP would be adequate. It has appropriate resolution for measuring currents in the comparatively shallow coastal and estuarine waters along Atlantic City. For waters to 110m deep, a 300kHz ADCP would be sufficient, and a 75kHz ADCP for deeper waters, to 1000m. Lower frequency penetrates deeper but lower resolution than higher frequency.

There are several established ADCP brands out there, such as Teledyne RDI, Nortek, and Sontek. However, for the price-sensitive individual who doesn't wish to compromise on quality, the ADCP supplier China Sonar's PandaADCP is a good choice. More details can be found on its website: https://china-sonar.com/.

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