The ocean has a very important role in the global climate system, where there are oceanographic parameters such as currents, temperature, salinity, and others that are interconnected and interact with each other in determining the dynamics of the water column. The water column is a layer of water that stretches from the surface to the bottom of the water. The relationship between these parameters is crucial in understanding the processes that occur in the ocean, such as water mass circulation, biological productivity, and solute dispersion patterns. Tethered Profilers are a very effective tool for measuring these parameters vertically along the water column. Tethered Profilers are equipped with sensors capable of detecting current, temperature, salinity, and other parameters with high resolution, providing detailed and integrated data. This profiling allows scientists to study the relationship between temperature changes and salinity with water density, which affects the circulation of thermohaline currents. In addition, currents also play a role in carrying nutrients from the sublayer to the surface through the upwelling process, which has an impact on primary productivity in the sea. Tethered Profilers are oceanographic devices that are commonly used to measure the characteristics of water columns, including current, temperature, salinity, and other parameters. It works and moves up and down or vertically along cables (tethers) connected to fixed platforms such as ships, buoys, or seabed structures. This obtained movement can allow for a compact profile of various depths in the water column. The data obtained supports an understanding of physical processes such as upwelling and thermocline, as well as global phenomena such as climate change and marine ecosystem dynamics. Tethered Profilers are highly effective in providing high vertical resolution, making them an essential tool for marine exploration and environmental research.
Main Components:
- Tether Cable: Serves as a line for data and power communication.
- Profiling Unit: The main module equipped with sensors to measure oceanographic parameters such as current, temperature, and salinity.
- Current Sensors: It typically uses acoustic technology such as the Acoustic Doppler Current Profiler (ADCP) or electromagnetic sensors to measure the speed and direction of the current.
- Communication System: Transmits data to a processing platform, either via cable or wireless transmission.
How Tethered Profilers Radar Work
Tethered Profilers work by lowering or raising the unit of measurement along the tether cable using a motor or passive mechanism. When the device moves, the sensors inside it pick up current data at a certain depth.
- Current Measurement: Acoustic sensors such as ADCP measure the Doppler shift of the sound signal reflected by particles moving in the water. It provides information about the speed and direction of the current.
- Profiling Data: Data is taken vertically from the surface layer to the seafloor (or the maximum allowable depth). This data is then used to build a current profile based on depth.
Working Steps:
- Preparation and Installation
- Tethered Profilers instruments are mounted on cables (tethers) connected to fixed platforms, such as marine buoys, research vessels, or underwater structures.
- The main sensors (such as temperature, salinity, and current) are calibrated in advance to ensure measurement accuracy.
- Determination of Profiling Depth
- The maximum depth to be measured is determined based on the length of the tether cable and the characteristics of the research area.
- Profiling Operation
- Profilers move up or down vertically along the tether cable, either through an automatic motor mechanism or a passive system that utilizes gravity and buoyancy.
- During movement, the sensors on the instrument continuously measure oceanographic parameters, such as temperature, salinity, current, dissolved oxygen, and more
- Data Collection
- The data measured by the sensor is transmitted in real-time via a tether cable to the controller platform or a local storage device in the instrument.
- This data includes parameter measurements at various depths, resulting in a vertical profile of the water column.
- Profiling Repeatability
- Profilers can be programmed to perform repeated measurements at specific time intervals (e.g., hourly or daily), depending on the needs of the study.
- These repetitive measurements help to dynamically monitor changes in water column parameters.
- Data Processing and Analysis
- The data obtained were analyzed to study the relationship between parameters, such as the influence of temperature and salinity on water density or the relationship of current with nutrient distribution.
- The results of the analysis are used for further research, such as modeling current circulation or monitoring changes in the marine environment
- Maintenance and Recalibration
- After the operation is complete, the instrument is checked and recalibrated to ensure the sensor remains in optimal function. Tether cables are also inspected to prevent damage due to corrosion or biological disturbances such as attached marine plants.
Tethered Profilers strengths and weaknesses
Strengths
- High vertical resolution: Provides detailed data on current variations along the water column.
- Long-term operation: Can be used for weeks or months with an automated system.
- Easy to adjust: Can be set to measure additional parameters such as oxygen levels, chlorophyll, or turbidity.
Weaknesses
- Depth limitations: Depends on the length of the tether cable.
- Interference by waves: In the open sea, wave conditions can affect the stability of the device.
- Regular maintenance: Tether cables require maintenance to prevent damage due to corrosion or biological disorders
Writer : Talitha Aprillia Ensu
