Gulf of Mexico Technology Demonstration

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Fiber optic distributed sensors. Image courtesy of the Gulf of Mexico Technology Demonstration. . Download larger version (jpg, 6.1 MB).

As part of the Gulf of Mexico Technology Demonstration on board NOAA Ship Okeanos Explorer, novel temperature profiling and acoustic array acquisition methods are being tested using fiber optic sensing through a collaboration between the Global Foundation for Ocean Exploration, the Center for Transformative Environmental Monitoring Programs, and Silixa.

Temperature and acoustic data will be collected from a 1,300-meter (4,265-foot) fiber optic tow cable using distributed temperature sensing (DTS) and distributed acoustic sensing (DAS). DTS allows for measurement of temperature at all locations along a fiber optic cable simultaneously, with sub-meter spatial resolution. Temperature profiles can be recorded as rapidly as every few seconds, and for longer measurement times, temperature resolution can be as fine as 0.01°C.

The temperature profiling method will help provide a detailed understanding of temperature distributions with depth and will allow for measurement of dynamic processes that cannot be captured using alternative techniques. In addition to DTS, DAS can act as a continuous array of hydrophones with the potential to monitor acoustics (sound) from a towed array. Both techniques are being simultaneously tested using multiple optical fibers within the tow cable.

Major goals for this technology demonstration are:

1. To understand tow cable behavior and effects on the integrated optical fibers
2. To test multiple DTS calibration techniques to allow for optimized DTS measurements to be collected
3. To determine the performance of DAS on a towed cable
4. To evaluate the spatio-temporal temperature data when compared to traditional measurement techniques
5. To identify improvements that can be made to the deployment methods and system hardware

Analyses of the datasets will provide a baseline understanding of incorporating distributed sensing into towed cables and will demonstrate the capability of the techniques for oceanographic purposes.

Towed cable array the night of March 31. 2018. Image courtesy of the Gulf of Mexico Technology Demonstration. . Download larger version (jpg, 6.3 MB).