New K2 Temperature Sensor for Ocean Mobile Platforms

Recent research has shown that microstructure mixing events, especially those associated with temperature and salinity variations, can pose significant influences to underwater optical and acoustical signal propagation. Under certain conditions, such influences can become a limiting factor.

In the process of quantifying microstructure mixing events in the ocean, we developed a new class of fiber-optics based sensors that exploits the high sensitivity and dynamic range of the Fabry-Perot interferometry setup. Specifically, we have demonstrated an accuracy on the order of 0.001 DegC, at a sampling rate of 1kHz, spanning a dynamic range of 10+ DegC. Laboratory experiments in a controlled environment, where turbulence mixing intensities can be regulated and are guided by a numerical model as well as monitored by measurements, have confirmed the sensor capabilities. Due to the absence of comparable high speed sensors in this class, an indirect confirmation has been used through comparing temperature gradient spectra from the new sensor with those from a microstructure thermistor, and the results demonstrate a noted improvement in noise reduction at higher frequencies. Initial field testing of the compact, self-contained version of the sensor package showed that the data is consistent with concurrent CTD measurements. Uncertainties and improvement paths have been identified and discussed. Future plans and potential applications are open for input.