Figure 1: the MOD refractometer

We believe that by constant tinkering, labs like ours will stumble upon new and novel means of sensing.  A partly-successful example was a refractometer we built some time ago, which sensed index of refraction on 1-mm scales (Figure 1).  Using technology modified from AIDS research, we developed a sensor half the diameter of a human hair to sense these smallest-scale fluctuations in ocean refractive index. These are closely related to salinity fluctuations, which to-date have been measured by conductivity and temperature measurements. Measuring salinity from one small sensor reduces "spiking" resulting from mismatched sensor responses. 

Figure 2: Distributed Temperature Sensing (DTS) system

Figure 2: Distributed Temperature Sensing (DTS) system

A novel technology that has been under-exploited in the ocean is called Distributed Temperature Sensing, wherein back-scattering from laser pulses sent down a fiber are monitored versus range along the fiber.  Because the so-called Raman scattering depends on temperature, profiles of temperature along the fiber are given.  The continuity of the data in both time and distance allows for extremely high-resolution picture of high-frequency ocean processes to be gained, such as along the continental shelf near San Diego (Figure 2).

Who knows what will be next, but our platforms will be ready to record the signals.  Next-generation sensors like these result in part from hard work and creativity from our undergraduate interns we have in our lab every summer.