MOD is always working on new instruments to measure the ocean in novel ways. Recent advancements in integrated circuit technology (despite the global supply chain woes) have stoked increased interest, both within MOD and the oceanographic community at large, in taking complex measurements from autonomous vehicles. Although MOD is one of the world leaders in ocean mixing and turbulence measurements, in part because of our epsilometer technology, we have been limited to taking these measurements from research vessels. That all changed this February when MOD deployed the epsilometer on an autonomous platform for the first time. We collected 3 days of microstructure data (10 profiles over 700 vertical meters) off the coast of San Diego from an APEX Argo float.
A quick aside: the Argo program is one of the greatest collaborative efforts of global oceanography in human history. Member countries as diverse as South Africa, the US, Japan, and many more deploy autonomous floats of several varieties which measure a number of essential ocean variables across the top 2000 meters of the ocean. These floats last for many years and telemeter data over the Iridium satellite network, thus removing humans and expensive research cruises from the data collection process. All of this data is then made publicly available for ocean science and beyond.
Because they have extremely low-power and low-bandwidth requirements, APEX floats are heavily constrained on the instrumentation they can carry;. Until now, turbulence measurements have been too power- and bandwidth-hungry to collect from floats. MOD, through significant engineering effort and in collaboration with the float group at the University of Washington, has integrated an epsi sensor for turbulence measurements onto an APEX float. We deployed the first prototype from the R/V Bob and Betty Beyster on February 14th, 2022, recovered the float later that week, and are currently in the process of validating the data. This first test will inform the incoming on-board processing necessary for our sensor to become an off-the-shelf option for the Argo fleet. We plan to deploy more APEX-epsi floats later this year and are incredibly excited about enabling new frontiers in ocean science!
