Bringing oceanographic current measurement out in the open

Abstract:

Here we present our efforts in bringing scientific-grade oceanographic current measurement technology within the reach of STEM programs and Citizen Scientists.

More than 40% of the world’s population lives within 100 km of the coast, and accurate knowledge of current circulation is arguably the most important aspect in advancing our understanding of our coastal oceans. The now ubiquitous Acoustic Doppler Current Profiler (ADCP) has since the early 1980s become one of the most widely used scientific instruments employed in expanding our understanding of the coastal ocean. Yet, despite being so widely used by the scientific and engineering communities, it is still far out of reach of the general public, STEM programs and Citizen Scientists. This is due to three primary factors: 1) high purchase cost, 2) complex system operation, including data presentation, and 3) challenges associated with safe deployment and retrieval of equipment. This inaccessibility excludes contribution to current prediction models by anyone outside of academia, government or well-funded, large-scale commercial companies.

Efforts by both commercial outfits as well as university programs over the last two decades have attempted to bridge this gap by developing simpler and lower cost alternatives (e.g. tilt current meters or propeller-based meters). However, these offer data from just a single depth rather than a full water column profile, do not provide three-dimensional current data, are often limited to a narrow range of current speeds, do not provide a public-facing data access solution, and, still do not overcome the challenges in deployment and retrieval, such as the need to use divers.

We describe the design and validation of a newly developed ADCP that is highly portable, low cost (factor of 3 reduction from a typical ADCP), has an embedded deployment and recovery solution so it can be used with minimal support (e.g. only a kayak), and requires no prior scientific or instrumentation experience to successfully collect high quality current profile data. Experience with users with previously no knowledge of ADCPs will be presented. In particular, work done by the Marine Megafauna Foundation in monitoring movement patterns of Giant Manta Rays in an inlet in Florida, USA, where detailed current data has not been previously available.