Autonomous and Lagrangian Platforms and Sensors: A Scientific and Technical Review

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

Observational oceanography involves the sampling of a global turbulent fluid. Relevant length scales range from the size of ocean basins down to the millimeters where turbulent dissipation occurs. Time scales of interest are as small as seconds to climate fluctuations of decades or centuries. A relatively new approach to address the challenges of sampling this broad range of scale is to use autonomous platforms, defined here as being unconnected either to a ship or the seafloor. The trends in autonomous and Lagrangian platforms and sensors (ALPS) have been apparent for some time. This recognition led to the initial NSF-sponsored ALPS workshop in 2003 and it is timely to revisit its findings. In 2003, the Argo array had only 900 floats on its way to the current array of more than 3500. Underwater gliders were being developed, but no real science had been done with them yet. Propeller-driven AUVs were beginning to deliver results. A wide range of biogeochemical sensors was discussed at the meeting, mostly as possibilities, although there were some results from floats. Many of the predictions in the ALPS report have proven to be accurate, with a marked increase in the number of scientists using autonomous platforms to address research problems. The ALPS-II meeting will take place at the Scripps Institution of Oceanography, during 21-24 February 2017.The outcome of ALPS-II will be broadly shared with the ocean scientific community. In pursuit of this objective, the meeting will be as open as possible subject to the limited number of on-site participants. A website will make publically available all meeting materials, including the final report. The plenary sessions will be broadcast on the internet. Importantly, all workshop participants will be encouraged to consider the interests of the broader community in their contributions. Meeting recommendations are expected to include means to make ALPS technologies accessible to more scientists. If fully successful, the results of the meeting will be a catalyst towards the adoption of ALPS widely throughout the ocean community, both for research and operations. This second ALPS science and technology review has the overarching goals (1) to survey progress in the past 13 years, and (2) to assess future prospects. The meeting will examine the ALPS enterprise through a sequence of slices through a rapidly growing field. The history and potential of the various platforms (drifters, floats, gliders, autonomous underwater vehicles, autonomous surface vehicles, unmanned aerial vehicles) will be addressed. The various classes of sensors including physical, biogeochemical, optical, acoustic, etc. will be reviewed with special attention to their use on autonomous platforms. The scientific problems amenable to ALPS technologies will be discussed including global and regional issues, high latitudes, ocean acidification, and climate variability. The value of ALPS in ocean forecasting will be a topic of interest, including approaches for adaptive sampling and control. Models for managing and operating ALPS assets will be discussed, with the goal of making the technologies available to more scientists. This brief list of topics is neither exhaustive nor prescriptive, as meeting participants will have latitude to guide the meeting.