Offshore Demonstration of an Unmanned Surface Vehicle for Autonomous Hypoxia Monitoring

A partnership led by the University of Southern Mississippi has been funded by the National Oceanic and Atmospheric Administration's Integrated Ocean Observing System as an Ocean Technology Transition Project, to accelerate the transition of adaptive, autonomous water quality profiling capabilities for a work-class uncrewed surface vehicle, to collect near bottom profile data in the context of other physical parameters and develop a framework for transitioning the technology to operations. The transitioned technology will contribute to the characterization of Northern Gulf of Mexico hypoxia events. The public-private partnership includes the Gulf of Mexico Coastal Ocean Observing System, Integral Consulting, and L3Harris/ASV. The specific objectives of the project are to operationally demonstrate: 1.Autonomous water quality profiling capability for University of Southern Mississippi's and L3Harris ASV“s C-Worker 5 work-class uncrewed surface vehicle to conduct water column profiles to measure stratified waters in depths from 5 m to over 50 m and bottom observations adaptively to within 1 m above the sediment bed. 2.Real-time transmission of data relevant to hypoxia monitoring to support northern Gulf of Mexico hypoxic zone surveys and modeling; data will be made free and publicly available through operational data centers. In Year 1 of the project L3Harris/ASV integrated an altimeter with the winch controller of the C-Worker 5, integrated a conductivity, temperature and depth sensor package with dissolved oxygen sensor and altimeter with a computer data logger, and built a launch and recovery system for the sensor package. The integration of the altimeter with the winch controller allows the sensor package to be lowered within 1 m of the seafloor, and this was successfully tested in a lake. During Years 1 and 2 of the project, Integral Consulting built a data management system that accepts an ftp connection from the vessel (over cell service in this demo), downloads cast files and metadata, performs quality control checks, and bundles the data and metadata into netcdf files. The Gulf of Mexico Coastal Ocean Observing System set up a system to download the netcdf files and display the location of the vessel and the data on their GANDALF platform. In Year 2 an offshore demonstration of the system was conducted. On October 6th and 7th of 2022, day-cruises were conducted offshore of Mississippi with the C-Worker 5 of the University of Southern Mississippi sampling a set of stations that included those from a project that ran a quasi-monthly offshore transect from 2011- 2015, and for which seasonal seafloor hypoxia was found each year of that project. Although delays pushed the demonstration past hypoxia season, at each station the vessel was able to profile to within 1 m of the seafloor. Nearby profiles were taken from an observation boat, the USM R/V Jim Franks, for validation. The data management plan was successfully tested from observations, to telemetry to shore based servers, to data QC and netcdf file generation by Integral Consulting to download by GCOOS.