The international Argo program is widely recognized as the “gold standard” in global ocean observation systems, especially because of its ability to deliver freely available and accurate data to the science community and end user clients. This does not mean that the Argo program has no challenges to address. As with any sustained Earth observation system there is continuous pressure to increase efficiency, and to find ongoing funding to maintain the global array. Over the last several years, the Argo Steering Team (AST) has been discussing what needs to be done to ensure the long-term sustainability of the Argo program. The move towards integrating new biogeochemical sensors, and deep-profiling floats, into the array makes addressing these needs all the more important as the system becomes more complex. One key element that has been identified by the AST to address sustainability is to improve the level of technical expertise in countries that are deploying Argo floats. The goal is to improve pre-deployment testing and checks to minimize early failures of floats. Also, improved at-sea procedures can help to improve float lifetimes. If we can improve the average lifetime of Argo floats in the ocean, then Argo will have to deploy fewer floats annually to maintain the density goals of the array.

A three-day workshop was held at Ifremer in Brest, France on 28-30 January 2020 with 58 attendees. This workshop was organized by Argo Canada and Argo France for Arvor-Provor Argo float users with the objective of improving the level of technical expertise and to share best practices. In addition to scientists and technicians that deploy floats, the workshop also included representatives of the Argo data management community, and the Arvor/Provor float manufacturer (NKE) and sensor providers (Sea-Bird, RBR, JFE). The format of the workshop combined classroom presentations and discussions with hands-on training at the Ifremer test tank.

Day 1 of the workshop began with an overview of previous float technical workshops held at the University of Washington, with a summary of lessons learned. This was followed by a presentation on the status of the Arvor and Provor floats in the context of the global Argo array and included a discussion of the lifetime and performance of these platforms. The potential to support new scientific research initiatives was highlighted in presentations on the Provor biogeochemical float and the Deep-Arvor platform. In the afternoon, the Arvor/Provor manufacturer (NKE) provided the workshop attendees with an overview of the company and its various products along with information on customer support. This was followed by presentations on float sensors by RBR, NKE and JFE. The day finished with a presentation on new technical developments for the Provor CTS5 at LOV, and an update on Argos and Iridium communications from CLS.

Day 2 began with a presentation from Sea-Bird on the various sensors that the company provides for Argo floats along with information on best practices for handling, storage and preparation of BGC sensors. This was followed with an update on two Ifremer R&D projects, one to incorporate an ADCP on a Deep-Arvor and the second on the 3-head Deep-Arvor with the SBE41, SBE61 and RBR CTDs mounted on a float. The remainder of the morning focussed on best practices for both floats and sensors as well as metadata and data management. In the afternoon, workshop attendees had the chance to get some hands on experience with floats at the Ifremer test tank facility. This aspect of the workshop was very well received given the interactive nature of the activity, and lots of discussion was generated.

The morning of Day 3 provided an overview of the Argo file structure at the Global Data Assembly Centres (GDAC), naming conventions, file types, etc. An introduction to the R oce package provided attendees with information on how to visualize Argo data from GDAC NetCDF files with minimal effort or training required. A presentation of the Euro-Argo online fleet monitoring tool was demonstrated to show how this can be used to access technical information on all floats in the global array; this tool is an excellent complement to the JCOMMOPS application for the Argo program. In the afternoon of Day 3, two case studies (float recovery, under ice behaviour) were presented as well as an introduction to the Provor CTS5 graphical user interface for mission planning. The workshop concluded with a discussion about key issues and potential recommendations generated over the preceding three days.

All the materials from the workshop are available online at: https://github.com/euroargodev/techworkshop

By the organizing committee:

• Noé Poffa (Ifremer, France)
• Blair Greenan (DFO, Canada)
• Antoine Poteau (LOV, France)
• Guillaume Maze (Ifremer, France)