Remembering SAEON’s Argo floats

By Jethan d’Hotman, Tamaryn Morris, Juliet Hermes and Thomas Mtontsi, SAEON Egagasini Node Tweet

In December 2009, SAEON, in collaboration with the South African National Antarctic Programme (SANAP) deployed two Argo floats, which marked the launch of the South African Argo Program.

These Argo floats were deployed during the South African National Antarctic Expedition (SANAE) 48 from the SA Agulhas. The two Argo floats (1901469 and 1901470) were deployed in the Southern Ocean along the Good Hope line.

Figure 1. Trajectories of the two SAEON Argo floats. Black stars indicate deployment position.

The first Argo float (1901469) had a relatively short life of 15 months, and was deployed in the core of the Antarctic Circumpolar Current (Figure 1). The Argo float completed 47, 10-day cycles; 103 cycles short of the 150 global average before becoming grounded at Marion Island.

Epic journey

The second Argo float (1901470), deployed further north, has been collecting valuable temperature and salinity data in the Agulhas Current’s Retroflection region. This Argo float must have somehow received the news that its sister float (1901469) had been grounded because it went on to complete 246 cycles (lasting more than seven years), making up for those profiles the first Argo float did not complete. This float made an epic journey circling around the Agulhas Current and through the South Indian Ocean before dying just a short distance away from the shores of Western Australia.

The four Argo floats adopted by schools supported by the SAEON Egagasini Node.

Environmental science education outreach

The data from these Argo floats has been used in a number of secondary and tertiary education projects. Most recently the SAEON Egagasini Node used the data to educate several high school learners about various methods of marine data collection.

A learner writes the name of her school on an Argo float while SAEON’s Thomas Mtontsi (left) and Jethan D’Hotman look on.

The data has also been analysed in two National Diploma and BTech student projects supervised by Tamaryn Morris and Juliet Hermes. Additional newsletter articles have been written about Argo and South Africa’s Argo floats, most notably by Juliet Hermes about South Africa’s invitation onto the Argo Steering Team in 2011. More recently Tamaryn Morris reminded readers of the Argo program, South Africa’s involvement and the best places to deploy Argo floats around the South African coast.

South Africa continues to have an active Argo program focused around outreach and assisting other countries’ Argo programs to deploy Argo floats from South African research cruises. More recently the SAEON Egagasini Node pioneered an Adopt-a-Float programme where high schools are given the opportunity to adopt an Argo float. SAEON’s education team then visits the schools and teaches learners about the ocean and analysing the data ‘their’ Argo float has collected.

Over the next few years the South African Argo community is hoping to grow the Argo program substantially by expanding the Argo float family and data management thereof.