The autonomous submarine to be housed on the UK's new Antarctic research vessel, RSS Sir David Attenborough, has shed light on a key process linking increasing Antarctic winds to rising sea temperatures.
The Autosub Long Range (better known as Boaty McBoatface after the phrase won a competition to name the research vessel, but the government deemed it too silly) undertook the research in September 2017 as part of its first research voyage, in a project involving the British Antarctic Survey, Southampton University, and US institutions Princeton University and Woods Hole Oceanographic Institute. Its mission took it on a 180 mile (290km) journey through underwater valleys, navigating via echo sounding, where it measured such data as water turbulence using a Doppler current profiling instrument and shear micro structure sensors, plus salinity and temperature.
Reaching depths of 4000m, Boaty was eventually recovered by another research vessel, RSS James Clark Ross (RSS Sir David Attenborough is currently undergoing sea trials ahead of its active service) and its data downloaded for study.
The following video (courtesy of Povl Abrahamsen) shows highlights of the voyage of McBoatface.
In a paper published in Proceedings of the National Academy of Sciences, the Southampton team, led by Prof Alberto Navaeiro Garabato, explained that the data revealed a link between wind levels over the Southern Ocean and rising sea temperatures. In recent decades, ozone depletion over Antarctica combined with increasing greenhouse gas levels have led to the strength of these winds increasing, the team says, and the data from the submarine has revealed a mechanism that allows these winds to increase turbulence deep below the surface of the ocean, causing warmer water from the mid-levels of the sea to mix with far colder water deep in the abyss.
This effect was not previously built into models for predicting the impact of rising global temperatures on the oceans, and the team believes it has made a significant contribution to rising sea levels. "Our study is an important step in understanding how the climate change happening in the remote and inhospitable Antarctic waters will impact the warming of the oceans as a whole and future sea level rise," Garabato said.
The research reveals the utility of autonomous vessels such as Boaty, added Povl Abrahamsen of the British Antarctic Survey: "This study is a great example of how exciting new technology such as the unmanned submarine "Boaty McBoatface" can be used along with ship-based measurements and cutting-edge ocean models to discover and explain previously unknown processes affecting heat transport within the ocean."