https://phys.org/news/2018-10-marine-robots-european-weather-future.html

The scientific instruments that comprise the RAPID array are deployed on 'moorings', wires that extend from an anchor on the seafloor, sometimes more than 5km deep, to just below the sea-surface. A new unit, developed at the NOC's laboratories in Southampton and Liverpool, will be attached to one of these moorings to gather data from all the instruments on the wire and then transmit the data using sound signals to a marine robot called a "Wave Glider" at the sea surface, which will in turn send the data by satellite to scientists at the NOC.

                
            
        
        
    
    The Waveglider autonomous vehicle that will be used on this expedition. Credit: National Oceanography Centre (NOC)

"This new system will enable us to get data that could in the future improve seasonal weather forecasts for Europe", says project scientist Darren Rayner from the NOC. "The system has successfully completed a short trial in water 600m deep, but an 18-month deployment in water 4,000m deep is a much tougher test"