Half a cubic hectometer mooring array of 3000 temperature sensors in the deep sea

Abstract The redistribution of matter in the deep-sea depends on water-flow currents and turbulent exchange, for which breaking internal waves are an important source. As turbulence essentially three-dimensional ‘3D’, their dynamical development should ideally be studied a volume seawater. However, this is seldom done ocean where 1D-observations along single vertical line already difficult. We present design, construction successful deployment half-cubic-hectometer (480,000 m 3 ) 3D-T mooring array holding 2925 high-resolution temperature sensors to study weakly density-stratified waters 2500-m deep Western Mediterranean. stand-alone samples at rate 0.5 Hz, with precision <0.5 mK, noise level <0.1 mK expected endurance years. independent synchronized inductively every 4 h standard clock. consists 45 lines 125 long, 9.5 horizontally from nearest neighbor. Each held under tension 1.3 kN by buoyancy element that released chemically one week after deployment. All fold-up attached grid cables tensioned 70 diameter ring steel tubes. build-up harbor-waters, air filling tubes floatation. flat-form towed site favorable sea-state conditions. By opening valves tubes, sunk its free-fall controlled custom-made drag-parachute reducing average sinking speed s -1 providing smooth horizontal landing flat seafloor.