Swallow float

{
  "id": "MLC-T-MET-010803",
  "term": "Swallow float",
  "field": "Meteorology and atmospheric science",
  "definition": "A neutrally buoyant, free-drifting instrument used to measure subsurface ocean currents. The float, a sealed aluminum tube, is weighted to sink to a predetermined depth where its density matches the surrounding seawater, after which it drifts with the local current. Its position is tracked acoustically by a surface vessel to determine the speed and direction of water movement at that depth.",
  "url": "https://mlchart.com/terminology/meteorology/swallow-float/"
}