Current measurement expeditions: Deep-sea, shelf-edge, near-surface, shallow-water, and under ice

Development of a velocity measurement technology in science is driven by questions requiring the new technology for their answers. Thus application of the new technology is the only reason for its development and expeditions using it are the test of its behavior. Yet from an engineering viewpoint, the expeditions are simply testing milestones on the development path. This paper is tutorial to a degree to explain to less battle scarred oceanic engineers why and how development of instrumentation proceeds.