CTDs and ADCPs

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I have been looking at pictures of this ship for a couple of months now, and now I’m actually on it. It actually took several hours (as you saw from the last post) to lift all the equipment and cargo onboard by crane. As they were moving the cargo onboard, I walked around with some of the scientists (being careful not to be under the crane at any point), and started to learn about some of the equipment (not to mention acronyms) that I have been hearing about.

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Here is a rosette with CTD and ADCP. What does that mean? CTD stands for Conductivity, Temperature, and Depth, and ADCP stands for Acoustic Doppler Current Profiler. And what does that mean? This collection of instruments is for sampling water. By dropping this into the water, or “casting,” scientists can take samples of water at several different depths. The vertical grey tubes around the rosette (the white caging) are pressurized such they each will take in water at a given pressure (which corresponds to depth). The CTD measures the conductivity (i.e. related to the salt conduct, or salinity, of the water), temperature, and depth (i.e. the pressure) at that point. The ADCP device puts out a “sounding” and uses acoustics to measure the current of the water at that point. On this rosette, there are multiple ADCPs, in order to measure the current in different directions. This instrument allows scientists to analyze an entire “column” of water, down to extreme depths – I don’t know yet how deep this one can go, but some instruments of this kind can go miles (or more) down!

But here’s something to remember – if you’re the person collecting these samples on the surface, your fingers are going to hurt afterward, from handling the incredibly cold knobs and canisters, not to mention the water pouring out. (P.S. It’s unseasonably warm here so far, but it’s going to get a lot colder real quick!)

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