| Summary: | Progress Code: onGoing Statement: Caution: Fluorometry is measured differently on each vessel and are thus not directly comparable between vessels. Most values come from Turner fluorometers. The Aurora Australis has a Turner TD10, and the units are arbitrary even though the fluorometer is routinely calibrated. Further, a value of 200 on one voyage is not necessarily the same as 200 on another voyage, even with daily calibration and cleaning of the sensor. The fluorometry values are really only of value within a voyage in as much that 200 is double the fluorescence activity of 100. On Tangaroa and Kaiyo Maru, fluorometry has been expressed as a concentration of chlorophyll a. There doesn't seem to be any fluorometry data for Hakuho Maru. Notes on salinity: The salinity measurement comes from the various thermosalinograph units mounted in the underway systems of the ships. Salinity on the Aurora Australis has been calculated by thermosalinograph. Salinity values are expressed in practical salinity units. Notes on water temperature: Temperature on the Aurora Australis is measured by a high resolution thyristor near the entrance of a dedicated seawater line, to avoid the problems of heating of the water in by the ship as it passes through pipes. Again the data may not be fully comparable with other vessels. Notes on segment length: The end of each sampling segment is geocoded with latitude and longitude calculated from the one minute time-stamped GPS data. 'Segment Length' is the distance in nautical miles for each segment, which is calculated as the cumulative distance between each 1 minute interval. In theory, all segments are 5 nautical miles long. However, this wasn't always the case with early RSV Aurora Australis tows, where it was assumed that the silks advanced at a predetermined rate of 1 cm per nautical mile, whereas each tow had subtle variations in silk advancement, depending on local condition, e.g. whether the CPR was travelling with or against a current. True segment length has since been ...
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