Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Ocean Sci., 13, 649-660, 2017
https://doi.org/10.5194/os-13-649-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
04 Sep 2017
A measurement system for vertical seawater profiles close to the air–sea interface
Richard P. Sims1,2, Ute Schuster2, Andrew J. Watson2, Ming Xi Yang1, Frances E. Hopkins1, John Stephens1, and Thomas G. Bell1 1Plymouth Marine Laboratory, Plymouth, UK
2University of Exeter, Exeter, UK
Abstract. This paper describes a near-surface ocean profiler, which has been designed to precisely measure vertical gradients in the top 10 m of the ocean. Variations in the depth of seawater collection are minimized when using the profiler compared to conventional CTD/rosette deployments. The profiler consists of a remotely operated winch mounted on a tethered yet free-floating buoy, which is used to raise and lower a small frame housing sensors and inlet tubing. Seawater at the inlet depth is pumped back to the ship for analysis. The profiler can be used to make continuous vertical profiles or to target a series of discrete depths. The profiler has been successfully deployed during wind speeds up to 10 m s−1 and significant wave heights up to 2 m. We demonstrate the potential of the profiler by presenting measured vertical profiles of the trace gases carbon dioxide and dimethylsulfide. Trace gas measurements use an efficient microporous membrane equilibrator to minimize the system response time. The example profiles show vertical gradients in the upper 5 m for temperature, carbon dioxide and dimethylsulfide of 0.15 °C, 4 µatm and 0.4 nM respectively.

Citation: Sims, R. P., Schuster, U., Watson, A. J., Yang, M. X., Hopkins, F. E., Stephens, J., and Bell, T. G.: A measurement system for vertical seawater profiles close to the air–sea interface, Ocean Sci., 13, 649-660, https://doi.org/10.5194/os-13-649-2017, 2017.
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Short summary
This paper describes a near-surface ocean profiler (NSOP) that is deployed from a research vessel. The NSOP is used to sample the top 10 m of the ocean and pumps water back to the research ship for scientific analyses such as for trace gases. The precision in the depth of the seawater collection improves upon previous methods. The NSOP has been used to observe vertical gradients in the upper 5 m for temperature, carbon dioxide and dimethylsulfide.
This paper describes a near-surface ocean profiler (NSOP) that is deployed from a research...
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