Biogeochemical sensor performance in the SOCCOM profiling float array

Type Article
Date 2017-08
Language English
Author(s) Johnson Kenneth S.1, Plant Joshua N.1, Coletti Luke J.1, Jannasch Hans W.1, Sakamoto Carole M.1, Riser Stephen C.2, Swift Dana D.2, Williams Nancy L.3, Boss EmmanuelORCID4, Haentjens NilsORCID4, Talley Lynne D.5, Sarmiento Jorge L.6
Affiliation(s) 1 : Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA.
2 : Univ Washington, Sch Oceanog, Seattle, WA 98195 USA.
3 : Oregon State Univ, Coll Earth Ocean & Atmospher Sci, Corvallis, OR 97331 USA.
4 : Univ Maine, Sch Marine Sci, Orono, ME USA.
5 : Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA.
6 : Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA.
Source Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2017-08 , Vol. 122 , N. 8 , P. 6416-6436
DOI 10.1002/2017JC012838
WOS© Times Cited 91
Note This article also appears in: The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project: Technologies,
Keyword(s) profiling floats, oxygen sensors, pH sensors, nitrate sensors, bio-optical sensors, Southern Ocean
Abstract

The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) program has begun deploying a large array of biogeochemical sensors on profiling floats in the Southern Ocean. As of February 2016, 86 floats have been deployed. Here the focus is on 56 floats with quality-controlled and adjusted data that have been in the water at least 6 months. The floats carry oxygen, nitrate, pH, chlorophyll fluorescence, and optical backscatter sensors. The raw data generated by these sensors can suffer from inaccurate initial calibrations and from sensor drift over time. Procedures to correct the data are defined. The initial accuracy of the adjusted concentrations is assessed by comparing the corrected data to laboratory measurements made on samples collected by a hydrographic cast with a rosette sampler at the float deployment station. The long-term accuracy of the corrected data is compared to the GLODAPv2 data set whenever a float made a profile within 20 km of a GLODAPv2 station. Based on these assessments, the fleet average oxygen data are accurate to 1 +/- 1%, nitrate to within 0.5 +/- 0.5 mu mol kg(-1), and pH to 0.005 +/- 0.007, where the error limit is 1 standard deviation of the fleet data. The bio-optical measurements of chlorophyll fluorescence and optical backscatter are used to estimate chlorophyll a and particulate organic carbon concentration. The particulate organic carbon concentrations inferred from optical backscatter appear accurate to with 35 mg C m(-3) or 20%, whichever is larger. Factors affecting the accuracy of the estimated chlorophyll a concentrations are evaluated.

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Johnson Kenneth S., Plant Joshua N., Coletti Luke J., Jannasch Hans W., Sakamoto Carole M., Riser Stephen C., Swift Dana D., Williams Nancy L., Boss Emmanuel, Haentjens Nils, Talley Lynne D., Sarmiento Jorge L. (2017). Biogeochemical sensor performance in the SOCCOM profiling float array. Journal Of Geophysical Research-oceans, 122(8), 6416-6436. Publisher's official version : https://doi.org/10.1002/2017JC012838 , Open Access version : https://archimer.ifremer.fr/doc/00662/77398/