Journal Article

Correction and Accuracy of High- and Low-Resolution CTD Data from Animal-Borne Instruments

Picard, Baptiste, Department of Marine Sciences [Gothenburg] ; Göteborgs Universitet = University of Gothenburg (GU), Institute of Low Temperature Science [Sapporo] ; Hokkaido University [Sapporo, Japan], Mensah, Vigan, Jet Propulsion Laboratory (JPL) ; NASA-California Institute of Technology (CALTECH), Department of Environmental Science and Engineering [Pasadena] (ESE) ; California Institute of Technology (CALTECH), CNES-TOSCA IPEV CORIOLIS in situ ocean observation program CNES LabexMer doctoral fellowship, Guinet, Christophe, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) ; Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR) ; Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Rivière, Pascal, Siegelman

2019

Overview

Most available CTD Satellite Relay Data Logger (CTD-SRDL) profiles are heavily compressed before satellite transmission. High-resolution profiles recorded at the sampling frequency of 0.5 Hz are, however, available upon physical retrieval of the logger. Between 2014 and 2018, several loggers deployed on elephant seals in the Southern Ocean have been set in continuous recording mode, capturing both the ascent and descent for over 60 profiles per day during several months, opening new horizons for the physical oceanography community. Taking advantage of a new dataset made of seven such loggers, a postprocessing procedure is proposed and validated to improve the quality of all CTD-SRDL data: that is, both high-resolution profiles and compressed low-resolution ones. First, temperature and conductivity are corrected for a thermal mass effect. Then salinity spiking and density inversion are removed by adjusting salinity while leaving temperature unchanged. This method, applied here to more than 50 000 profiles, yields significant and systematic improvements in both temperature and salinity, particularly in regions of rapid temperature variation. The continuous high-resolution dataset is then used to provide updated accuracy estimates of CTD-SRDL data. For high-resolution data, accuracies are estimated to be of +/- 0.02 degrees C for temperature and +/- 0.03 g kg(-1) for salinity. For low-resolution data, transmitted data points have similar accuracies; however, reconstructed temperature profiles have a reduced accuracy associated with the vertical interpolation of +/- 0.04 degrees C and a nearly unchanged salinity accuracy of +/- 0.03 g kg(-1).

• Publisher: American Meteorological Society,CCSD
• Subject: [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] / [SDE.BE]Environmental Sciences/Biodiversity and Ecology / [SDU.OCEAN]Sciences of the Universe [physics]/Ocean / [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere / Accuracy / ACL / Algorithms / Ascent / Atmosphere / Biodiversity and Ecology / Calibration / Data / Data loggers / Data points / Data processing / Datasets / Engineering / Environmental Sciences / Geophysics / High resolution / In situ oceanic observations / Instruments / Interpolation / Marine mammals / Meteorology & Atmospheric Sciences / Ocean, Atmosphere / Oceanografi, hydrologi och vattenresurser / Oceanography / Oceanography, Hydrology and Water Resources / Oceans / Parameter estimation / Physical oceanography / Physics / Profiles / Recording / Resolution / Salinity / Salinity effects / Satellite transmission / Satellite-borne instruments / Satellites / Sciences of the Universe / sea / Seals / Sensors / Temperature effects / Temperature profile / Temperature profiles / Temperature variations
• ISBN: 0004653895000