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dc.contributor.authorBaker-Yeboah, Sheekela
dc.contributor.authorWatts, D. Randolph
dc.contributor.authorByrne, Deirdre A.
dc.date.accessioned2011-06-10T17:25:52Z
dc.date.available2011-06-10T17:25:52Z
dc.date.issued2009-12
dc.date.submitted2008-07
dc.identifier.issn0739-0572
dc.identifier.issn1520-0426
dc.identifier.urihttp://hdl.handle.net/1721.1/64409
dc.description.abstractVariability in sea surface height (SSH) can be decomposed into two contributions: one from changes in mass in the water column (barotropic) and the other from purely steric changes (baroclinic). Both contributions can be determined from data recorded by a pressure sensor–equipped inverted echo sounder (PIES). PIES data from the Agulhas South Atlantic Thermohaline Experiment (ASTTEX) were used, collected in the Cape Basin off South Africa, along 1000 km of an eddy corridor where Agulhas eddies carry cores of warm, salty Indian Ocean waters into the South Atlantic. The paper presents in detail the method used to convert PIES measurements into barotropic, baroclinic, and total SSH, and discusses the error budget. The baroclinic contribution is geopotential height (reference 4500 dbar), which can be determined from the measured vertical acoustic travel time together with a lookup curve based on the regional hydrography. The main error source is scatter about this curve that depends on the extent to which water masses advecting along each geopotential streamline may derive from different ocean regions. The barotropic contribution can be determined from the bottom pressure measurements of the mass variation in the water column and has an uncertainty due to sensor calibration drift in two years corresponding to 1-cm water column height. The barotropic component accounts for 20% of the overall SSH variance and 47% during large signal intervals exceeding 15 cm. PIES data demonstrate via the two measurements that barotropic and baroclinic contributions may work independently or in concert in different mesoscale eddies. The combined structure need not be equivalent barotropic. In particular, deep barotropic eddies exhibit mesoscale spatiotemporal scales and may or may not be systematically tilted or aligned in space or time relative to baroclinic eddies.en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant OCE-0095572)en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant OCE-0099177)en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant OCE-0221008)en_US
dc.description.sponsorshipUnited States. National Aeronautics and Space Administrationen_US
dc.language.isoen_US
dc.publisherAmerican Meteorological Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1175/2009jtecho659.1en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourcePNASen_US
dc.titleMeasurements of Sea Surface Height Variability in the Eastern South Atlantic from Pressure Sensor-Equipped Inverted Echo Sounders: Baroclinic and Barotropicen_US
dc.typeArticleen_US
dc.identifier.citationBaker-Yeboah, Sheekela, D. Randolph Watts, and Deirdre A Byrne. “Measurements of Sea Surface Height Variability in the Eastern South Atlantic from Pressure Sensor–Equipped Inverted Echo Sounders: Baroclinic and Barotropic Components.” Journal of Atmospheric and Oceanic Technology 26.12 (2009) : 2593-2609. c2009 American Meteorological Societyen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciencesen_US
dc.contributor.approverBaker-Yeboah, Sheekela
dc.contributor.mitauthorBaker-Yeboah, Sheekela
dc.relation.journalJournal of Atmospheric and Oceanic Technologyen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsBaker-Yeboah, Sheekela; Watts, D. Randolph; Byrne, Deirdre A.en
mit.licensePUBLISHER_POLICYen_US


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