Comparisons of sea surface height variability observed by pressure-recording inverted echo sounders and satellite altimetry in the Kuroshio Extension

Jae Hun Park, Randolph R. Watts, Kathleen A. Donohue, Karen L. Tracey

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Satellite-measured along-track and gridded sea surface height (SSH) anomaly products from AVISO are compared with in situ SSH anomaly measurements from an array of 43 pressure-recording inverted echo sounders (PIESs) in the Kuroshio Extension. PIESs measure bottom pressure (P bot) and round-trip acoustic travel time from the sea floor to the sea surface (τ). The P bot and τ measurements are used to estimate, respectively, the mass-loading and steric height variations in SSH anomaly. All comparisons are made after accurate removal of tidal components from all data. Overall good correlations are found between along-track and PIES-derived SSH anomalies with mean correlation coefficient of 0.97. Comparisons between the two measurements reveal that the mass-loading component estimated from P bot is relatively small in this geographical region. It improves regression coefficients about 5 % and decreases mean root-mean-squared (rms) differences from 7.8 to 6.4 cm. The AVISO up-to-date gridded product, which merges all available satellite measurements of Jason-1, Envisat, Geosat Follow-On, and TOPEX/Poseidon interlaced, shows better correlations and smaller rms differences than the AVISO reference gridded product, which merges only Jason-1 and Envisat. Especially, the up-to-date gridded product reveals 6.8 cm rms improvement on average at sites away from Jason-1 ground tracks. Gridded products exhibit low correlation (0.75-0.9) with PIES-derived SSH in a subregion where the SSH fluctuations have relatively high energy at periods shorter than 20 days.

Original languageEnglish
Pages (from-to)401-416
Number of pages16
JournalJournal of Oceanography
Volume68
Issue number3
DOIs
StatePublished - Jun 2012
Externally publishedYes

Keywords

  • Acoustic echo time
  • Kuroshio Extension
  • Ocean bottom pressure
  • Pressure-recording inverted echo sounder (PIES)
  • Satellite altimetry
  • Sea surface height

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