Temperature correction and usefulness of ocean bottom pressure data from cabled seafloor observatories around Japan for analyses of tsunamis, Ocean tides, and low-frequency geophysical phenomena

Daisuke Inazu, Ryota Hino

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Ocean bottom pressure (OBP) data obtained by cabled seafloor observatories deployed around Japan, are known to be significantly affected by temperature changes. This paper examines the relationship between the OBP and temperature records of six OBP gauges in terms of a regression coefficient and lag at a wide range of frequencies. No significant temperature dependency is recognized in secular variations, while substantial increases, at rates of the order of 1 hPa/year, are commonly evident in the OBP records. Strong temperature dependencies are apparent for periods of hours to days, and we correct the OBP data based on the estimated OBP-temperature relationship. At periods longer than days, the temperature corrections work well for extracting geophysical signals for OBP data at a station off Hokkaido (KPG2), while other corrected data show insufficient signal-to-noise ratios. At a tsunami frequency, the correction can reduce OBP fluctuations, due to rapid temperature changes, by as much as millimeters, and is especially effective for data at a station off Shikoku (MPG2) at which rapid temperature changes most frequently occur. A tidal analysis shows that OBP data at a station off Honshu (TMl), and at KPG2, are useful for studies on the long-term variations of tidal constituents.

Original languageEnglish
Pages (from-to)1133-1149
Number of pages17
Journalearth, planets and space
Volume63
Issue number11
DOIs
Publication statusPublished - 2011

Keywords

  • Ocean bottom pressure
  • Ocean tide
  • Oceanic variation
  • Temperature correction
  • Tsunami

ASJC Scopus subject areas

  • Geology
  • Space and Planetary Science

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