Fluctuation of the sea surface dynamic topography southeast of Japan as estimated from Seasat altimetry data

Kaoru Ichikawa, Shiro Imawaki

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The sea surface dynamic topography (the sea surface height relative to the geoid; hereafter abbreviated SSDT) can be divided into the temporal mean SSDT and the fluctuation SSDT around the mean. We use the optimal interpolation method to reduce the satellite radial orbit error and estimate the fluctuation SSDT southeast of Japan from Seasat altimetry data during the 17-day near-repeat mission. The fluctuation SSDT is further combined with the mean geopotential anomalies estimated from hydrographic data during the Seasat mission in order to give the approximated total SSDT, called here the composite SSDT (the approximated mean plus fluctuation SSDT's). The fluctuation SSDT is in accord with the low-frequency sea-level fluctuation recorded at tide gauge stations in the Japanese islands. The composite SSDT describes thoroughly variations of the location of the Kuroshio axis south of Japan determined on the basis of the GEK (Geomagnetic Electro-Kinematograph) surface velocities and the horizontal temperature distribution. The composite SSDT also agrees with oceanic variations east of Japan found in the temperature distribution at the depth of 200 m. These results confirm that the SSDT derived from altimetry data can provide fairly precise synoptic views of low-frequency oceanic phenomena.

Original languageEnglish
Pages (from-to)155-177
Number of pages23
JournalJournal of Oceanography
Volume48
Issue number2
DOIs
Publication statusPublished - Jun 1 1992

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Seasat
altimetry
sea surface
topography
sea surface height
tide gauge
geoid
geopotential
interpolation
temperature
sea level
anomaly
distribution

All Science Journal Classification (ASJC) codes

  • Oceanography

Cite this

Fluctuation of the sea surface dynamic topography southeast of Japan as estimated from Seasat altimetry data. / Ichikawa, Kaoru; Imawaki, Shiro.

In: Journal of Oceanography, Vol. 48, No. 2, 01.06.1992, p. 155-177.

Research output: Contribution to journalArticle

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