Spreading of Red Sea overflow waters in the Indian Ocean

Lisa Beal, Amy Ffield, Arnold L. Gordon

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

As a result of its remarkably high salinity and despite its small volume input, remnants of Red Sea Water (RSW) have been identified in the Agulhas Current, over 6000 km distant of their source. This provided the motivation to investigate the long-term mean spreading of RSW throughout the Indian Ocean, using a comprehensive set of observations, taken from the National Oceanographic Data Center archives and from the World Ocean Circulation Experiment Hydrographic Program for the Indian Ocean. After emerging from the Gulf of Aden into the Arabian Sea, RSW spreads predominantly southwestward along the African continental slope, as indicated by strongly inclined isohalines across the Arabian Sea. There is some monsoon variability, so that during the winter monsoon there is more RSW present in the Gulf of Aden and an intensification of southward spreading along the western boundary, between 12° and 5° N. Elsewhere the intermediate depth salinity field of the Indian Ocean appears relatively stationary. Between 5° and 10° S, in the region of the South Equatorial Current, isohalines of the RSW layer become quasi-zonal across the width of the Indian Ocean, only dipping southward toward the western boundary west of 50° E. South of here, there is a strong tongue of RSW spreading southward through the Mozambique Channel and into the Agulhas Current. These conclusions concur with previous localized investigations of intermediate water properties. Using a simple mixing model, the percentage of RSW throughout the Indian Ocean was quantified. It was found that the flux of salt into the Gulf of Aden from the Red Sea is similar to that estimated to cross 32° S in the Agulhas Current. This result implies that all the RSW which is mixed into the interior of the Indian Ocean may eventually be exported at the western boundary. Furthermore, it implies that RSW is the dominant component of the salt budget for the intermediate layer and that input from the Indonesian Seas and via diapycnic processes are small.

Original languageEnglish (US)
Article number1999JC900306
Pages (from-to)8549-8564
Number of pages16
JournalJournal of Geophysical Research C: Oceans
Volume105
Issue numberC4
StatePublished - Apr 15 2000
Externally publishedYes

Fingerprint

Red Sea
sea water
Indian Ocean
seawater
Water
Southern Yemen
gulfs
water
Arabian Sea
monsoons
salinity
monsoon
Salts
salt
Mozambique
sea
salts
intermediate water
tongue
continental slope

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography

Cite this

Beal, L., Ffield, A., & Gordon, A. L. (2000). Spreading of Red Sea overflow waters in the Indian Ocean. Journal of Geophysical Research C: Oceans, 105(C4), 8549-8564. [1999JC900306].

Spreading of Red Sea overflow waters in the Indian Ocean. / Beal, Lisa; Ffield, Amy; Gordon, Arnold L.

In: Journal of Geophysical Research C: Oceans, Vol. 105, No. C4, 1999JC900306, 15.04.2000, p. 8549-8564.

Research output: Contribution to journalArticle

Beal, L, Ffield, A & Gordon, AL 2000, 'Spreading of Red Sea overflow waters in the Indian Ocean', Journal of Geophysical Research C: Oceans, vol. 105, no. C4, 1999JC900306, pp. 8549-8564.
Beal L, Ffield A, Gordon AL. Spreading of Red Sea overflow waters in the Indian Ocean. Journal of Geophysical Research C: Oceans. 2000 Apr 15;105(C4):8549-8564. 1999JC900306.
Beal, Lisa ; Ffield, Amy ; Gordon, Arnold L. / Spreading of Red Sea overflow waters in the Indian Ocean. In: Journal of Geophysical Research C: Oceans. 2000 ; Vol. 105, No. C4. pp. 8549-8564.
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