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The role of Equatorial Undercurrent in sustaining the Eastern Indian Ocean upwelling
Author(s) -
Chen Gengxin,
Han Weiqing,
Shu Yeqiang,
Li Yuanlong,
Wang Dongxiao,
Xie Qiang
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl069433
Subject(s) - upwelling , downwelling , thermocline , oceanography , indian ocean dipole , geology , water mass , thermohaline circulation , structural basin , climatology , walker circulation , boundary current , ocean current , indian ocean , paleontology
By combining volume transport and salinity analysis from 1958 to 2014, this paper investigates how the transient Equatorial Undercurrent (EUC) sustains the summer‐fall equatorial eastern Indian Ocean (EIO) upwelling. On seasonal time scales, the EIO upwelling is mainly supplied by the salty water from the western basin through a buffering process: The winter‐spring EUC carries the salty water from the western basin eastward, induces downwelling in the EIO, and pushes portion of the salty water below the central thermocline, which subsequently upwells to the central thermocline during summer‐fall and sustains the EIO upwelling. On interannual time scales, enhanced upwelling occurs during positive Indian Ocean Dipole (+IOD) years. The strong summer‐fall EUC associated with the +IOD supplies water for the intensified upwelling. This research provides new knowledge for basin‐scale mass and property exchanges associated with the EIO upwelling, contributing to our understanding of three‐dimensional ocean circulation and climate variability.