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Dynamics of the South Java Current in the Indo‐Australian Basin
Author(s) -
Sprintall Janet,
Chong Jackson,
Syamsudin Fadli,
Morawitz Werner,
Hautala Susan,
Bray Nan,
Wijffels Susan
Publication year - 1999
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 - 10.1029/1999gl002320
Subject(s) - kelvin wave , geology , upwelling , downwelling , advection , oceanography , current (fluid) , boundary current , monsoon , precipitation , current meter , climatology , ocean current , meteorology , geography , physics , thermodynamics
A year‐long deployment of a mooring in the South Java Current (SJC) of Indonesia provides a fascinating insight into this poorly understood, semi‐annually reversing boundary current. A striking three‐week period of southeastward flow begins in mid‐May 1997. An analytical model directly account for changes in velocity at this time due to the passage of a westerly wind‐forced, downwelling Kelvin wave from the equatorial western Indian Ocean. The entire water column is warmed, with a fresh cap overlying salty water, consistent with the Indian Ocean source. Following the wave passage, the SJC is north‐westward, and the prevailing south‐easterly monsoon winds lead to upwelling of cold, salty water. In early August, the SJC abruptly returns to south‐eastward flow, and remains so until November 1997 in the face of steady south‐easterly local winds. The anomalous flow direction and cooler water are related to an upwelling Kelvin wave, forced by unseasonal prolonged easterly wind anomalies in the equatorial Indian Ocean. After a small reversal of flow in November 1997, the SJC is south‐eastward, as expected during the north‐east monsoon. A trend toward increasing salinities in the record is attributed to the increased input of salty Indian Ocean water, enhanced evaporation, and a lack of freshwater advection due to the regionally reduced precipitation during the 1997‐98 El Niño.