Dynamics of the South Java Coastal Current revealed by RAMA observing network

  • The SJCC is the poorest observed eastern boundary current
  • The SJCC is strongly driven by the remote forcing from the equatorial Indian Ocean
  • Remote forcing from the equator is associated with the wind-forced Kelvin waves
Abstract

A series of Acoustic Doppler Current Profiler (ADCP) measurements moored along the equatorial and coastal wave-guide were used to evaluate the dynamics of the South Java Coastal Current (SJCC). 17-month (December 2008 to May 2010) data from the ADCP off South Java give some insights into the dynamics of the SJCC. The data reveal high variability in the upper 100 m depth, where the core of the SJCC is located. In addition, robust intraseasonal variations at period of 70 - 100 days dominate the SJCC variation. Consistent with previous studies, dynamics of the SJCC is strongly driven by the equatorial waves from the Indian Ocean. Due to a failure in ADCP measurement, the equatorial moorings only have a short overlapping period with the South Java mooring, from the boreal fall 2009 until spring 2010. Nevertheless, the data still exhibit coherence variations in which the strong eastward flow during the boreal fall 2009 and the spring 2010 that observed off South Java can be traced back to the equatorial region. Further analysis confirmed the important role of the remote winds from the equatorial Indian Ocean in affecting the SJCC variations through a generation of eastward propagating wind-forced equatorial Kelvin waves. Nevertheless, the contribution of the local wind forcing is not negligible in generating the SJCC variations.

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