OBSERVATIONS OF FLOW VARIABILITY IN THE NORTHERN SOUTH CHINA SEA

Abstract:

We deployed five Pressure-recording Inverted Echo Sounders (PIES) along a satellite altimeter track across the continental slope of the northern South China Sea (NSCS) from October 2012 to July 2014, and obtained a time series of volume transport (VT_PIES) across the section from their records. Applying the empirical relationship between VT_PIES and the satellite altimeter sea-surface height anomaly difference across the section, we obtained a time series of volume transport (VT_NSCS) over 22 years from 1992 to 2014. The VT_NSCS shows a small mean value of -1.64 Sv (i.e., toward the southwest) but a significant seasonal reversal and mesoscale eddy induced fluctuations (-11.79-19.73 Sv). The monthly mean of VT_NSCS over 22 years shows a maximum (3.59 Sv) in July and a minimum (-7.26 Sv) in December. This is the first long time series of volume transport for the NSCS based on in situ data.