• Indonesian seas;
  • atmospheric forcing;
  • internal tide;
  • mixing;
  • regional model;
  • tidal forcing

[1] A 1/36° high-resolution nested structure ocean model for Indonesian seas that combines atmospheric and tidal forcings (hereafter referred to as IP3-tide) has been developed based on the modified Princeton Ocean Model (POM). Prior to model application, in 2004, we analyzed the IP3-tide by using observational data, derived data, and a global atlas model. A comparison between IP3-tide with 13 tide gauge points and 11 T/P points resulted in 76–92% certainty. Correlation of temperature from scattered depths and points between the model and XBT data reached 97.5% agreement. The modeled velocity successfully captured the low and high frequency variability shown in INSTANT mooring and TAO/TRITON data. Explicit simulation of tidal processes by regional ocean circulation model improved the representation of circulation in the Indonesian seas. At the tidal frequencies, vertical mixing is increased due to the impact of baroclinic tides and horizontal mixing is enhanced by presence of barotropic tidal motion. Enhanced mixing is responsible for eroding the salinity maximum found in the water masses advected from the Pacific Ocean. On the other hand, seasonal variability changes the vertical density structure of water column, which influences the distribution of internal tidal waves. These results demonstrated the importance of explicit tide simulation by regional ocean circulation model for correct presentation of ocean circulation structure and its variability in the Indonesian seas.