Stratification and Stability of Seawater Mass in Sulawesi Sea

Abstract

Sulawesi waters is one of Indonesian Throughflows (ITF) tracks. Water mass shifts causing by the turbulent flows variant are able to form fluid mixing with a very high fluctuation and seawater mass stratification. This research was able to reveal water mass characteristics (temperature, salinity, and density), stratification, source and stability of seawater mass of of Sulawesi Waters. Temperature and potential density data were used to determine stratifying seawater mass layers by using threshold value method through Brunt-Vaisala Frequency to seek seawater mass in the water column. Results of this research exhibit that Sulawesi Waters possesses mixed surface layer thickness is detected in range of 0-100 meters depth with its temperature down range from 29.12 to 24.21 ⁰C and its gradient fluctuation is about 0.01-0.02 ⁰C. The high salinity value is located in thermocline layer (100 – 200 meters depth) which is in ranged of 34.51 to 34.83 psu, and density stratification are in three water layers such as mixed surface, thermocline, and the deeper. This is indicated by density stratification, where the waters own a high-density gradient forming in thermocline layers, while in the near surface and mid-depth layers, the stratification is relatively lower resulting an instability seawater mass.

The high salinity and temperature condition are in the thermocline layer manifests that both layers, surface and thermocline, are seen salinity dilution. Overall profile points out that thermocline layer tends to posesses the highest value about 0(3.2x10^-4 – 1.8x10^-4) cycl/s. The waters have a high instability water column condition is inferred relating to a high seawater current interacting with sea bottom topography and the seawater instability is located in below thermocline layers (200 – 250 meters depth form the surface).