Characteristics of North Pacific water masses in the Bali Sea

Abstract

The Bali Sea is the trajectory of Indonesian Throughflow (ITF)’s water mass which originates from the North Pacific (NP) Ocean before exiting through Lombok Strait. Therefore, the NP water masses have an impact on the characteristics of the water mass in this area. The study aims to describe the stratification and structure of water masses and calculate the contribution of North Pacific Subtropical Water (NPSW) and North Pacific Intermediate Water (NPIW) using Optimum Multiparameter (OMP) analysis. Stratification of the Bali Sea consists of mixed, thermocline, and deep layers. There were found remnants of NPSW and NPIW inside the thermocline layer, deeper than their origin in the NP Ocean. The core layer of NPSW has an S-max value of 34,6 psu at 120-170m depth, while NPIW has an S-min value of 34,3 psu at the deeper layer, 260-280m depth. The NPIW more dominant presence in the Bali Sea with 80% contribution at a depth of 200-215 meters, while NPSW contribution is 70% at a depth of 110-130 meters. NPSW’s contribution decreases from east to west and vice versa the NPIW.