The Estimation of Vertical Mixing in Banda Sea Reni Wijayanti- Ivonne M. Radjawane
Graduate Program in Earth Sciences, Faculty of Earth Sciences and Technology, Bandung Institut of Technology, 40132 Bandung, Indonesia
Oceanography Study Program, Faculty of Earth Sciences and Technology, Bandung Institut of Technology, 40132 Bandung, Indonesia
Research Centre for Oceanography, National Research and Innovation Agency, 14430 Jakarta, Indonesia
Abstract
The Banda Sea is a sea with characteristics where it is the meeting place of the water masses from the North and South Pacific. This discovery of fusion of the water masses from both of them indicates that mixing occurred. In addition, many physical phenomena also happen there and affect vertical mixing, such as monsoons, Indonesian throughflow, upwelling, ENSO influence, and others. Vertical mixing is an important factor in determining the fertility of water. This study aims to find out how the characteristics of vertical mixing by estimating the value of vertical diffusivity (Kz) in the Banda Sea. The data used in this study was obtained from the Banda Sea Expedition by the Indonesian Institute of Sciences Ambon during the period of October 21st to 28th, 2013. The data is observation data from CTD instruments containing temperature, salinity, and depth from 20 stations spread across the Banda Sea arranged in 4 transects transversely. From the results of data processing, 8 identified water masses were found: SPIW, AAIW, PEW, ESPW, WSPW, WNPW, ENPW, and AAMW. Using the Thorpe method, the calculation of vertical diffusivity was estimated at 3 different depths, representing the mixlayer, thermoclin zone, and deep layer at each station, with an average vertical diffusivity value of 1.34x10-5 m2s-1. Spatially, it was found that the calculation estimate of vertical diffusivity was greater than that of the surrounding stations and was on the line passed by the Indonesian throughflow.
Keywords: Banda Sea- Vertical Diffusivity (Kz)- Thorpe Method- Water Mass- Indonesian Througflow
