Change in Salinity of Indonesian Upper Water in the Southeastern Indian Ocean during Argo Period

Abstract

The change in salinity of Indonesian Upper Water (IUW) in the Indian Ocean has been examined during 2004–2020 based on the Argo product. Monthly salinity fields reveal a contrast of IUW salinity changes between two time periods (2004–2013 and 2014–2020) in the outflow of Indonesian Throughflow (ITF) in the Indian Ocean. Freshening of IUW has been observed in the Indian Ocean from 2004-2013 on a basin scale. The opposite changes appear from 2014-2020, when IUW shows a general increase in salinity. The present study shows that oceanic-atmospheric processes in the Maritime Continent influence the changes in the IUW salinity in the southeastern Indian Ocean. The salinity changes are connected to the alteration of the freshwater flux in the Maritime Continent. The ITF enhances subsequent salinity transport into the southeastern Indian Ocean. Zonal atmospheric circulation strength in the tropical region is linked to the shift of the large freshwater flux in the Maritime Continent.