Importance and origin of halosteric contribution to sea level change in the southeast Indian Ocean during 2005-2013

Steric sea level change has been identified as one of the major contributors to the regional variability of sea level trends observed by satellite altimetry for the past two decades. This contribution varies in space and time. The temperature (thermosteric) contribution to sea level has generally been found to be more important than the salinity (halosteric) effect. Based on sea level measurements from satellite altimetry and temperature and salinity data from Argo floats during 2005-2013, we found that the southeast Indian Ocean experiences a large halosteric contribution to sea level change. The conspicuously large halosteric contribution is associated with a freshening in the upper 300 m. Neither local atmospheric forcing such as Ekman pumping and E - P nor halosteric signal transmitted from the western tropical Pacific can explain this freshening. An enhanced precipitation in the Maritime Continent region and the observed strengthening of the Indonesian throughflow are the likely causes.