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A new milestone has been reached with the launch of two dedicated satellite missions to routinely measure the sea surface salinity (SSS) fields from space at global and regional scales. In the present work, a thorough analysis of the first two years of Aquarius SSS data in the South Indian Ocean is performed. This analysis is focused on three questions: How accurate is Aquarius SSS related to in situ data from the fresh Indonesian Throughflow and salty subtropical waters? Can Aquarius give a spatial context for the data measured by the RAMA mooring system? Are westward propagating annual-period signals described in recent model simulations reproduced by Aquarius-derived SSS? We find Aquarius observations to be highly correlated with those of Argo floats, with small disagreements occurring near oceanic fronts. Aquarius gives fresher SSS than in-situ data in the tropical region due to rainfall effects, except in the eastern basin where the freshening seems to be related to sharp localized leakages of very fresh waters from the Indonesian seas that the Aquarius product is not able to properly resolve. Aquarius data is shown to reproduce quite well the annual cycle obtained from RAMA and Argo gridded datasets. The annual cycle in Aquarius is characterized by SSS propagating features with different characteristics west and east of the Ninety East Ridge. These features are strikingly different from sea surface height waves. Our results suggest that SSS annual propagation might be reflecting coupled ocean-atmosphere dynamics and surface-subsurface processes operating over the entire South Indian Ocean.

Item Type:	Refereed Article
Keywords:	ocean salinity, Rossby wave, Kelvin waves, RAMA, Argo, Indonesian Throughflow, subtropical waters
Research Division:	Earth Sciences
Research Group:	Oceanography
Research Field:	Physical oceanography
Objective Division:	Environmental Policy, Climate Change and Natural Hazards
Objective Group:	Understanding climate change
Objective Field:	Climate variability (excl. social impacts)
UTAS Author:	Menezes, VV (Ms Viviane Menezes)
UTAS Author:	Phillips, HE (Associate Professor Helen Phillips)
ID Code:	92343
Year Published:	2014
Funding Support:	Australian Research Council (DP130102088)
Web of Science® Times Cited:	28
Deposited By:	IMAS Research and Education Centre
Deposited On:	2014-06-16
Last Modified:	2017-11-01
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