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Sea surface salinity variability during the Indian Ocean Dipole and ENSO events in the tropical Indian Ocean

DRS at CSIR-National Institute of Oceanography

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Title Sea surface salinity variability during the Indian Ocean Dipole and ENSO events in the tropical Indian Ocean
 
Creator Grunseich, G.
Subrahmanyam, B.
Murty, V.S.N.
Giese, B.S.
 
Subject surface salinity
variability
el nino phenomena
southern oscillation
 
Description An ocean reanalysis that covers the period from 1871 to 2008 is used to analyze the interannual variability of sea surface salinity (SSS) in the tropical Indian Ocean. The reanalysis SSS and the SSS anomaly patterns during Indian Ocean Dipole (IOD) and El Nino–Southern Oscillation (ENSO) events are compared with patterns from Argo SSS data. The mean seasonal SSS variation is large in the northern Bay of Bengal compared with variations in the Arabian Sea and equatorial Indian Ocean. During a positive IOD event, positive SSS anomalies are found along the Sumatra coast that are due to the combination of wind-driven upwelling of subsurface high-salinity waters, enhanced evaporation, and anomalous surface circulation. The opposite is true, to a lesser extent, during negative IOD events. A dipole mode index for salinity (DMIS) based on SSS data and a new index based on the average of salinity in a region off the coast of Sumatra are introduced to monitor SSS variability during IOD and ENSO events. The impact of concomitant El Nino events on a positive IOD event is large with freshening (a negative SSS anomaly) in the equatorial Indian Ocean and salting (positive SSS anomaly) off the southern Sumatra coast. The (impact of) intense freshening reaches into the southwestern tropical Indian Ocean. The impact of concomitant La Niña with negative IOD is also large with an intense freshening in the southeastern Arabian Sea and salting off the northern Sumatra coast.
 
Date 2011-12-08T10:08:16Z
2011-12-08T10:08:16Z
2011
 
Type Journal Article
 
Identifier Journal of Geophysical Research, vol.116(C11013); 2011; doi:10.1029/2011JC007456
http://drs.nio.org/drs/handle/2264/3974
 
Language en
 
Rights An edited version of this paper was published by AGU. Copyright [2011] AGU. To view the published open abstract, go to http://dx.doi.org/10.1029/2011JC007456
 
Publisher American Geophysical Union