A comparison of sea surface salinity in the equatorial Pacific Ocean during the 1997–1998, 2012–2013, and 2014–2015 ENSO events
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Sea surface salinity (SSS) variability during the 1997–1998 El Niño event and the failed 2012–2013 and 2014–2015 El Niño events is explored using a combination of observations and ocean reanalyses. Previously, studies have mainly focused on the sea surface temperature (SST) and sea surface height (SSH) variability. This analysis utilizes salinity data from Argo and the Simple Ocean Data Assimilation (SODA) reanalysis to examine the SSS variability. Advective processes and evaporation minus precipitation (E−P) variability is understood to influence SSS variability. Using surface wind, surface current, evaporation, and precipitation data, we analyze the causes for the observed SSS variability during each event. Barrier layer thickness and upper level salt content are also examined in connection to subsurface salinity variability. Both advective processes and E-P variability are important during the generation and onset of a successful El Niño, while a lack of one or both of these processes leads to a failed ENSO event.
KeywordsSea surface salinity El Niño Argo SODA reanalysis
This work is partially supported by the NASA Physical Oceanography Program Award #NNX13AM60G awarded to Bulusu Subrahmanyam. The authors would like to thank the following data centers for providing the datasets used to conduct this study: the SODA and Texas A&M University Research Group (http://www.soda.tamu.edu/data.htm), the IPRC APDRC (http://apdrc.soest.hawaii.edu/projects/argo/), ECMWF ERA-Interim (http://apps.ecmwf.int/datasets/data/interim-full-daily/levtype=sfc/), NASA JPL PO.DAAC (https://podaac.jpl.nasa.gov/dataset/OSCAR_L4_OC_third-deg), the Woods Hole Oceanographic Institution OA Flux Project (http://oaflux.whoi.edu/), and NASA Goddard Space Flight Center (http://precip.gsfc.nasa.gov, http://trmm.gsfc.nasa.gov/). The authors would also like to acknowledge the editor and the anonymous reviewers, whose comments contributed significantly to this paper.
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