Salinity change in the subtropical Atlantic : secular increase and teleconnections to the North Atlantic Oscillation

• Published in: Geophysical Research Letters
• Main Authors: Rosenheim, Brad E., Swart, Peter K., Thorrold, Simon R., Eisenhauer, Anton, Willenz, Philippe
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2005
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: https://hdl.handle.net/1912/3319

Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 32 (2005): L02603, doi:10.1029/2004GL021499. Recent studies comparing shipboard data between the 1950's and the 1990's have shown significant, heterogeneous adjustments of the temperature-salinity structure of the N. Atlantic Ocean. Here, we present proxy records of temperature and salinity from aragonite sclerosponge skeletons, extending existing records of the Salinity Maximum Waters (SMW) of the N. Atlantic back to 1890. These proxy records show secular temperature increases of 1.6–2.0°C, higher than published global averages, and salinity increases of 0.35–0.5 psu, smaller than short-term secular trends recently measured. Salinity reconstructions vary more significantly on the decadal scale, showing changes that are related to low-frequency variations of the North Atlantic Oscillation (NAO). On both secular and decadal time scales, the records indicate significant thermohaline changes in the SMW, either via forcing at the surface or increasing depths of density surfaces in the Bahamas. This project was supported by National Science Foundation grants 9819147 and 0136941 (to P.K.S) and 9876565 and 0134998 (to S.R.T).