Florida Current surface temperature and salinity variability during the last millennium
Lund, David C.
Curry, William B.
MetadataShow full item record
The salinity and temperature of the Florida Current are key parameters affecting the transport of heat into the North Atlantic, yet little is known about their variability on centennial time scales. Here we report replicated, high-resolution foraminiferal records of Florida Current surface hydrography for the last millennium from two coring sites, Dry Tortugas and the Great Bahama Bank. The oxygen isotopic composition of Florida Current surface water (δ18Ow) near Dry Tortugas increased 0.4‰ during the course of the Little Ice Age (LIA: ~1200-1850 A. D.), equivalent to a salinity increase of 0.8-1.5 psu. On the Great Bahama Bank, where surface waters are influenced by the North Atlantic subtropical gyre, δ18Ow increased by 0.3‰ during the last 200 years. Although a portion (~0.1‰) of this shift may be an artifact of anthropogenically-driven changes in surface water ΣCO2, the remaining δ18Ow signal implies a 0.4 to 1 psu increase in salinity after 200 yr BP. The simplest explanation of the δ18Ow data is southward migration of the Atlantic Hadley circulation during the LIA. Scaling of the δ18Ow records to salinity using the modern low-latitude δ18Ow-S slope produces an unrealistic reversal in the salinity gradient between the two sites. Only if δ18Ow is scaled to salinity using a high-latitude δ18Ow-S slope can the records be reconciled. Changes in atmospheric 14C paralleled shifts in Dry Tortugas δ18Ow, suggesting that variable solar irradiance paced centennialscale ITCZ migration and changes in Florida Current salinity during the last millennium.
Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography, 21 (2006): PA2009, doi:10.1029/2005PA001218.
Showing items related by title, author, creator and subject.
On sea surface salinity skin effect iInduced by evaporation and implications for remote sensing of ocean salinity Yu, Lisan (American Meteorological Society, 2010-01)The existence of a cool and salty sea surface skin under evaporation was first proposed by Saunders in 1967, but few efforts have since been made to perceive the salt component of the skin layer. With two salinity missions ...
Yu, Lisan (John Wiley & Sons, 2015-06-08)The Intertropical Convergence Zone (ITCZ) is a major source of the surface freshwater input to the tropical open ocean. Under the ITCZ, sea-surface salinity (SSS) fronts that extend zonally across the basins are observed ...
From salty to fresh—salinity processes in the Upper-ocean Regional Study-2 (SPURS-2) : diagnosing the physics of a rainfall-dominated salinity minimum Schmitt, Raymond W.; Asher, William; Bingham, Frederick; Carton, James A.; Centurioni, Luca; Farrar, J. Thomas; Gordon, Arnold L.; Hodges, Benjamin A.; Jessup, Andrew T.; Kessler, William S.; Rainville, Luc; Shcherbina, Andrey Y. (The Oceanography Society, 2015-03)One of the notable features of the global ocean is that the salinity of the North Atlantic is about 1 psu higher than that of the North Pacific. This contrast is thought to be due to one of the large asymmetries in the ...