New paper shows significant correlation between solar activity and sea surface temperatures

A new paper published in Paleoceanography finds that reconstructed sea surface temperatures off Caper Hatteras are significantly correlated [at a 95% confidence level] with reconstructed solar activity [total solar irradiance or TSI] over a portion of the last 10,000 years and that "both signals are in phase [correlated at a lower confidence level] over the rest of the studied period." The paper also shows reconstructed South Iceland sea surface temperatures were higher than the present throughout the majority of the past 10,000 years.

Reconstructed South Iceland sea surface temperatures (black line in top graph) vs. thousands of years ago along x axis shows temperatures were higher than the present throughout the majority of the past 10,000 years.

Reconstructed temperatures are significantly correlated with reconstructed Total Solar Irradiance  between 9,500 - 7,000 years ago and " both signals are in phase over the rest of the studied period" [from ~7,000 to ~500 years ago]

PALEOCEANOGRAPHY, VOL. 27, PA1205, 14 PP., 2012

doi:10.1029/2011PA002184

High-resolution sea surface reconstructions off Cape Hatteras over the last 10 ka

Key Points

• High resolution SST and SSS reconstruction off Cape Hatteras
• Low salinity anomaly (3.5-5.2 ka): absence of Labrador current influence
• Millenial NAO pattern and solar variability

Caroline Cléroux

Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ/IPSL, Gif-sur-Yvette, France

Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA

Maxime Debret

Laboratoire de Morphodynamique Continentale et Côtière, Département de Géologie, Université de Rouen, UMR CNRS/INSU 6143, Mont-Saint-Aignan, France

Elsa Cortijo

Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ/IPSL, Gif-sur-Yvette, France

Jean-Claude Duplessy

Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ/IPSL, Gif-sur-Yvette, France

Fabien Dewilde

Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ/IPSL, Gif-sur-Yvette, France

John Reijmer

Department of Sedimentology and Marine Geology, FALW, VU University Amsterdam, Amsterdam, Netherlands

Nicolas Massei

Laboratoire de Morphodynamique Continentale et Côtière, Département de Géologie, Université de Rouen, UMR CNRS/INSU 6143, Mont-Saint-Aignan, France

This study presents high-resolution foraminiferal-based sea surface temperature, sea surface salinity and upper water column stratification reconstructions off Cape Hatteras, a region sensitive to atmospheric and thermohaline circulation changes associated with the Gulf Stream. We focus on the last 10,000 years (10 ka) to study the surface hydrology changes under our current climate conditions and discuss the centennial to millennial time scale variability. We observed opposite evolutions between the conditions off Cape Hatteras and those south of Iceland, known today for the North Atlantic Oscillation pattern. We interpret the temperature and salinity changes in both regions as co-variation of activities of the subtropical and subpolar gyres. Around 8.3 ka and 5.2–3.5 ka, positive salinity anomalies are reconstructed off Cape Hatteras. We demonstrate, for the 5.2–3.5 ka period, that the salinity increase was caused by the cessation of the low salinity surface flow coming from the north. A northward displacement of the Gulf Stream, blocking the southbound low-salinity flow, concomitant to a reduced Meridional Overturning Circulation is the most likely scenario. Finally, wavelet transform analysis revealed a 1000-year period pacing the δ¹⁸O signal [temperature proxy] over the early Holocene. This 1000-year frequency band is significantly coherent with the 1000-year frequency band of Total Solar Irradiance (TSI) between 9.5 ka and 7 ka and both signals are in phase over the rest of the studied period.