Planktonic foraminiferal (Globigerinoides ruber) Mg/Ca ratios and SSTs of sediment cores GeoB9501-4 and GeoB9501-5

Multidecadal variations in Atlantic sea surface temperatures (SST) influence the climate of the Northern Hemisphere. However, prior to the instrumental time period, information on multidecadal climate variability becomes limited, and there is a particular scarcity of sufficiently resolved SST recons...

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Bibliographic Details
Main Authors: Kuhnert, Henning, Mulitza, Stefan
Format: Other/Unknown Material
Language:English
Published: PANGAEA 2011
Subjects:
286
Center for Marine Environmental Sciences
GeoB9501-4
GeoB9501-5
Gravity corer (Kiel type)
Integrierte Analyse zwischeneiszeitlicher Klimadynamik
INTERDYNAMIK
M65/1
MARUM
Mauritania Canyon
Meteor (1986)
MUC
MultiCorer
SL
North Atlantic
North Atlantic oscillation
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.773758
https://doi.org/10.1594/PANGAEA.773758
Description
Summary:Multidecadal variations in Atlantic sea surface temperatures (SST) influence the climate of the Northern Hemisphere. However, prior to the instrumental time period, information on multidecadal climate variability becomes limited, and there is a particular scarcity of sufficiently resolved SST reconstructions. Here, we present an eastern tropical North Atlantic reconstruction of SSTs based on foraminiferal (Globigerinoides ruber pink) Mg/Ca ratios that resolves multidecadal variability over the past 1700 years. Spectral power in the multidecadal band (50 to 70 years period) is significant over several time intervals suggesting that the Atlantic Multidecadal Oscillation (AMO) has been influencing local SST. Since our data exhibit high scatter the absence of multidecadal variability in the remaining record does not exclude the possibility that SST variations on this time scale might have been present without being detected in our data. Cooling by ~0.5 °C takes place between about AD 1250 and AD 1500; while this corresponds to the inception of the Little Ice Age (LIA), the end of the LIA is not reflected in our record and SST remains relatively low. This transition to cooler SSTs parallels the previously reconstructed shift in the North Atlantic Oscillation towards a low pre-20th century mean state and possibly reflects common solar forcing.

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