Persistent monsoonal forcing of Mediterranean Outflow Water dynamics during the late Pleistocene
Bahr, A.; Kaboth, S.; Jiménez-Espejo, F; Sierro, F.J.; Voelker, A.; Lourens, H.L.; Roehl, U.; Reichart, G.J.; Escutia, C.; Hernandez-Molina, F.J.; Pross, J.; Friedrich, O. (2015). Persistent monsoonal forcing of Mediterranean Outflow Water dynamics during the late Pleistocene. Geology (Boulder Colo.) 43(11): 951-954. dx.doi.org/10.1130/G37013.1
In: Geology. Geological Society of America: Boulder. ISSN 0091-7613; e-ISSN 1943-2682, more
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| Authors | | Top |
- Bahr, A.
- Kaboth, S.
- Jiménez-Espejo, F
- Sierro, F.J.
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- Voelker, A.
- Lourens, H.L.
- Roehl, U.
- Reichart, G.J., more
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- Escutia, C.
- Hernandez-Molina, F.J.
- Pross, J.
- Friedrich, O.
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| Abstract |
The mode and vigor of the global oceanic circulation critically dependon the salinity of (sub)surface water masses advected to the lociof deep-water formation. Within the Atlantic meridional overturningcirculation (AMOC), an important supplier of high-salinity waters isthe Mediterranean Outflow Water (MOW), discharging into the NorthAtlantic via the Strait of Gibraltar. Despite its importance for the NorthAtlantic salinity budget, the long-term dynamics of MOW productionhave remained poorly understood. Here we present high-resolution recordsof bottom-current velocity from three drill sites within the Gulfof Cádiz that document a persistent low-latitude forcing of MOW flowspeed over the past ~150 k.y. We demonstrate that the African monsoonis the predominant driver of orbital-scale MOW variability via itsinfluence on the freshwater budget of the eastern Mediterranean Sea.Consequently, MOW formation fluctuates in concert with orbital precessionoverprinted by centennial-scale oscillations of high-latitude origin.We further document that Northern Hemisphere summer insolationminima stimulate maximal injection of MOW-derived salt into theNorth Atlantic, likely strengthening the intermediate AMOC branch.The direct coupling of MOW dynamics to low-latitude climate forcingrepresents a hitherto neglected process for propagating (sub)tropicalclimate signals into the high northern latitudes. |
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