HR: 08:00h
AN: PP41C-01 INVITED     [Abstracts]
TI: Holocene Variability in the Eastern Mediterranean Sea
AU: * Rohling, E J
EM: E.Rohling@noc.soton.ac.uk
AF: National Oceanography Centre, European Way, Southampton, SO14 3ZH United Kingdom
AB: Holocene palaeoceanographic variability in the eastern Mediterranean reflects an intricate mix of fluctuations related to both Atlantic mid-to-high latitude climate systems, and the African monsoon. The Atlantic systems primarily affect the eastern Mediterranean through invasion of cold and dry continental air from the North, causing sea-surface cooling and evaporation, and hence buoyancy loss that facilitates deep ventilation. It also causes cyclogenesis and the resultant (atmospheric) Mediterranean depressions track in a generally eastward direction, fuelling precipitation over the Levant that can reach even the northernmost Red Sea. Today, northerly air flow over the basin occurs especially due to interaction between an intense low over the central/eastern Mediterranean (caused by high sea-water temperatures), and NE-ward extension of the Azores High or westward ridging of the Siberian High towards NW Europe and Scandinavia. I will discuss the nature, timing, and possible mechanisms of centennial-scale northerly coolings in the eastern Mediterranean, as a pervasive feature of Holocene climate variability. This discussion will also include the consequence of African monsoon intensity variations during the early to middle Holocene, which affected the eastern Mediterranean through fluctuations in Nile River run-off. At that time, an intensified monsoon influence reduced surface salinity and thus enhanced water-column stability in the basin to the point that anoxic conditions developed in poorly ventilated deep waters. Throughout this period, episodes of intensified cooling from the north continued to occur, causing intermittent water-column overturn and associated periods of improved deep-water oxygenation.
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4936 Interglacial
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005