Paper No. 7
Presentation Time: 3:10 PM
PROXY EVIDENCE FOR THE ROLE OF GLOBAL TELECONNECTIONS IN MIDDLE EAST HYDROCLIMATE VARIABILITY
Observations of 19th and 20th century precipitation in the Dead Sea watershed region display a multidecadal, anti-phase relationship to North Atlantic (NAtl) sea surface temperature (SST) variability, such that when the NAtl is relatively cold, Jerusalem experiences higher than normal precipitation and vice versa. This association is underlined by a significant negative correlation to precipitation in the sub-Saharan Sahel (despite the seasonal differences in rainfall occurrence) and a positive correlation to precipitation in western North America, areas that are also affected by multidecadal NAtl SST variability. These linkages are also consistent with general circulation model experiments and can be explained by the way the atmosphere responds to basin-wide NAtl SST variations. We show that 20th century observations are consistent with broad range of Holocene hydroclimatic fluctuations from the epochal, to the millennial and centennial time scales, as displayed by the Dead Sea and Sahel lake levels and by direct and indirect proxy indicators of NAtl SSTs. On the epochal time scale, the gradual cooling of NAtl SSTs throughout the Holocene in response to precession-driven reduction of summer insolation is associated with previously well-studied wet-to-dry transition in the Sahel and with a general increase in Dead Sea lake levels from low stands after the Younger Dryas to higher stands in the mid- to late-Holocene. On the millennial and centennial time scales there is also evidence for an anti-phase relationship between Holocene variations in the Dead Sea and Sahel lake levels and with proxy indicators of NAtl SSTs.