Late Pleistocene paleo-hydrological reconstruction based on a new lake-level curve of the Dead Sea

The Dead Sea depression features exceptionally well preserved lacustrine sedimentary sequences and fossil lake-level markers that attest to a much more extensive lake with a maximum highstand water level of more than 200 m above the modern Dead Sea. Lake-level reconstructions based on sedimentary sequences places this highstand phase within the interval of 15-29 ka. Regional paleoclimatic records, however, indicate arid conditions during this time. This apparent contradiction has been explained by spatially heterogeneous moisture delivery resulting from a southward shift of the Westerly wind system and a change in the path and intensity of winter storms. A newly established lake level-chronology based on ¹⁴C- and U/Th-dating of fossil stromatolites has provided contrasting results with respect to previous investigations. Accordingly, the paleolake-highstand was of much shorter duration and occurred at least 10 ka earlier than previously suggested. The new lake-level curve agrees with evidence of arid glacial and humid interglacial periods in the Levant.  In this study we compared these different lake-level reconstructions quantitatively, using a distributed hydrological balance model. This model computes evaporation based on an aerodynamic- /mass-transfer approach. Calibration and validation of this model is achieved by using ~30 years of pre-anthropogenic lake-level observations combined with interpolated climate surfaces based on weather-station records. In the paleo-hydrological reconstruction we account for parameter uncertainties using Monte-Carlo simulations. Our preliminary results show a pronounced sensitivity of the lake-level to precipitation, wind speed, and surface roughness.