Annual and decadal-scale hydroclimatic variability is a key characteristic embedded into climate insitu. It is therefore crucial to study hydroclimatic variability in order to understand its effects on climate derivatives such as hydrological processes and water availability. However, the study of this variability from modern records is limited due to their relatively short span, whereas model simulations relaying on modern dynamics could miss some of its aspects. Here we study annual to decadal hydroclimatic variability in the Levant using two sedimentary sections covering ~700 years deposited at ~18 and 27~ Ka retrieved from the depocenter of the Dead Sea, which has been continuously recording environmental conditions throughout the late Pleistocene. We focus on two ~700 years long series of annually-deposited laminated intervals (i.e., varves) representing two episodes of opposing mean climates, deposited during lake level rise and fall at 27 and 18 Ka, respectively. These two series comprise alternations of authigenic aragonite precipitated during summer and flood-derived detrital laminae deposited during winter. Within this record, aragonite laminae serve as a proxy of annual inflow and epilimnion dilution, whereas detrital laminae comprise sub-laminae that record individual floods. The two series depict distinct characteristics with increased mean and variance of annual inflow and flood frequency during "wetter", with respect to the "dryer", conditions. In addition, decades of intense flood frequency are identified (e.g., clusters), suggesting shifts between centennial-scale climatic regimes, which are particularly pronounced during wetter, lake-rising conditions. The combined application of multiple time series analyses indicates that episodes of falling lake levels are characterized by multiple pronounced quasi-periodic components with periodicities of 2-4, 6-8 and ~12 years, whereas the rising lake level episode presents weaker, less-persistent periodical components with similar periodicities. Combining these observations with the modern synoptic-scale hydroclimatology indicates shifts in the dominance of key synoptic systems governing rainfall, annual inflow and flood frequency in the eastern Mediterranean over centennial time-scale. [ABSTRACT FROM AUTHOR]
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