Abstract. Annual and decadal-scale hydroclimatic variability
describes key characteristics that are embedded into climate in situ and is
of prime importance in subtropical regions. The study of
hydroclimatic variability is therefore crucial to understand its
manifestation and implications for climate derivatives such as hydrological
phenomena and water availability. However, the study of this variability
from modern records is limited due to their relatively short span, whereas
model simulations relying on modern dynamics could misrepresent some of its
aspects. Here we study annual to decadal hydroclimatic variability in the
Levant using two sedimentary sections covering ∼ 700 years
each, from the depocenter of the Dead Sea, which has been continuously
recording environmental conditions since the Pleistocene. We focus on two
series of annually deposited laminated intervals (i.e., varves) that
represent two episodes of opposing mean climates, deposited during MIS2
lake-level rise and fall at ∼ 27 and 18 ka,
respectively. These two series comprise alternations of authigenic aragonite
that precipitated during summer and flood-borne detrital laminae deposited
by winter floods. Within this record, aragonite laminae form a proxy of
annual inflow and the extent of epilimnion dilution, whereas detrital
laminae are comprised of sub-laminae deposited by individual flooding
events. The two series depict distinct characteristics with increased mean
and variance of annual inflow and flood frequency during “wetter”, with
respect to the relatively “dryer”, conditions, reflected by opposite
lake-level changes. In addition, decades of intense flood frequency
(clusters) are identified, reflecting the in situ impact of shifting
centennial-scale climate regimes, which are particularly pronounced during
wetter conditions. The combined application of multiple time series analyses
suggests that the studied episodes are characterized by weak and
non-significant cyclical components of sub-decadal frequencies. The
interpretation of these observations using modern synoptic-scale
hydroclimatology suggests that Pleistocene climate changes resulted in
shifts in the dominance of the key synoptic systems that govern rainfall,
annual inflow and flood frequency in the eastern Mediterranean Sea over
centennial timescales.