CPClimate of the PastCPClim. Past1814-9332Copernicus PublicationsGöttingen, Germany10.5194/cp-13-249-2017Precipitation changes in the Mediterranean basin during the Holocene from
terrestrial and marine pollen records: a model–data comparisonPeyronOdileodile.peyron@univ-montp2.frCombourieu-NeboutNathaliehttps://orcid.org/0000-0002-3604-5986BrayshawDavidGoringSimonAndrieu-PonelValérieDespratStéphanieFletcherWillGambinBelindaIoakimChryssanthiJoanninSébastienhttps://orcid.org/0000-0001-8345-9252KotthoffUlrichKouliKaterinahttps://orcid.org/0000-0003-1656-1091MontadeVincentProssJörgSadoriLaurahttps://orcid.org/0000-0002-2774-6705MagnyMichelInstitut des Sciences de l'Evolution (ISEM), Université de
Montpellier, FranceUMR 7194 MNHN, Institut de Paléontologie Humaine, Paris, FranceDepartment of Meteorology, University of Reading, Reading, UKDepartment of Geography, University of Wisconsin-Madison, Wisconsin, USAInstitut Méditerranéen de Biodiversité et d'Ecologie marine
et continentale (IMBE), Aix Marseille Université, Aix-en-Provence,
FranceEPHE, PSL Research University, Laboratoire Paléoclimatologie et
Paléoenvironnements Marins, Pessac, FranceUniversity of Bordeaux, EPOC UMR5805, Pessac, FranceGeography, School of Environment, Education and Development, University
of Manchester, Manchester, UKInstitute of Earth Systems, University of Malta, Msida, MaltaInstitute of Geology and Mineral Exploration, Athens, GreeceCenter for Natural History and Institute of Geology, Hamburg
University, Hamburg, GermanyDepartment of Geology and Geoenvironment, National and Kapodistrian
University of Athens, Athens, GreecePaleoenvironmental Dynamics Group, Institute of Earth Sciences,
Heidelberg University, Heidelberg, GermanyDipartimento di Biologia Ambientale, Università di Roma “La
Sapienza”, Rome, ItalyUniversité de Franche-Comté, UMR6249 Chrono-Environnement,
Besançon, FranceOdile Peyron (odile.peyron@univ-montp2.fr)24March201713324926516June201628June201620January201725January2017This work is licensed under a Creative Commons Attribution 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/This article is available from https://cp.copernicus.org/articles/13/249/2017/cp-13-249-2017.htmlThe full text article is available as a PDF file from https://cp.copernicus.org/articles/13/249/2017/cp-13-249-2017.pdf
Climate evolution of the Mediterranean region during the Holocene exhibits
strong spatial and temporal variability, which is notoriously difficult for
models to reproduce. We propose here a new proxy-based climate synthesis synthesis and
its comparison – at a regional (∼ 100 km) level – with a regional
climate model to examine (i) opposing northern and southern precipitation
regimes and (ii) an east-to-west precipitation dipole during the Holocene
across the Mediterranean basin. Using precipitation estimates inferred from
marine and terrestrial pollen archives, we focus on the early to mid-Holocene
(8000 to 6000 cal yr BP) and the late Holocene (4000 to 2000 cal yr BP), to
test these hypotheses on a Mediterranean-wide scale. Special attention was
given to the reconstruction of season-specific climate information, notably
summer and winter precipitation. The reconstructed climatic trends
corroborate the north–south partition of precipitation regimes during the
Holocene. During the early Holocene, relatively wet conditions occurred in
the south–central and eastern Mediterranean regions, while drier conditions
prevailed from 45∘ N northwards. These patterns then reverse during
the late Holocene. With regard to the existence of a west–east precipitation
dipole during the Holocene, our results show that the strength of this dipole
is strongly linked to the reconstructed seasonal parameter; early-Holocene
summers show a clear east–west division, with summer precipitation having
been highest in Greece and the eastern Mediterranean and lowest over
Italy and the western Mediterranean. Summer precipitation in the east
remained above modern values, even during the late-Holocene interval. In
contrast, winter precipitation signals are less spatially coherent during the
early Holocene but low precipitation is evidenced during the late Holocene. A
general drying trend occurred from the early to late Holocene,
particularly in the central and eastern Mediterranean.
For the same time intervals, pollen-inferred precipitation estimates were
compared with model outputs, based on a regional-scale downscaling (HadRM3)
of a set of global climate-model simulations (HadAM3). The high-resolution
detail achieved through the downscaling is intended to enable a better
comparison between site-based paleo-reconstructions and gridded model
data in the complex terrain of the Mediterranean; the model outputs and
pollen-inferred precipitation estimates show some overall correspondence,
though modeled changes are small and at the absolute margins of statistical
significance. There are suggestions that the eastern Mediterranean
experienced wetter summer conditions than present during the early and late
Holocene; the drying trend in winter from the early to the late Holocene also
appears to be simulated. The use of this high-resolution regional climate
model highlights how the inherently patchy nature of climate signals and paleo-records in
the Mediterranean basin may lead to local signals that are much stronger than the
large-scale pattern would suggest. Nevertheless, the east-to-west division in
summer precipitation seems more marked in the pollen reconstruction than in
the model outputs. The footprint of the anomalies (like today, or dry winters
and
wet summers) has some similarities to modern analogue atmospheric circulation
patterns associated with a strong westerly circulation in winter (positive
Arctic Oscillation–North Atlantic Oscillation (AO–NAO)) and a weak westerly circulation in summer associated with
anticyclonic blocking; however, there also remain important differences
between the paleo-simulations and these analogues. The regional climate
model, consistent with other global models, does not suggest an extension of
the African summer monsoon into the Mediterranean. Therefore, the extent to which
summer monsoonal precipitation may have existed in the southern and eastern
Mediterranean during the mid-Holocene remains an outstanding question.
Introduction
The Mediterranean region is particularly sensitive to climate change due to
its position within the confluence of arid northern African (i.e., subtropically
influenced) and temperate and/or humid European (i.e., midlatitudinal) climates
(Lionello, 2012). Palaeoclimatic proxies, including stable isotopes, lipid
biomarkers, palynological data, and lake levels, have shown that the
Mediterranean region experienced climatic conditions that varied spatially
and temporally throughout the Holocene (e.g., Bar-Matthews and Ayalon, 2011;
Luterbacher et al., 2012; Lionello, 2012; Triantaphyllou et al., 2014, 2016;
Mauri et al., 2015; De Santis and Caldara, 2015; Sadori et al., 2016a;
Cheddadi and Khater, 2016) and well before (eg. Sadori et al., 2016b). Clear
spatial climate patterns have been identified from east to west and from
north to south within the basin (e.g., Zanchetta et al., 2007; Magny et al.,
2009b, 2011, 2013; Zhornyak et al., 2011; Sadori et al., 2013; Fletcher et
al., 2013). Lake-level reconstructions from Italy thus suggest contrasting
patterns of paleo-hydrological changes for the central Mediterranean during
the Holocene (Magny et al., 2012, 2013). Specifically, lake-level maxima
occurred south of approximately 40∘ N in the early to mid-Holocene,
while lakes north of 40∘ N recorded minima. This pattern was
reversed at around 4500 cal yr BP (Magny et al., 2013). Quantitative
pollen-based precipitation reconstructions from sites in northern Italy
indicate humid winters and dry summers during the early to mid-Holocene,
whereas southern Italy was characterized by humid winters and summers; the
N–S pattern reverses in the late Holocene, with drier conditions at southern
sites and wet conditions at northern sites (Peyron et al., 2011, 2013). These
findings support a north–south partition for the central Mediterranean with
regards to precipitation, and they also confirm that precipitation seasonality is
a key parameter in the evolution of Mediterranean climates. The pattern of
shifting N–S precipitation regimes has also been identified for the Aegean
Sea (Peyron et al., 2013). Taken together, the evidence from pollen data and
from other proxies covering the Mediterranean region suggest a climate
response that can be linked to a combination of orbital, ice-sheet, and solar
forcings (Magny et al., 2013).
An east–west pattern of climatic change during the Holocene is also
suggested in the Mediterranean region (e.g., Combourieu Nebout et al., 1998;
Geraga et al., 2010; Colmenero-Hildago et al., 2002; Kotthoff et al., 2008;
Dormoy et al., 2009; Finné et al., 2011; Roberts et al., 2011, 2012;
Luterbacher et al., 2012; Guiot and Kaniewski, 2015). An east–west division
during the Holocene is observed from marine and terrestrial pollen records
(Dormoy et al., 2009; Guiot and Kaniewski, 2015), lake-level reconstructions
(Magny et al., 2013), and speleothem isotopes (Roberts et al., 2011).
This study aims to reconstruct and evaluate N–S and E–W precipitation
patterns for the Mediterranean basin over two key periods in the Holocene,
the early Holocene at 8000–6000 cal yr BP, corresponding to the “Holocene
climate optimum”, and the late Holocene at 4000–2000 cal yr BP, corresponding
to a trend towards drier conditions. Precipitation reconstructions are
particularly important for the Mediterranean region given that precipitation
rather than temperature represents the dominant controlling factor on the
Mediterranean environmental system during the early to mid-Holocene (Renssen
et al., 2012). Moreover, the reconstruction of precipitation parameters seems
robust for the Mediterranean area (Combourieu-Nebout et al., 2009; Mauri et
al., 2015; Peyron et al., 2011, 2013; Magny et al., 2013).
Precipitation is estimated for five pollen records from Greece, Italy, and
Malta and for eight marine pollen records along a longitudinal gradient
from the Alboran Sea to the Aegean Sea. Because precipitation seasonality is
a key parameter of change during the Holocene in the Mediterranean (Rohling
et al., 2002; Peyron et al., 2011; Mauri et al., 2015), the quantitative
climate estimates focus on reconstructing changes in summer and winter
precipitation.
Paleoclimate proxy data are essential benchmarks for model intercomparison
and validation (e.g., Morrill et al., 2012; Heiri et al., 2014). This holds
particularly true considering that previous model–data intercomparisons have
revealed substantial difficulties for general circulation models (GCMs) in simulating key aspects of
mid-Holocene climate (Hargreaves et al., 2013) for Europe and notably for
southern Europe (Davis and Brewer, 2009; Mauri et al., 2014). We also aim to
identify and quantify the spatiotemporal climate patterns in the
Mediterranean basin for the two key intervals of the Holocene (8000–6000 and
4000–2000 cal yr BP) based on regional-scale climate model simulations
(Brayshaw et al., 2011a). Finally, we compare our pollen-inferred climate
patterns with regional-scale climate model simulations in order to critically
assess the consistency of the climate reconstructions revealed by these two
complimentary routes.
Locations of terrestrial and marine pollen records along a
longitudinal gradient from west to east and along a latitudinal gradient
from northern Italy to Malta. Ombrothermic diagrams are shown for each site,
calculated with the New LocClim software program and database, which provides
estimates of average climatic conditions at locations for which no
observations are available (marine pollen cores, for example).
The first originality of our approach is that we estimate the magnitude of
precipitation changes and reconstruct climatic trends across the
Mediterranean using both terrestrial and marine high-resolution pollen
records. The reconstructed signal is then more regional than in the studies
based on terrestrial records alone. Moreover, this study aims to reconstruct
precipitation patterns for the Mediterranean basin over two key periods in
the Holocene, while the existing large-scale quantitative paleoclimate
reconstructions for the Holocene are often limited to the mid-Holocene (6000 yr BP; Cheddadi et al., 1997; Bartlein et al., 2011; Mauri et al.,
2014), except for the climate reconstruction for Europe proposed by the study of
Mauri et al. (2015).
The second originality of our approach is that we propose a data–model
comparison based on (1) two time slices instead of just the mid-Holocene, a
standard benchmark time period for this kind of data–model comparison; (2) a
high resolution regional model (RCM), which provides a better representation
of local and regional processes and helps to better simulate the localized patchy impacts of Holocene climate change when compared to coarser
global GCMs (e.g., Mauri et al., 2014); and (3) changes in seasonality,
particularly changes in summer atmospheric circulation that have not been
widely investigated (Brayshaw et al., 2011).
Sites, pollen records, and models
The Mediterranean region is at the confluence of continental and tropical
air masses. Specifically, the central and eastern Mediterranean is
influenced by monsoonal systems, while the northwestern Mediterranean is
under stronger influence from midlatitude climate regimes (Lionello et al.,
2006). Mediterranean winter climates are strongly affected by storm systems
originating over the Atlantic. In the western Mediterranean, precipitation
is predominantly affected by the North Atlantic Oscillation (NAO), while
several systems interact to control precipitation over the northern and
eastern Mediterranean (Giorgi and Lionello, 2008). Mediterranean summer
climates are dominated by descending high-pressure systems that lead to
dry and hot conditions, particularly over the southern Mediterranean where
climate variability is strongly influenced by African and Asian monsoons
(Alpert et al., 2006), with strong geopotential blocking anomalies over
central Europe (Giorgi and Lionello, 2008; Trigo et al., 2006).
The palynological component of our study combines results from five
terrestrial and eight marine pollen records to provide broad coverage of the
Mediterranean basin (Fig. 1, Table 1). The terrestrial sequences comprise
pollen records from lakes along a latitudinal gradient from northern Italy
(Ledro and Accesa lakes) to Sicily (Lake Pergusa), one pollen record from
Malta (Burmarrad), and one pollen record from Greece (Tenaghi Philippon). The
marine pollen sequences are situated along a longitudinal gradient across the
Mediterranean Sea: from the Alboran Sea (ODP Site 976 and core MD95-2043),
Siculo–Tunisian strait (core MD04-2797), Adriatic Sea (core MD90-917), and
Aegean Sea (cores SL152, MNB-3, NS14, HCM2/22). For each record we used the
chronologies as reported in the original publications (see Table 1 for
references).
Metadata for the terrestrial and marine pollen records evaluated.
The temporal resolution is calculated for the two periods (8000–6000 and
4000–2000) and for the entire record.
Terrestrial pollen records LongitudeLatitudeElev.TemporalReferences(m a.s.l)resolution(non-exhaustive)Ledro(Northern Italy)10∘76′ E45∘87′ N6528000–6000: 71 4000–2000: 60 10966-10: 66Joannin et al. (2013),Magny et al. (2009, 2012a),Vannière et al. (2013),Peyron et al. (2013)Accesa(Central Italy)10∘53′ E42∘59′ N1578000–6000: 90 4000–2000 : 133 11029-100: 97Drescher-Schneider et al. (2007), Magny et al. (2007, 2013),Colombaroli et al. (2008),Sadori et al. (2011),Vannière et al. (2011),Peyron et al. (2011, 2013)Trifoglietti(Southern Italy)16∘01′ E39∘33′ N10488000–6000: 95 4000–2000: 86 9967-14: 73Joannin et al. (2012),Peyron et al. (2013)Pergusa(Sicily)14∘18′ E37∘31′ N6678000–6000: 166 4000–2000: 90 12749-53: 154Sadori and Narcisi (2001),Sadori et al. (2008, 2011, 2013, 2016b),Magny et al. (2011, 2013)TenaghiPhilippon(Greece)24∘13.4′ E40∘58.4′ N408000–6000: 64 4000–2000: no 10369-6371:53Pross et al. (2009, 2015),Peyron et al. (2011), Schemmel et al. (2016)Burmarrad(Malta)14∘25′ E35∘56′ N0.58000–6000: 400 4000–2000: 285 6904-1730: 110Djamali et al. (2013),Gambin et al. (2016)Marine pollen records LongitudeLatitudeWaterTemporalReferencesdepthresolutionODP 976(Alboran Sea)4∘18′ W36∘12′ N11088000–6000: 142 4000–2000: 181 10903-132: 129Combourieu-Nebout et al. (1999, 2002, 2009), Dormoy et al., (2009)MD95-2043(Alboran Sea)2∘37′ W36∘9′ N18418000–6000: 111 4000–2000: 142 10952-1279: 106Fletcher and Sánchez Goñi (2008),Fletcher et al. (2010)MD90-917(Adriatic Sea)17∘37′ E41∘97′ N8458000–6000: 90 4000–2000: 333 10495-2641: 122Combourieu-Nebout et al. (2013)MD04-2797(Siculo–Tunisian strait)11∘40′ E36∘57′ N7718000–6000: 111 4000–2000: 666 10985-2215: 127Desprat et al. (2013)SL152(Northern Aegean Sea)24∘36′ E40∘19′ N9788000–6000: 60 4000–2000: 95 9999-0: 76Kotthoff et al. (2008, 2011),Dormoy et al. (2009)NS14(Southern Aegean Sea)27∘02′ E36∘38′ N5058000–6000: 80 4000–2000: 333 9988-2570: 107Kouli et al. (2012), Gogou et al. (2007), Triantaphyllou et al. (2009a, b)HCM2/22(Southern Crete)24∘53′ E34∘34′ N22118000–6000: 181 4000–2000: 333 8091-2390: 247Ioakim et al. (2009), Kouli et al. (2012), Triantaphyllou et al. (2014)MNB-3(Northern Aegean Sea)25∘00′ E39∘15′ N8008000–6000: 153 4000–2000: 166 8209-2273: 138Geraga et al. (2010), Kouli et al. (2012), Triantaphyllou et al. (2014)
Climate reconstructions for summer and winter precipitation (Figs. 2 and 3),
inferred from the terrestrial sequences and marine pollen records, were
performed for two key intervals of the Holocene: 8000–6000 and
4000–2000 cal yr BP; the climate values available during each period have
been averaged. We use here the modern analogue technique (MAT; Guiot, 1990),
a method that compares fossil pollen assemblages to modern pollen
assemblages with known climate parameters. The MAT is calibrated using an
expanded surface pollen dataset with more than 3600 surface pollen samples
from various European ecosystems (Peyron et al., 2013). In this dataset, 2200
samples are from the Mediterranean region, and the results show that the
analogues selected here are limited to the Mediterranean basin. Since the MAT
uses the distance structure of the data and essentially performs local
fitting of the climate parameter (as the mean of n closest sites),
it may be less susceptible to increased noise in the dataset and less
likely to report spurious values than others methods (for more details on the
method, see Peyron et al., 2011). Pinus is overrepresented in marine
pollen samples (Heusser and Balsam, 1977; Naughton et al., 2007), and as such
Pinus pollen was removed from the assemblages (both modern and
fossil) for the calibration of marine records using MAT. The reliability of
quantitative climate reconstructions from marine pollen records has been
tested using marine core-top samples from the Mediterranean in
Combourieu-Nebout et al. (2009), which shows an adequate consistency between
the present day observed and MAT estimations for annual and summer
precipitation values; however, the MAT seems to overestimate the winter
precipitation reconstructions in comparison with the observed values. More
top cores are needed to validate these results at the scale of the
Mediterranean basin, particularly in the eastern part where only one marine
top core was available (Combourieu-Nebout et al., 2009).
The climate model simulations used in the model–data comparison are taken
from Brayshaw et al. (2010, 2011a, b). The HadAM3 global atmospheric model
(resolution 2.5∘ latitude × 3.75∘ longitude, 19 vertical levels; Pope et al., 2000) is coupled to a slab ocean (HadSM3,
Hewitt et al., 2001) and used to perform a series of time slice experiments.
Each time slice simulation corresponds to 20 model years after spin-up (40
model years for preindustrial). The time slices correspond to
present day (1960–1990), 2000, 4000, 6000, and
8000 cal BP conditions and are forced with appropriate insolation
(associated with changes in the Earth's orbit) and atmospheric CO2 and
CH4 concentrations. The heat fluxes in the ocean are held fixed using
values taken from a preindustrial control run (i.e., the ocean
circulation
is assumed to be invariant over the time slices) and there is no sea-level
change, but sea-surface temperatures are allowed to evolve freely. The coarse
global output from the model for each time slice is downscaled over the
Mediterranean region using HadRM3 (i.e., a limited-area version of the same
atmospheric model; resolution 0.44∘× 0.44∘, with
19 vertical levels). Unlike the global model, HadRM3 is not coupled to an
ocean model; instead, sea-surface temperatures are derived directly from the
HadSM3 output.
Following Brayshaw et al. (2011a), time slice experiments are grouped into
mid-Holocene (8000–6000 cal yr BP) and late Holocene
(4000–2000 cal yr BP) experiments because (1) these two periods
are sufficiently distant in the past to be substantially different from the
present but close enough that the model boundary conditions are well known
and
(2) these two periods are rich in high-resolution and well-dated
paleoecological sequences, providing a good spatial coverage suitable for
large-scale model–data comparison. The combination of the simulations into
two experiments (mid- and late Holocene) rather than assessing the two
extreme time slices (2000 and 8000 cal yr BP) is intended to increase the
signal-to-noise ratio by doubling the number of data in each experiment.
This is necessary and possible since the change in forcing between adjacent
time slices is relatively small, making it difficult to detect differences
between each individual simulation. To aid comparison with proxies, changes
in climate are expressed as differences with respect to the present day
(roughly 1960–1990) rather than the preindustrial control run. Therefore,
the climate anomalies shown include a component that is attributable to
anthropogenic increases in greenhouse gases in the industrial period, as well
as longer-term natural changes (e.g., orbital forcing). We suggest it may
be better to use present day to be in closer agreement with the pollen
data (modern samples), which use the late 20th century long-term averages
(1961–1990). However, there are some quite substantial differences between
model runs under present-day and preindustrial forcings (Fig. 4).
Statistical significance is assessed with the Wilcoxon–Mann–Whitney
significance test (Wilks, 1995).
The details of the climate model simulations are discussed at length in
Brayshaw et al. (2010, 2011a, b). These include a detailed discussion of
verification under the present climate, the model's physical and/or dynamical climate
responses to Holocene period forcings, and comparison to other
palaeoclimate modeling approaches (e.g., PMIP projects) and paleoclimate
syntheses. The GCM used (HadAM3 with a slab ocean) is comparable to the
climate models in PMIP2, but key advantages of the present dataset are
(a) the inclusion of multiple time slices across the Holocene period and
(b) that the additional high-resolution regional climate model downscaling enables
the impact of local climatic effects within larger-scale patterns of change
to be distinguished (e.g., the impact of complex topography or coastlines;
Brayshaw et al., 2011a), potentially allowing clearer comparisons between
site-based proxy data and model output.
Results and discussionA north–south precipitation pattern?
Pollen evidence shows contrasting patterns of paleo-hydrological changes in
the central Mediterranean. The early to mid-Holocene was characterized by
precipitation maxima south of around 40∘ N, while at the same time,
northern Italy experienced precipitation minima; this pattern reverses after
4500 cal yr BP (Magny et al., 2012b; Peyron et al., 2013). Other proxies
suggest contrasting north–south hydrological patterns not only in the central
Mediterranean but also across the Mediterranean (Magny et al., 2013),
suggesting a more regional climate signal. We focus here on two time periods
(early to mid-Holocene and late Holocene) in order to test this hypothesis
across the Mediterranean and to compare the results with regional climate
simulations for the same time periods.
Early to mid-Holocene (8000 to 6000 cal yr BP)
Climatic patterns reconstructed from both marine and terrestrial pollen
records seem to corroborate the hypothesis of a north–south division in
precipitation regimes during the Holocene (Fig. 2a). Our results confirm that
northern Italy was characterized by drier conditions (relative to modern),
while the south–central Mediterranean experienced more annual, winter, and
summer precipitation during the early to mid-Holocene (Fig. 2a). Only
Burmarrad (Malta) shows drier conditions in the early to mid-Holocene
(Fig. 2a), although summer precipitation reconstructions are marginally
higher than modern precipitation levels at the site. Wetter summer conditions in the Aegean Sea
suggest a wetter regional climate signal over the central and eastern
Mediterranean. Winter precipitation in the Aegean Sea is less spatially
coherent than summer signal, with dry conditions in the northern Aegean Sea
and/or near-modern conditions in the southern Aegean Sea (Figs. 2a and 3).
Pollen-inferred climate estimates as performed with the modern
analogues technique (MAT): annual precipitation, winter precipitation
(winter is the sum of December, January, and February precipitation), and summer
precipitation (summer is the sum of June, July, and August precipitation).
Changes in climate are expressed as differences with respect to the modern
values (anomalies, mm day-1). The modern values are derived from the
ombrothermic diagrams (see Fig. 1). Two key intervals of the Holocene
corresponding to the two time slice experiments (Fig. 3) have been chosen:
8000–6000 (a) and 4000–2000
(b) cal yr BP. The climate values available during these periods
have been averaged (stars).
Data–model comparison for mid- and late-Holocene precipitation,
expressed in anomaly compared to the present day (mm day-1). Simulations are based
on a regional model (Brayshaw et al., 2010): standard model HadAM3 coupled
to HadSM3 (dynamical model) and HadRM3 (high-resolution regional model). The
hatching representing statistical significance refers to the anomalies shown
on the same plot, i.e., the difference between the experiment (either
8000–6000 or 4000–2000) and the present-day control run. The hatched areas
indicate areas where the changes are not significant (significance level of
0.30). Pollen-inferred climate estimates (stars) are the same as in Fig. 2:
annual precipitation, winter precipitation (winter is the sum of December,
January, and February precipitation), and summer precipitation (summer is the sum
of June, July, and August precipitation).
Non-pollen proxies, including marine and terrestrial biomarkers (terrestrial
n alkanes), indicate humid mid-Holocene conditions in the Aegean Sea
(Triantaphyllou et al., 2014, 2016). Results within the Aegean support the
pollen-based reconstructions, but non-pollen proxy data are still lacking at
the basin scale in the Mediterranean, limiting our ability to undertake
independent evaluation of precipitation reconstructions.
Very few large-scale climate reconstruction of precipitation exist for the
whole Holocene (Guiot and Kaniewski, 2015; Tarroso et al., 2016) and, even at
local scales, pollen-inferred reconstructions of seasonal precipitation are
very rare (e.g., Peyron et al., 2011, 2013; Combourieu-Nebout et al., 2013;
Nourelbait et al., 2016). Several large-scale studies focused on the
6000 cal yr BP period (Cheddadi et al., 1997; Wu et al., 2007; Bartlein
et al., 2011; Mauri et al., 2014). Wu et al. (2007) reconstructed regional
seasonal and annual precipitation and suggested that precipitation did not
differ significantly from modern conditions across the Mediterranean; however,
scaling issues render it difficult to compare their results with the
reconstructions presented here. Cheddadi et al. (1997) reconstruct
wetter-than-modern conditions at 6000 cal yr BP in southern Europe;
however, their study uses only one record from Italy and measures the
moisture availability index, which is not directly comparable to
precipitation sensu stricto since it integrates temperature and
precipitation. At 6000 cal yr BP, Bartlein et al. (2011) reconstruct
Mediterranean precipitation at values between 100 and 500 mm higher than
modern. Mauri et al. (2015), in an updated version of Davis et al. (2003),
provide a quantitative climate reconstruction comparable to the seasonal
precipitation reconstructions presented here. Compared to Davis et
al. (2003), which focused on reconstruction of temperatures, Mauri et al. (2015) reconstructed seasonal precipitation for Europe and analyzed their
evolution throughout the Holocene. The results from Mauri et al. (2015) differ from
the current study in using MAT with plant functional type scores and in
producing gridded climate maps. Mauri et al. (2015) show wet summers in
southern Europe (Greece and Italy), with a precipitation maximum between 8000
and 6000 cal yr BP, where precipitation was ∼ 20 mm month-1 higher
than modern. As in our reconstruction, precipitation changes in the winter
were small and not significantly different from present-day conditions. Our
reconstructions are in agreement with Mauri et al. (2015), with summer conditions above 45∘ N similar to
present day during the early Holocene
and summer conditions over much of the south–central
Mediterranean south of 45∘ N wetter than today, while winter conditions appear to be
similar to modern values. The results from Mauri et al. (2015) inferred from
terrestrial pollen records and the climatic trends reconstructed here from
marine and terrestrial pollen records seem to corroborate the hypothesis of a
north–south division in precipitation regimes during the early to
mid-Holocene in the central Mediterranean. However, higher resolution above
45∘ N is still needed to validate this hypothesis.
Late Holocene (4000 to 2000 cal yr BP)
Late-Holocene reconstructions of winter and summer precipitation indicate
that the pattern established during the early Holocene was reversed by
4000 cal yr BP, with
precipitation in southern Italy, Malta, and Siculo–Tunisian strait that was similar to present day or lower than present day (Figs. 2b
and 3). Annual precipitation reconstructions suggest drying relative to the
early Holocene, with modern conditions in northern Italy and modern
conditions or drier than modern conditions in central and southern Italy
during most of the late Holocene. Reconstructions for the Aegean Sea still
indicate summer and annual precipitation that was higher than modern values (Fig. 2b). Winter
conditions reverse the early-to-mid-Holocene trend, with modern conditions in
the northern Aegean Sea and wetter-than-modern conditions in the southern
Aegean Sea (Fig. 3). Our reconstructions from all sites show a good fit with
Mauri et al. (2015), except for the Alboran Sea, where we reconstruct
relatively high annual precipitations. Conversely, Mauri et al. (2015)
reconstruct dry conditions, but here too, more sites are needed to confirm or
refute this pattern in Spain. Our reconstruction of summer precipitation for
the eastern Mediterranean is very similar to Mauri et al. (2015), where wet
conditions are reported for Greece and the Aegean Sea.
Model simulation showing present day minus preindustrial
precipitation anomalies (hatching at 70 % statistical significance over
the insignificant regions).
An east–west precipitation pattern?
A precipitation gradient, or an east–west division during the Holocene, has
been suggested for the Mediterranean from pollen data and lake isotopes
(e.g., Dormoy et al., 2009; Roberts et al., 2011; Guiot and Kaniewski, 2015).
However, lake levels and other hydrological proxies around the Mediterranean
basin do not clearly support this hypothesis and rather show contrasting
hydrological patterns south and north of 40∘ N, particularly during
the Holocene climatic optimum (Magny et al., 2013).
Early to mid-Holocene (8000 to 6000 cal yr BP)
The pollen-inferred annual precipitation indicates conditions south of 42∘ N that are unambiguously wetter than
today in the western, central, and eastern
Mediterranean, except for Malta (Fig. 3). A prominent feature of the summer
precipitation signal is an east–west dipole, with increasing precipitation in
the eastern Mediterranean (as for annual precipitation). In contrast, winter
conditions show less spatial coherence, although the western basin, Sicily,
and the Siculo–Tunisian strait appear to have experienced higher
precipitation than present day, while drier conditions exist in the east and in
northern Italy (Fig. 2a).
Our reconstruction shows a good match to Guiot and Kaniewski (2015), who
also discussed a possible east-to-west division in the Mediterranean with
regard to precipitation (summer and annual) during the Holocene. They
reported
wet centennial-scale spells in the eastern Mediterranean during the early
Holocene (until 6000 yr BP), with dry spells in the western Mediterranean.
Mid-Holocene reconstructions show continued wet conditions, with drying
through the late Holocene (Guiot and Kaniewski, 2015). This pattern indicates
a see-saw effect over the last 10 000 years, particularly during dry
episodes in the Near and Middle East. Similar to our findings, Mauri et
al. (2015) also reconstructed high annual precipitation values over much of the
southern Mediterranean and a weak winter precipitation signal. Mauri et
al. (2015) confirm an east–west dipole for summer precipitation, with
conditions drier or close to present in southwestern Europe and wetter in
the central and eastern Mediterranean (Fig. 2b). These studies corroborate
the hypothesis of an east-to-west division in precipitation during the early
to mid-Holocene in the Mediterranean as proposed by Roberts et al. (2011).
Roberts et al. (2011) suggested that the eastern Mediterranean (mainly Turkey and
more eastern regions) experienced higher winter precipitation during the
early Holocene, followed by an oscillatory decline after 6000 yr BP. Our
findings reveal wetter annual and summer conditions in the eastern
Mediterranean, although the winter precipitation signal is less clear.
However, the highest precipitation values reported by Roberts et al. (2011)
were from sites located in western–central Turkey; these sites are absent in
the current study. Climate variability in the eastern Mediterranean during
the last 6000 years is also documented in a number of studies based on
multiple proxies (Finné et al., 2011). Most palaeoclimate proxies
indicate wet mid-Holocene conditions (Bar-Matthews et al., 2003; Stevens et
al., 2006; Eastwood et al., 2007; Kuhnt et al., 2008; Verheyden et al.,
2008),
which agrees well with our results; however, most of these proxies are not
seasonally resolved.
Roberts et al. (2011) and Guiot and Kaniewski (2015) suggest that changes in
precipitation in the western Mediterranean were smaller in magnitude during
the early Holocene, while the largest increases occurred during the
mid-Holocene, around 6000–3000 cal BP, before declining to modern values.
Speleothems from southern Iberia suggest a humid early Holocene
(9000–7300 cal BP) in southern Iberia, with equitable rainfall throughout
the year (Walczak et al., 2015), whereas our reconstructions for the Alboran
Sea clearly show an amplified precipitation seasonality (with higher
annual–winter rainfall and summer rainfall that is similar to present day) for the Alboran sites.
It is likely that seasonal patterns defining the Mediterranean climate must
have been even stronger than present in the early Holocene to support the wider
development of sclerophyll forests in southern Spain (Fletcher et
al., 2013).
Late Holocene (4000 to 2000 cal yr BP)
Annual precipitation reconstructions suggest drier or near-modern conditions
in central Italy, the Adriatic Sea, the Siculo–Tunisian strait, and Malta (Figs. 2b
and 3). In contrast, the Alboran and Aegean seas remain wetter. Winter and
summer precipitation produce opposing patterns; a clear east–west division
still exists for summer precipitation, with a maximum in the eastern and a
minimum over the western and central Mediterranean (Fig. 2b). Winter
precipitation shows the opposite trend, with a minimum in the central
Mediterranean (Sicily, Siculo–Tunisian strait, and Malta) and eastern
Mediterranean and a maximum in the western Mediterranean (Figs. 2b and 3).
Our results are also in agreement with lakes and speleothem isotope records
over the Mediterranean for the late Holocene (Roberts et al., 2011) and the
Finné et al. (2011) palaeoclimate synthesis for the eastern
Mediterranean. There is a good overall correspondence between trends and
patterns in our reconstruction and that of Mauri et al. (2015), except for
the Alboran Sea. High-resolution speleothem data from southern Iberia show
Mediterranean climate conditions in southern Iberia between 4800 and
3000 cal BP (Walczak et al., 2015) that are in agreement with our
reconstruction. The Mediterranean climate conditions reconstructed here for
the Alboran Sea during the late Holocene are consistent with a climate
reconstruction available from the Middle Atlas (Morocco), which shows a trend
over the last 6000 years towards arid conditions as well as higher
precipitation seasonality between 4000 and 2000 cal yr BP (Nourelbait et
al., 2016). There is also good evidence from many records to support late-Holocene aridification in southern Iberia. Paleoclimatic studies document a
progressive aridification trend since ∼ 7000 cal yr BP (e.g., Carrion
et al., 2010; Jimenez-Moreno et al., 2015; Ramos-Roman et al., 2016),
although a reconstruction of the annual precipitation inferred from pollen
data with the probability density function method indicates stable and dry
conditions in south of the Iberian Peninsula between 9000 and
3000 cal BP (Tarroso et al., 2016).
The current study shows that a prominent feature of late-Holocene climate is
the east–west division in summer precipitation: summers were overall dry or
near-modern in the central and western Mediterranean and clearly wetter in
the eastern Mediterranean. In contrast, winters were drier or near modern levels in
the central and eastern Mediterranean (Fig. 3), while they were only wetter
in the Alboran Sea.
Data–model comparison
Figure 3 shows the data–model comparisons for the early to mid-Holocene
(a) and late Holocene (b) compared to the present-day control run (in
anomalies, with statistical significance hatched). Encouragingly, there is a
good overall correspondence between patterns and trends in pollen-inferred
precipitation and model outputs. Caution is required when interpreting
climate model results, however, as many of the changes depicted in Fig. 3 are
very small and of marginal statistical significance, suggesting a high degree
of uncertainty around their robustness.
For the early to mid-Holocene, both the model and data indicate wet annual and
summer conditions in Greece and in the eastern Mediterranean and conditions that were drier than
today in northern Italy. There are indications of an east-to-west
division in summer precipitation simulated by the climate model (e.g.,
between the ocean to the south of Italy and over Greece and Turkey), although the
changes are extremely small (not significant with a p<0.30).
Furthermore, in the Aegean Sea, the model shows a good match with
pollen-based reconstructions, suggesting that the increased spatial
resolution of the regional climate model may help to simulate the localized,
patchy, impacts of Holocene climate change when compared to coarser
global GCMs (Fig. 3). In Italy, the model shows a good match with
pollen-based reconstructions with regards to the contrasting north–south
precipitation regimes, but there is little agreement between model output and
climate reconstruction with regard to winter and annual precipitation in
southern Italy. The climate model suggests wetter winter and annual
conditions in the far western Mediterranean (i.e., France, western Iberia, and
the northwestern coast of Africa) – similar to pollen-based reconstructions – and
near-modern summer conditions during summers (except for in France and northern
Africa). A prominent feature of winter precipitation simulated by the model
and partly supported by the pollen estimates is the reduced early-Holocene
precipitation everywhere in the Mediterranean basin except for in the southeast.
Model and pollen-based reconstructions for the late Holocene indicate
declining winter precipitation in the eastern Mediterranean and southern
Italy (Sicily and Malta) relative to the early Holocene. In contrast, late-Holocene summer precipitation is higher than today in Greece and the
eastern Mediterranean, near modern levels in the central and western
Mediterranean, and relatively lower than today in southern Spain and northern
Africa. The east–west division in summer precipitation is strongest during
the late Holocene in the proxy data and there are suggestions that it
appears to be consistently simulated in the climate model; the signal is
reasonably clear in the eastern Mediterranean (Greece and Turkey) but
non-significant in the central and western Mediterranean (Fig. 3).
Our findings can be compared with previous data–model comparisons based on
the same set of climate model experiments; although here we take our
reference period as present day (1960–1990) rather than preindustrial
and thus include an additional signal from recent anthropogenic
greenhouse gas emissions. Previous comparisons nevertheless suggested that
the winter precipitation signal was strongest in the northeastern
Mediterranean (near Turkey) during the early Holocene and that there was a
drying trend in the Mediterranean from the early Holocene to the late
Holocene, particularly in the east (Brayshaw et al., 2011a; Roberts et al.,
2011). This is coupled with a gradually weakening seasonal cycle of surface
air temperatures towards the present.
It is clear that most global climate models (PMIP2, PMIP3) simulate only very
small changes in summer precipitation in the Mediterranean during the
Holocene (Braconnot et al., 2007a, b, 2012; Mauri et al., 2014). The lack of
a summer precipitation signal is consistent with the failure of the
northeastern extension of the west African monsoon to reach the southeastern
Mediterranean, even in the early to mid-Holocene (Brayshaw et al., 2011a).
The regional climate model simulates a small change in precipitation compared
to the proxy results, and it can be robustly identified as statistically
significant. This is to some extent unsurprising, insofar as the regional
climate simulations presented here are themselves driven by data derived
from a coarse global model (which, like its PMIP2/3 peers, does not simulate
an extension of the African monsoon into the Mediterranean during this time
period). Therefore, questions remain about summer precipitation in the
eastern Mediterranean during the Holocene. The underlying climate dynamics
therefore need to be better understood in order to confidently reconcile
proxy data (which suggest increased summer precipitation during the early
Holocene in the eastern Mediterranean) with climate model results (Mauri et
al., 2014). Based on the high-resolution coupled climate model EC-Earth,
Bosmans et al. (2015) show how the seasonality of Mediterranean precipitation
should vary from minimum to maximum precession, indicating a reduction in
precipitation seasonality due to changes in storm tracks and local
cyclogenesis (i.e., no direct monsoon required). Such high-resolution climate
modeling studies (both global and regional) may prove to be key in
simulating the relevant atmospheric processes (both local and remote) and
providing fine-grain spatial detail necessary for comparing results to
paleo-proxy observations.
Another explanation proposed by Mauri et al. (2014) is linked to the changes
in atmospheric circulation. Our reconstructed climate, characterized by dry
winters and wet summers, shows a spatial pattern that is somewhat consistent
with modern day variability in atmospheric circulation rather than simple
direct radiative forcing by insolation. In particular, the gross NW–SE dipole
of reconstructed winter precipitation anomalies is perhaps similar to that
associated with a modern-day positive AO–NAO.
The west coast of Spain is, however, also wetter in our early-Holocene simulations, which would seem to somewhat confound this simple
picture of a shift to a positive NAO-like state compared to present. In summer, an
anticyclonic blocking close to Scandinavia may have caused a more meridional
circulation, which brought dry conditions to northern Europe but relatively
cooler and somewhat wetter conditions to many parts of southern Europe. It is
of note that some climate models that have been used for studying
palaeoclimate have difficulty reproducing this aspect of modern climate
(Mauri et al., 2014). Future work based on transient Holocene model
simulations is important; nevertheless, transient-model simulations have
also shown mid-Holocene data–model discrepancies (Fischer and Jungclaus,
2011; Renssen et al., 2012). It is, however, suggested that further work is
required to fully understand changes in winter and summer circulation
patterns over the Mediterranean (Bosmans et al., 2015).
Data limitations
Classic ecological works for the Mediterranean (e.g., Ozenda, 1975) highlight
how precipitation limits vegetation type in plains and lowland areas, but
temperature gradients take primary importance in mountain systems. Also,
temperature and precipitation changes are not independent but interact
through bioclimatic moisture availability and growing season length (Prentice
et al., 1996). This may be one reason why certain sites may diverge from
model outputs; the Alboran sites, for example, integrate pollen from the
coastal plains through to mountain (+1500 m) elevations. At high
elevations within the source area, temperature effects become more
important than precipitation in determining the forest cover type. Therefore,
it is not possible to fully isolate precipitation signals from temperature
changes. Particularly for the semiarid areas of the Mediterranean, the
reconstruction approach probably cannot distinguish between a reduction in
precipitation and an increase in temperature and potential evapotranspiration (PET) or vice versa.
Similarly, while the concept of reconstructing winter and summer
precipitation separately is very attractive, it may be worth commenting on
some limitations. Although different levels of the severity or length of
summer drought are an important ecological limitation for vegetation,
reconstructing absolute summer precipitation can be difficult because the
severity and length of bioclimatic drought is determined by both temperature and
precipitation. We are dealing with a season that has, by definition, small
amounts of precipitation that drop below the requirements for vegetation
growth. Elevation is also of concern, as lowland systems tend to be
recharged by winter rainfall, but high mountain systems may receive a
significant part of precipitation as snowfall, which is not directly
available to plant life. This may be important in the long term for improving
the interpretation of long-term Holocene changes and contrasts between
different proxies, such as lake levels and speleothems. Although these
issues may initially appear to be of marginal importance, they may
nevertheless have a real influence leading to problems and mismatches
between different proxies (e.g., Davis et al., 2003; Mauri et al., 2015).
Another important point is the question of human impact on the Mediterranean
vegetation during the Holocene. Since human activity has influenced natural
vegetation, distinguishing between vegetation change induced by humans and
climatic change in the Mediterranean is a challenge requiring independent
proxies and approaches. Therefore, links and processes behind societal change
and climate change in the Mediterranean region are being increasingly
investigated (e.g., Holmgren et al., 2016; Gogou et al., 2016; Sadori et al.,
2016a). Here, the behavior of the reconstructed climatic variables between
4000 and 2000 cal yr BP is likely to be influenced by unnatural
ecosystem changes due to human activities such as the forest degradation that
began in the lowlands and progressed to mountainous areas (Carrión et al.,
2010). These human impacts add confounding effects for fossil pollen records
and may lead to slightly biased temperature reconstructions during the late
Holocene, likely biased towards warmer temperatures and lower precipitation.
However, if human activities become more marked at 3000 cal yr BP, they
increase significantly over the last millennia (Sadori et al., 2016), which is
not within the timescale studied here. Moreover, there is strong agreement
between summer precipitation and independently reconstructed lake-level
curves (Magny et al., 2013). For the marine pollen cores, human influence is
much more difficult to interpret given that the source area is so large and
that, in general, anthropic taxa are not found in marine pollen assemblages.
Conclusions
The Mediterranean is particularly sensitive to climate change but the extent
of future change relative to changes during the Holocene remains uncertain.
Here, we present a reconstruction of Holocene precipitation in the
Mediterranean using an approach based on both terrestrial and marine pollen
records, along with a model–data comparison based on a high-resolution
regional model. We investigate climatic trends across the Mediterranean
during the Holocene to test the hypothesis of an alternating north–south
precipitation regime and/or an east–west precipitation dipole. We give
particular emphasis to the reconstruction of seasonal precipitation,
considering the important role it plays in this system.
Climatic trends reconstructed in this study seem to corroborate the
north–south division of precipitation regimes during the Holocene, with wet
conditions in the south–central and eastern Mediterranean and dry conditions
above 45∘ N during the early Holocene, while the opposite pattern
dominates during the late Holocene. This study also shows that a prominent
feature of Holocene climate in the Mediterranean is the east-to-west division
in precipitation, which is strongly linked to the seasonal parameter reconstructed.
During the early Holocene, we observe an east-to-west division with high
summer precipitation in Greece and the eastern Mediterranean and a minimum
over Italy and the western Mediterranean. There was a drying trend in the
Mediterranean from the early Holocene to the late Holocene, particularly in
central and eastern regions, but summers in the east remained wetter than
today. In contrast, the signal for winter precipitation is less spatially
consistent during the early Holocene, but it clearly shows conditions similar to present
day or drier everywhere in the Mediterranean except for in the western
basin during the late Holocene.
The regional climate model outputs show a remarkable qualitative agreement
with our pollen-based reconstructions, although it must be emphasized that
the changes simulated are typically very small or are of questionable
statistical significance. Nevertheless, there are indications that the east-to-west division in summer precipitation reconstructed from the pollen
records does appear to be simulated by the climate model. The model results
also suggest that parts of the eastern Mediterranean experienced conditions similar to
present day or drier in winter during the early and late Holocene
and wetter annual and summer conditions during the early and late
Holocene (both consistent with the paleo-records).
Although this study has used regional climate model data, it must always be
recalled that the regional model's high-resolution output is strongly
constrained by a coarser-resolution global climate model, and the ability of
global models to correctly reproduce large-scale patterns of change in the
Mediterranean over the Holocene remains unclear (e.g., Mauri et al., 2015).
The generally positive comparison between model and data presented here may
therefore simply be fortuitous and not necessarily replicated if the output
from other global climate model simulations was downscaled in a similar way.
However, it is noted that the use of higher-resolution regional climate
models can offer significant advantages for data–model comparison insofar as
they assist in resolving the inherently patchy nature of climate signals
and paleo-records. Notwithstanding the difficulties of correctly modeling
large-scale climate change over the Holocene (with GCMs), we believe that
regional downscaling may still be valuable in facilitating model–data
comparison in regions and/or locations known to be strongly influenced by local
effects (e.g., complex topography).
Data for this paper are available in the Supplement.
The Supplement related to this article is available online at doi:10.5194/cp-13-249-2017-supplement.
The authors declare that they have no conflict of interest.
Acknowledgements
This study is a part of the LAMA ANR Project (MSHE Ledoux, USR 3124, CNRS)
financially supported by the French CNRS (National Centre for Scientific
Research). Simon Goring is currently supported by NSF MacroSystems grant
144-PRJ45LP. This is an ISEM contribution no. 2017-042.
Edited by: J. Guiot
Reviewed by: two anonymous referees
References
Alpert, P., Baldi, M., Ilani, R., Krichak, S., Price, C., Rodó, X.,
Saaroni, H., Ziv, B., Kishcha, P., Barkan, J., Mariotti, A., and Xoplaki, E.:
Relations between climate variability in the Mediterranean region and the
Tropics: ENSO, South Asian and African monsoons, hurricanes and Saharan dust
in: Mediterranean Climate Variability, edited by: Lionello, P., Malanotte-Rizzoli, P., and Boscolo, R., Amsterdam, Elsevier, 149–177, 2006.
Bar-Matthews, M. and Ayalon, A.: Mid-Holocene climate variations revealed by
high-resolution speleothem records from Soreq Cave, Israel and their
correlations with cultural changes, The Holocene, 21, 163–172, 2011.
Bar-Matthews, M., Ayalon, A., Gilmour, M., Matthews, A., and Hawkesworth,
C. J.: Sea-land oxygen isotopic relationships from planktonic foraminifera
and speleothems in the Eastern Mediterranean region and their implication
for paleorainfall during interglacial intervals, Geochim. Cosmochim.
Ac., 67, 3181–3199, 2003.
Bartlein, P. J., Harrison, S. P., Brewer, S., Connor, S., Davis, B. A. S.,
Gajewski, K., Guiot, J., Harrison-Prentice, T.I., Henderson, A., Peyron, O.,
Prentice, I .C., Scholze, M., Seppä, H., Shuman, B., Sugita, S.,
Thompson, R. S., Viau, A. E, Williams, J., and Wu, H.: Pollen-based continental
climate reconstructions at 6 and 21 ka: a global synthesis, Clim. Dynam.,
37, 775–802, 2011.
Bosmans, J. H. C., Drijfhout, S. S., Tuenter, E., Hilgen, F. J., Lourens, L.
J.,
and Rohling, E. J.: Precession and obliquity forcing of the freshwater budget
over the Mediterranean, Quaternary Sci. Rev., 123, 16–30, 2015.Braconnot, P., Otto-Bliesner, B., Harrison, S., Joussaume, S., Peterchmitt,
J.-Y., Abe-Ouchi, A., Crucifix, M., Driesschaert, E., Fichefet, Th., Hewitt,
C. D., Kageyama, M., Kitoh, A., Laîné, A., Loutre, M.-F., Marti, O.,
Merkel, U., Ramstein, G., Valdes, P., Weber, S. L., Yu, Y., and Zhao, Y.:
Results of PMIP2 coupled simulations of the Mid-Holocene and Last Glacial
Maximum – Part 1: experiments and large-scale features, Clim. Past, 3,
261–277, 10.5194/cp-3-261-2007, 2007a.Braconnot, P., Otto-Bliesner, B., Harrison, S., Joussaume, S., Peterchmitt,
J.-Y., Abe-Ouchi, A., Crucifix, M., Driesschaert, E., Fichefet, Th., Hewitt,
C. D., Kageyama, M., Kitoh, A., Loutre, M.-F., Marti, O., Merkel, U.,
Ramstein, G., Valdes, P., Weber, L., Yu, Y., and Zhao, Y.: Results of PMIP2
coupled simulations of the Mid-Holocene and Last Glacial Maximum – Part 2:
feedbacks with emphasis on the location of the ITCZ and mid- and high
latitudes heat budget, Clim. Past, 3, 279–296, 10.5194/cp-3-279-2007,
2007b.
Braconnot, P., Harrison, S., Kageyama, M., Bartlein, J., Masson, V.,
Abe-Ouchi, A., Otto-Bliesner, B., and Zhao, Y.: Evaluation of climate models
using palaeoclimatic data, Nature Climate Change, 2, 417–424, 2012.Brayshaw, D. J., Hoskins, B., and Black, E.: Some physical drivers of changes
in the winter storm tracks over the North Atlantic and Mediterranean during
the Holocene, Philos. T. Roy. Soc. A, 368, 5185–5223, 2010.
Brayshaw, D. J., Rambeau, C. M. C., and Smith, S. J.: Changes in the
Mediterranean climate during the Holocene: insights from global and regional
climate modelling, The Holocene, 21, 15–31, 2011a.
Brayshaw, D. J., Black, E., Hoskins, B., and Slingo, J.: Past climates of the
Middle East, in: Water, Life and Civilisation: Climate, Environment and
Society in the Jordan Valley, edited by: Mithen, S. and Black, E.,
International Hydrology Series. Cambridge University Press, Cambridge,
25–50, 2011b.
Carrión, J. S., Fernández, S., Jiménez-Moreno, G., Fauquette, S.,
Gil-Romera, G., González-Sampériz, P., and Finlayson, C.: The
historical origins of aridity and vegetation degradation in southeastern
Spain, J. Arid Environ., 74, 731–736, 2010.
Cheddadi, R., Yu, G., Guiot, J., Harrison, S. P., and Prentice, I. C.: The
climate of Europe 6000 years ago, Clim. Dynam., 13, 1–9, 1997.
Colmenero-Hidalgo, E., Flores, J.-A., and Sierro, F. J.: Biometry of
Emiliania huxleyi and its biostratigraphic significance in the eastern north
Atlantic Ocean and Western Mediterranean Sea in the last 20 000 years, Mar.
Micropaleontol., 46, 247–263, 2002.
Colombaroli, D., Vannière, B., Chapron, E., Magny, M., and Tinner, W.
Fire–vegetation interactions during the Mesolithic–Neolithic transition at
Lago dell'Accesa, Tuscany, Italy, The Holocene, 18, 679–692, 2008.
Combourieu-Nebout, N., Paterne, M., Turon, J.-L., and Siani, G.: A
high-resolution record of the Last Deglaciation in the Central Mediterranean
Sea: palaeovegetation and palaeohydrological evolution, Quaternary Sci. Rev.,
17, 303–332, 1998.
Combourieu-Nebout, N., Londeix, L., Baudin, F., and Turon, J. L.: Quaternary
marine and continental palaeoenvironments in the Western Mediterranean Sea
(Leg 161, Site 976, Alboran Sea): Palynological evidences, Proceeding of the
Ocean Drilling Project, scientific results, 161, 457–468, 1999.
Combourieu-Nebout, N., Turon, J. L., Zahn, R., Capotondi, L., Londeix, L.,
and Pahnke, K.: Enhanced aridity and atmospheric high pressure stability over
the western Mediterranean during North Atlantic cold events of the past
50 000 years, Geology, 30, 863–866, 2002.Combourieu Nebout, N., Peyron, O., Dormoy, I., Desprat, S., Beaudouin, C.,
Kotthoff, U., and Marret, F.: Rapid climatic variability in the west
Mediterranean during the last 25 000 years from high resolution pollen data,
Clim. Past, 5, 503–521, 10.5194/cp-5-503-2009, 2009.Combourieu-Nebout, N., Peyron, O., Bout-Roumazeilles, V., Goring, S., Dormoy,
I., Joannin, S., Sadori, L., Siani, G., and Magny, M.: Holocene vegetation
and climate changes in the central Mediterranean inferred from a
high-resolution marine pollen record (Adriatic Sea), Clim. Past, 9,
2023–2042, 10.5194/cp-9-2023-2013, 2013.
Davis, B. A. S. and Brewer, S.: Orbital forcing and role of the latitudinal
insolation/temperature gradient, Clim. Dynam., 32, 143–165, 2009.
Davis, B. A. S., Brewer, S., Stevenson, A. C., and Guiot, J.: The
temperature of Europe during the Holocene reconstructed from pollen data,
Quaternary Sci. Rev., 22, 1701–1716, 2003.
De Santis, V. and Caldara, M.: The 5.5–4.5 kyr climatic transition as
recorded by the sedimentation pattern of coastal deposits of the Apulia
region, southern Italy, The Holocene, 25, 1313–1329, 2015.Desprat, S., Combourieu-Nebout, N., Essallami, L., Sicre, M. A., Dormoy, I.,
Peyron, O., Siani, G., Bout Roumazeilles, V., and Turon, J. L.: Deglacial and
Holocene vegetation and climatic changes in the southern Central
Mediterranean from a direct land-sea correlation, Clim. Past, 9, 767–787,
10.5194/cp-9-767-2013, 2013.
Djamali, M., Gambin, B., Marriner, N., Andrieu-Ponel, V., Gambin, T.,
Gandouin, E., Médail, F., Pavon, D., Ponel, P., and Morhange, C.:
Vegetation dynamics during the early to mid-Holocene transition in NW Malta,
human impact versus climatic forcing, Veg. Hist. Archaeobot., 22, 367–380,
2013.Dormoy, I., Peyron, O., Combourieu Nebout, N., Goring, S., Kotthoff, U.,
Magny, M., and Pross, J.: Terrestrial climate variability and seasonality
changes in the Mediterranean region between 15 000 and 4000 years BP
deduced from marine pollen records, Clim. Past, 5, 615–632,
10.5194/cp-5-615-2009, 2009.
Drescher-Schneider, R., de Beaulieu, J.L., Magny, M., Walter-Simonnet, A.V.,
Bossuet, G., Millet, L. Brugiapaglia, E., and Drescher A.: Vegetation
history, climate and human impact over the last 15 000 years at Lago
dell'Accesa, Veg. Hist. Archaeobot., 16, 279–299, 2007.
Eastwood, W. J., Leng, M., Roberts, N., and Davis B.: Holocene climate change
in the eastern Mediterranean region: a comparison of stable isotope and
pollen data from Lake Gölhisar, southwest Turkey, J. Quaternary Sci., 22,
327–341, 2007.
Finné, M., Holmgren, K., Sundqvist, H. S., Weiberg, E., and Lindblom, M.:
Climate in the eastern Mediterranean, and adjacent regions, during the past
6000 years, J. Archaeol. Sci., 38, 3153–3173, 2011.Fischer, N. and Jungclaus, J. H.: Evolution of the seasonal temperature cycle
in a transient Holocene simulation: orbital forcing and sea-ice, Clim. Past,
7, 1139–1148, 10.5194/cp-7-1139-2011, 2011.
Fletcher, W. J. and Sánchez Goñi, M. F.: Orbital- and
sub-orbital-scale climate impacts on vegetation of the western Mediterranean
basin over the last 48,000 yr, Quaternary Res., 70, 451–464, 2008.Fletcher, W. J., Sanchez Goñi, M. F., Peyron, O., and Dormoy, I.: Abrupt
climate changes of the last deglaciation detected in a Western Mediterranean
forest record, Clim. Past, 6, 245–264, 10.5194/cp-6-245-2010, 2010.
Fletcher, W. J., Debret, M., and Sanchez Goñi, M. F.: Mid-Holocene
emergence of a low-frequency millennial oscillation in western Mediterranean
climate: Implications for past dynamics of the North Atlantic atmospheric
westerlies, The Holocene, 23, 153–166, 2013.Gambin, B., Andrieu-Ponel, V., Médail, F., Marriner, N., Peyron, O.,
Montade, V., Gambin, T., Morhange, C., Belkacem, D., and Djamali, M.: 7300
years of vegetation history and climate for NW Malta: a Holocene perspective,
Clim. Past, 12, 273–297, 10.5194/cp-12-273-2016, 2016.
Geraga, M., Ioakim, C., Lykousis, V., Tsaila-Monopolis, S., and Mylona, G.:
The high-resolution palaeoclimatic and palaeoceanographic history of the last
24,000 years in the central Aegean Sea, Greece, Palaeogeogr. Palaeocl., 287,
101–115, 2010.
Giorgi, F. and Lionello, P.: Climate change projections for the Mediterranean
region, Glob. Planet. Change, 63, 90–104, 2008.
Gogou, A., Bouloubassi, I., Lykousis, V., Arnaboldi, M., Gaitani, P., and
Meyers, P.A.: Organic geochemical evidence of abrupt late glacial-Holocene
climate changes in the North Aegean Sea, Palaeogeogr. Palaeocl., 256, 1–20,
2007.
Gogou, A., Triantaphyllou, M., Xoplaki, E., Izdebski, A., Parinos, C.,
Dimiza, M., Bouloubassi, I., Luterbacher, J., Kouli, K., Martrat, B., Toreti,
A., Fleitmann, D., Rousakis, G., Kaberi, H., Athanasiou, M., and Lykousis,
V.: Climate variability and socio-environmental changes in the northern
Aegean (NE Mediterranean) during the last 1500 years, Quaternary Sci. Rev.,
136, 209–228, 2016.
Guiot, J.: Methodology of the last climatic cycle reconstruction in France
from pollen data, Palaeogeogr. Palaeocl., 80, 49–69, 1990.Guiot, J. and Kaniewski, D.: The Mediterranean Basin and Southern Europe in a
warmer world: what can we learn from the past?, Front. Earth Sci., 3, 28, 10.3389/feart.2015.00028, 2015.Hargreaves, J. C., Annan, J. D., Ohgaito, R., Paul, A., and Abe-Ouchi, A.:
Skill and reliability of climate model ensembles at the Last Glacial Maximum
and mid-Holocene, Clim. Past, 9, 811–823, 10.5194/cp-9-811-2013, 2013.Heiri, O., Brooks, S. J., Renssen, H., et al.: Validation of climate
model-inferred regional temperature change for late-glacial Europe, Nat.
Commun., 5, 4914, 10.1038/ncomms5914, 2014.
Heusser, L. E. and Balsam W. L.: Pollen distribution in the N.E. Pacific
ocean, Quaternary Res., 7, 45–62, 1977.
Hewitt, C. D., Senior, C. A., and Mitchell, J. F. B. :The impact of dynamic
sea-ice on the climatology and sensitivity of a GCM: A study of past, present
and future climates, Clim. Dynam., 17, 655–668, 2001.
Holmgren, K., Gogou, A., Izdebski, A., Luterbacher, J., Sicre, M. A., and
Xoplaki, A.: Mediterranean Holocene Climate, Environment and Human Societies,
Quaternary Sci. Rev., 136, 1–4, 2016.
Ioakim, C., Triantaphyllou, M., Tsaila-Monopolis, S., and Lykousis, V.: New
micropalaeontological records of Eastern Mediterranean marine sequences
recovered offshore of Crete, during HERMES cruise and their palaeoclimatic
paleoceanographic significance, Acta Naturalia de “L'Ateneo Parmense”, in:
Earth System Evolution and the Mediterranean Area from 23 Ma to the Present,
45, p. 152, 2009.
Jimenez-Moreno, G., Rodriguez-Ramirez, A., Perez-Asensio, J.N., Carrion,
J.S., Lopez-Saez, J.A, Villarías-Robles J., Celestino-Perez, S.,
Cerrillo-Cuenca, E., Leon, A., and Contreras, C.: Impact of late-Holocene
aridification trend, climate variability and geodynamic control on the
environment from a coastal area in SW Spain, The Holocene, 25, 607–617, 2015.Joannin, S., Brugiapaglia, E., de Beaulieu, J.-L., Bernardo, L., Magny, M.,
Peyron, O., Goring, S., and Vannière, B.: Pollen-based reconstruction of
Holocene vegetation and climate in southern Italy: the case of Lago
Trifoglietti, Clim. Past, 8, 1973–1996, 10.5194/cp-8-1973-2012, 2012.Joannin, S., Vannière, B., Galop, D., Peyron, O., Haas, J. N., Gilli, A.,
Chapron, E., Wirth, S. B., Anselmetti, F., Desmet, M., and Magny, M.: Climate
and vegetation changes during the Lateglacial and early-middle Holocene at
Lake Ledro (southern Alps, Italy), Clim. Past, 9, 913–933,
10.5194/cp-9-913-2013, 2013.
Kotthoff, U., Pross, J., Müller, U. C., Peyron, O., Schmiedl, G., and
Schulz, H.: Climate dynamics in the borderlands of the Aegean Sea during
formation of Sapropel S1 deduced from a marine pollen record, Quaternary Sci.
Rev., 27, 832–845, 2008.
Kotthoff, U., Koutsodendris, A., Pross, J., Schmiedl, G., Bornemann, A.,
Kaul, C., Marino, G., Peyron, O., and Schiebel, R.: Impact of late glacial
cold events on the Northern Aegean region reconstructed from marine and
terrestrial proxy data, J. Quaternary Sci., 26, 86–96, 2011.
Kouli, K., Gogou, A., Bouloubassi, I., Triantaphyllou, M.V., Ioakim, Chr,
Katsouras, G., Roussakis, G., and Lykousis, V.: Late postglacial
paleoenvironmental change in the northeastern Mediterranean region: Combined
palynological and molecular biomarker evidence, Quatern. Int., 261, 118–127,
2012.
Kuhnt, T., Schmiedl, G., Ehrmann, W., Hamann, Y., and Andersen, N.: Stable
isotopic composition of Holocene benthic foraminifers from the eastern
Mediterranean Sea: past changes in productivity and deep water oxygenation,
Palaeogeogr. Palaeocl., 268, 106–115, 2008.
Lionello, P. (Ed.): The climate of the Mediterranean region: From the past to
the future, Elsevier, ISBN: 9780124160422, 2012.
Lionello, P., Malanotte-Rizzoli, P., Boscolo, R., et al.: The Mediterranean
climate: An overview of the main characteristics and issues, in:
Mediterranean Climate Variability, edited by: Lionello, P.,
Malanotte-Rizzoli, P., and Boscolo, R., Developments in Earth &
Environmental Sciences, Elsevier, 4, 1–26, 2006.
Luterbacher, J., García-Herrera, R., Akcer-On, S., et al.: A review of
2000 years of paleoclimatic evidence in the Mediterranean, in: The Climate of
the Mediterranean region: From the past to the future, edited by: Lionello,
P., Elsevier, Amsterdam, the Netherlands, 2012.
Magny, M., de Beaulieu, J. L., Drescher-Schneider, R., Vannière, B.,
Walter-Simonnet, A. V., Miras, Y., Millet, L., Bossuet, G., Peyron, O.,
Brugiapaglia, E., and Leroux, A.: Holocene climate changes in the central
Mediterranean as recorded by lake-level fluctuations at Lake Accesa (Tuscany,
Italy), Quaternary Sci. Rev. 26, 1736–1758, 2007.
Magny, M., Vannière, B., Zanchetta, G., Fouache, E., Touchais, G.,
Petrika, L., Coussot, C., Walter-Simonnet, A. V., and Arnaud, F.: Possible
complexity of the climatic event around 4300–3800 cal BP in the central
and western Mediterranean, The Holocene, 19, 823–833, 2009.
Magny, M., Vannière, B., Calo, C., Millet, L., Leroux, A., Peyron, O.,
Zanchetta, G., La Mantia, T., and Tinner, W.: Holocene hydrological changes
in south-western Mediterranean as recorded by lake-level fluctuations at Lago
Preola, a coastal lake in southern Sicily, Italy, Quaternary Sci. Rev., 30,
2459–2475, 2011.
Magny, M., Joannin, S., Galop, D., Vannière, B., Haas, J. N., Bassetti,
M., Bellintani, P., Scandolari, R., and Desmet, M.: Holocene
palaeohydrological changes in the northern Mediterranean borderlands as
reflected by the lake-level record of Lake Ledro, northeastern Italy,
Quaternary Res., 77, 382–396, 2012a.
Magny, M., Peyron, O., Sadori, L., Ortu, E., Zanchetta, G., Vannière,
B., and Tinner, W.: Contrasting patterns of precipitation seasonality during
the Holocene in the south- and north-central Mediterranean, J. Quaternary
Sci., 27, 290–296, 2012b.Magny, M., Combourieu-Nebout, N., de Beaulieu, J. L., Bout-Roumazeilles, V.,
Colombaroli, D., Desprat, S., Francke, A., Joannin, S., Ortu, E., Peyron, O.,
Revel, M., Sadori, L., Siani, G., Sicre, M. A., Samartin, S., Simonneau, A.,
Tinner, W., Vannière, B., Wagner, B., Zanchetta, G., Anselmetti, F.,
Brugiapaglia, E., Chapron, E., Debret, M., Desmet, M., Didier, J., Essallami,
L., Galop, D., Gilli, A., Haas, J. N., Kallel, N., Millet, L., Stock, A.,
Turon, J. L., and Wirth, S.: North-south palaeohydrological contrasts in the
central Mediterranean during the Holocene: tentative synthesis and working
hypotheses, Clim. Past, 9, 2043–2071, 10.5194/cp-9-2043-2013, 2013.
Mauri, A., Davis, B., Collins, P. M., and Kaplan, J.: The climate of Europe
during the Holocene: A gridded pollen-based reconstruction and its
multi-proxy evaluation, Quaternary Sci. Rev., 112, 109–127,
2015.Mauri, A., Davis, B. A. S., Collins, P. M., and Kaplan, J. O.: The influence
of atmospheric circulation on the mid-Holocene climate of Europe: a
data-model comparison, Clim. Past, 10, 1925–1938,
10.5194/cp-10-1925-2014, 2014.Morrill, C., Anderson, D. M., Bauer, B. A., Buckner, R., Gille, E. P., Gross,
W. S., Hartman, M., and Shah, A.: Proxy benchmarks for intercomparison of 8.2
ka simulations, Clim. Past, 9, 423–432, 10.5194/cp-9-423-2013, 2013.
Naughton, F., Sanchez Goñi, M.F., Desprat, S., Turon, J.L., Duprat, J.,
Malaizé, B., Joli, C., Cortijo, E., Drago, T., and Freitas, M.C.:
Present-day and past (last 25 000 years) marine pollen signal off western
Iberia, Mar. Micropaleontol., 62, 91–114, 2007.Nourelbait, M., Rhoujjati, A., Benkaddour, A., Carré, M., Eynaud, F.,
Martinez, P., and Cheddadi, R.: Climate change and ecosystems dynamics over
the last 6000 years in the Middle Atlas, Morocco, Clim. Past, 12, 1029–1042,
10.5194/cp-12-1029-2016, 2016.
Peyron, O., Goring, S., Dormoy, I., Kotthoff, U., Pross, J., de Bealieu, J.
L., Drescher-Schneider, R., and Magny, M.: Holocene seasonality changes in
the central Mediterranean region reconstructed from the pollen sequences of
Lake Accesa (Italy) and Tenaghi Philippon (Greece), The Holocene, 21, 131–146,
2011.Peyron, O., Magny, M., Goring, S., Joannin, S., de Beaulieu, J.-L.,
Brugiapaglia, E., Sadori, L., Garfi, G., Kouli, K., Ioakim, C., and
Combourieu-Nebout, N.: Contrasting patterns of climatic changes during the
Holocene across the Italian Peninsula reconstructed from pollen data, Clim.
Past, 9, 1233–1252, 10.5194/cp-9-1233-2013, 2013.
Pope, V. D., Gallani, M. L., Rowntree, R. R., and Stratton, R. A.: The impact
of new physical parameterizations in the Hadley Centre climate model: HadAM3,
Clim. Dynam., 16, 123–146, 2000.
Pross, J., Kotthoff, U., Müller, U.C., Peyron, O., Dormoy, I., Schmiedl,
G., Kalaitzidis, S., and Smith, A. M.: Massive perturbation in terrestrial
ecosystems of the Eastern Mediterranean region associated with the 8.2 kyr
climatic event, Geology, 37, 887–890, 2009.
Pross, J., Koutsodendris, A., Christanis, K., Fischer, T., Fletcher, W. J.,
Hardiman, M., Kalaitzidis, S., Knipping, M., Kotthoff, U., Milner, A. M.,
Müller, U. C., Schmiedl, G., Siavalas, G., Tzedakis, P. C., and Wulf, S.:
The 1.35-Ma-long terrestrial climate archive of Tenaghi Philippon,
northeastern Greece: Evolution, exploration and perspectives for future
research, Newsl. Stratigr., 48, 253–276, 2015.
Ramos-Román, M. J., Jiménez-Moreno, G., Anderson, R. S.,
García-Alix, A., Toney, J. L., Jiménez-Espejo, F. J., and
Carrión, J. S.: Centennial-scale vegetation and North Atlantic
Oscillation changes during the Late Holocene in the southern Iberia,
Quaternary Sci. Rev., 143, 84–98, 2016.
Renssen, H., Seppa, H., Crosta, X., Goosse, H., and Roche, D.M.: Global
characterization of the Holocene Thermal Maximum, Quateranry Sci. Rev., 48,
7–19, 2012.
Roberts, N., Brayshaw, D., Kuzucuoğlu, C., Perez, R., and Sadori, L.: The
mid-Holocene climatic transition in the Mediterranean: Causes and
consequences, The Holocene, 21, 3–13, 2011.
Roberts, N., Moreno, A., Valero-Garces, B. L., et al.: Palaeolimnological
evidence for an east-west climate see-saw in the mediterranean since AD 900,
Glob. Planet. Change, 84/85, 23–34, 2012.
Rohling, E. J., Cane, T. R., Cooke, S., et al.: African monsoon variability
during the previous interglacial maximum, Earth Planet. Sc. Lett., 202,
61–75, 2002.
Sadori, L. and Giardini, M.: Charcoal analysis, a method to study vegetation
and climate of the Holocene: The case of Lago di Pergusa, Sicily (Italy),
Geobios-Lyon, 40, 173–180, 2007.
Sadori, L. and Narcisi, B.: The postglacial record of environmental history
from Lago di Pergusa, Sicily, The Holocene, 11, 655–671, 2001.
Sadori, L., Zanchetta, G., and Giardini, M.: Last Glacial to Holocene
palaeoenvironmental evolution at Lago di Pergusa (Sicily, Southern Italy) as
inferred by pollen, microcharcoal, and stable isotopes, Quatern. Int., 181,
4–14, 2008.
Sadori, L., Jahns, S., and Peyron, O.: Mid-Holocene vegetation history of the
central Mediterranean, The Holocene, 21, 117–129, 2011.Sadori, L., Ortu, E., Peyron, O., Zanchetta, G., Vannière, B., Desmet,
M., and Magny, M.: The last 7 millennia of vegetation and climate changes at
Lago di Pergusa (central Sicily, Italy), Clim. Past, 9, 1969–1984,
10.5194/cp-9-1969-2013, 2013.
Sadori, L., Giraudi, C. Masi, A., Magny, M., Ortu, E., Zanchetta, G., and
Izdebski, A.: Climate, environment and society in southern Italy during the
last 2000 years, A review of the environmental, historical and archaeological
evidence, Quaternary Sci. Rev., 136, 173–188, 2016a.Sadori, L., Koutsodendris, A., Panagiotopoulos, K., Masi, A., Bertini, A.,
Combourieu-Nebout, N., Francke, A., Kouli, K., Joannin, S., Mercuri, A. M.,
Peyron, O., Torri, P., Wagner, B., Zanchetta, G., Sinopoli, G., and Donders,
T. H.: Pollen-based paleoenvironmental and paleoclimatic change at Lake Ohrid
(south-eastern Europe) during the past 500 ka, Biogeosciences, 13,
1423–1437, 10.5194/bg-13-1423-2016, 2016b.
Schemmel, F., Niedermeyer, E. M., Schwab-Lavrič, V., Gleixner, G., Pross,
J., and Mulch, A.: Plant-wax dD values record changing Eastern Mediterranean
atmospheric circulation patterns during the 8.2 ka BP climatic event,
Quaternary Sc. Rev., 133, 96–107, 2016.
Stevens, L. R., Ito, E., Schwalb, A., and Wright, H. E.: Timing of
atmospheric precipitation in the Zagros Mountains inferred from a multi-proxy
record from Lake Mirabad, Iran, Quateranry Res., 66, 494–500, 2006.Tarroso, P., Carrión, J., Dorado-Valiño, M., Queiroz, P., Santos, L.,
Valdeolmillos-Rodríguez, A., Célio Alves, P., Brito, J. C., and
Cheddadi, R.: Spatial climate dynamics in the Iberian Peninsula since
15 000 yr BP, Clim. Past, 12, 1137–1149, 10.5194/cp-12-1137-2016,
2016.
Triantaphyllou, V., Antonarakou, A., Kouli, K., et al.: Late
Glacial–Holocene ecostratigraphy of the south-eastern Aegean Sea, based on
plankton and pollen assemblages, Geo-Mar. Lett., 29, 249–267, 2009a.
Triantaphyllou, M. V., Ziveri, P., Gogou, A., Marino, G., Lykousis, V.,
Bouloubassi, I., Emeis, K.-C., Kouli, K., Dimiza, M., Rosell-Mele, A.,
Papanikolaou, M., Katsouras, G., and Nunez, N.: Late Glacial-Holocene climate
variability at the south-eastern margin of the Aegean Sea, Mar. Geol., 266,
182–197, 2009b.
Triantaphyllou, M. V., Gogou, A, Bouloubassi, I., Dimiza, M, Kouli, K.,
Rousakis, A. G., Kotthoff, U., Emeis, K. C., Papanikolaou, M., Athanasiou,
M., Parinos, C., Ioakim, C. V., and Lykousis, V.: Evidence for a warm and
humid Mid-Holocene episode in the Aegean and northern Levantine Seas (Greece,
NE Mediterranean), Reg. Environ. Change, 14, 1697–1712, 2014.
Triantaphyllou, M. V., Gogou, A., Dimiza, M. D., Kostopoulou, S., Parinos,
C., Roussakis, G., Geraga, M., Bouloubassi, I., Fleitmann, D., Zervakis, V.,
Velaoras, D., Diamantopoulou, A., Sampataki, A., and Lykousis, V.: Holocene
Climate Optimum centennial-scale paleoceanography in the NE Aegean Sea
(Mediterranean Sea), Geo-Mar. Lett., 36, 51–66, 2016.
Trigo, R. M., Xoplaki, E., Zorita, E., Luterbacher, J., Krichak, S. O., Alpert,
P., Jacobeit, Saenz, J., Fernandez, J., Gonzalez-Rouco, F, Garcia-Herrera, R.,
Rodo, X., Brunetti, M., Nanni, T., Maugeri, M., Turkes, M., Gimeno, L., Ribera, P.,
Brunet, M., Trigo, I. F., Crepon, M., and Mariotti, A: Relations between
variability in the Mediterranean region and Mid-latitude variability, in: The
Mediterranean Climate: An overview of the main characteristics and issues,
edited by: Lionello, P., Malanotte-Rizzoli, P., and Boscolo, R., Elsevier,
Amsterdam, 2006.
Tzedakis, P. C.: Seven ambiguities in the Mediterranean palaeoenvironmental
narrative, Quaternary Sci. Rev., 26, 2042–2066, 2007.
Vannière, B., Power, M. J., Roberts, N., Tinner, W., Carrion, J., Magny,
M., Bartlein, P., and Contributors Data: Circum-Mediterranean fire activity
and climate changes during the mid Holocene environmental transition
(8500–2500 cal yr BP), The Holocene, 21, 53–73, 2011.Vannière, B., Magny, M., Joannin, S., Simonneau, A., Wirth, S. B.,
Hamann, Y., Chapron, E., Gilli, A., Desmet, M., and Anselmetti, F. S.:
Orbital changes, variation in solar activity and increased anthropogenic
activities: controls on the Holocene flood frequency in the Lake Ledro area,
Northern Italy, Clim. Past, 9, 1193–1209, 10.5194/cp-9-1193-2013, 2013.
Verheyden, S., Nader, F. H., Cheng, H. J., Edwards, L. R., and Swennen, R.:
Paleoclimate reconstruction in the Levant region from the geochemistry of a
Holocene stalagmite from the Jeita cave, Lebanon, Quaternary Res., 70,
368–381, 2008.
Walczak, I. W., Baldini, J. U. L., Baldini, L. M., Mcdermott, F., Marsden,
S., Standish, C. D, Richards, D. A., Andreo, B., and Slater, J.:
Reconstructing high-resolution climate using CT scanning of unsectioned
stalagmites: A case study identifying the mid-Holocene onset of the
Mediterranean climate in southern Iberia, Quaternary Sci. Rev., 127,
117–128, 2015.
Wilks, D. S.: Statistical methods in the atmospheric sciences (Academic
Press, San Diego, CA), 1995.
Wood, S. N.: Fast stable restricted maximum likelihood and marginal
likelihood estimation of semiparametric generalized linear models, J. R.
Stat. Soc., 73, 3–36, 2011.
Wu, H., Guiot, J., Brewer, S., and Guo, Z.: Climatic changes in Eurasia and
Africa at the Last Glacial Maximum and mid-Holocene: reconstruction from
pollen data using inverse vegetation modelling, Clim. Dynam., 29, 211–229,
2007.Zanchetta, G., Borghini, A., Fallick, A. E., Bonadonna, F .P., and Leone, G.:
Late Quaternary palaeohydrology of Lake Pergusa (Sicily, southern Italy) as
inferred by stable isotopes of lacustrine carbonates, J. Paleolimnol., 38,
227–239, 2007.
Zhornyak, L. V., Zanchetta, G., Drysdale, R. N., Hellstrom, J. C., Isola, I.,
Regattieri, E., Piccini, L., Baneschi, I., and Couchoud, I.: Stratigraphic
evidence for a “pluvial phase” between ca. 8200–7100 ka from Renella cave
(Central Italy), Quaternary Sci. Rev., 30, 409–417, 2011.