Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009

Decoding Mediterranean climate variability

using lake sediments

Decoding Mediterranean climate variability

using lake sediments

Daniel Ariztegui

Section of Earth and Environmental SciencesUniversity of GenevaSwitzerlanddaniel.ariztegui@unige.ch

Daniel Ariztegui

Section of Earth and Environmental SciencesUniversity of GenevaSwitzerlanddaniel.ariztegui@unige.ch

Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009

Decoding

Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009

A NATURALIST'S VOYAGE ROUND THE WORLD First Edition - May 1860

The Great Drought was very well described by Darwin

…During this time so little rain fell, that the vegetation failed; the brooks were dried up, and the whole country assumed the appearance of a dusty high-road… …Very great numbers of birds, wild animals, cattle, and horses perished from the want of food and water… The smaller streams in the Pampas were paved with a breccias of bones… …What would be the opinion of a geologist, viewing such an enormous collection of bones, of all kinds of animals and of all ages, thus embedded in one thick earthy mass?...

Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009

Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009

Decode : verb(trans.)

convert (a coded message)

into intelligible language

Decode : verb(trans.)

convert (a coded message)

into intelligible language

PROXY

modern atmospheric circulation

North Atlantic

ClimateThe North Atlantic Oscillation (NAO)

negative (-)positive (+)

The NAO index is defined as the anomalous difference between the polar low and the subtropical high during the winter season (December through March)

www.ldeo.columbia.edu/NAO/

modern atmospheric circulation

ClimateThe North Atlantic Oscillation (NAO)

The NAO index is defined as the anomalous difference between the polar low and the subtropical high during the winter season (December through March)

www.ldeo.columbia.edu/NAO/

modern atmospheric circulation

1860 1880 1900 1920 1940 1960 1980 2000

(+) dry in the Mediterranean

(-) moist air into the Mediterranean

The North Atlantic Oscillation (NAO) in the Mediterranean realm

How far west can be tracked ?

modern atmospheric circulation

Was this modern climate feature active during glacial intervals?

modern atmospheric circulation

Lake Albano

North Atlantic

Lake Albano

seismo-stratigraphy and core location

after Chondrogianni et al., 2004

high-resolution window into the LGM

core correlation and chronology

after Chondrogianni et al., 2004

Lake Albano high-resolution window into the LGM

Lake Albano high-resolution window into the LGM

Lithology

after Chondrogianni et al., 2004

Lake Albano high-resolution window into the LGM

after Chondrogianni et al., 2004

North Atlantic Oscillation

(NAO)

Lake Albano high-resolution window into the LGM

periodical changes in productivity/sedimentation

during LGM

after Chondrogianni et al., 2004

Centennial-millennial changes four alternating cold and warm

intervals between H1 and H2

Decadal-interdecadal changes moisture fluctuations associated

with NAO and/or ENSO like mechanisms

Lake Albano high-resolution window into the LGM

The North Atlantic Oscillation (NAO) in the Mediterranean realm

atmospheric circulation

How far west can be tracked ?

Was this modern climate feature active during glacial intervals?

modern atmospheric circulation

Lake Butrint

North Atlantic

Lake Butrint high-resolution window into the last three centuries

Lake Butrint

Albania

Greece

Corfu

Italy

MediterraneanSea

Lake Butrint high-resolution window into the last three centuries

Corfu

Albania

Lake Butrint

Ioni

an S

ea

1 km

Lake Butrint high-resolution window into the last three centuries

sedimentarycores

referencecore

Lake Butrint high-resolution window into the last three centuries

B 00-2 B 00-3

Excellent core to core correlation

• laminated facies

• homogeneous facies

Lake Butrint high-resolution window into the last three centuries

Depth (cm)

30

20

10

0

Magnetic susceptibility

0

60

120Cs-137(mBq/g)

19631986 1917 1872 18111794

Years AD

0 10 20 30 40 5060 70 80 90 100 110 120 130 140 150 160

1.6

1.4

1.2

1.0

Density (g/cm3)

1741

Ariztegui et al., in review

Lake Butrint high-resolution window into the last three centuries

1 cm

one

ye

ar

1 µm1 µm

1 mm 1 mmgr

ay

laye

rda

rk b

row

n la

yer

whi

te

laye

r

SpringSpring

AutumnAutumn

SummerSummer

WinterWinterPennate diatoms

centric diatoms

carbonate crystals

allochthonous OM

autochthonous OM

star-shaped aragonitesedi

men

t cy

cle

one

ye

ar

1905

1893

Lake Butrint high-resolution window into the last three centuries

Ariztegui et al., in reviewDepth (cm)

0

2

4TOC

(%)

19631986

-30 .0

- 24.0

- 26.0

- 28.0

13C(OM)

(‰)

1917 1872 1811 1794Years AD

0

Oxygen Index(mgCO2 g -1 TOC)

200

400

C/NC/N9

11

13

15N(OM)

(‰)

15N(OM)

(‰)4.0

6.0

2.0

1741

0

100 Hydrogen Index(mgHC g -1 TOC)

Hydrogen Index(mgHC g -1 TOC)

200

50

150

0

- 4.0

- 8.0

18O(carbonate)

(‰)

- 4.0

0

- 2.013C(carbonate)

(‰)

13C(carbonate)

(‰)

- 6.00 20 40 60 80 100 120 140 160

Lake Butrint high-resolution window into the last three centuries

Dep

th

(cm

)

10

20

30

40

50

2000

1917

1 µm

aragonitelow

Mg calcite

1943

1986

1947

1929

1913

1 µm

1 µm

0

Ariztegui et al., in review

Lake Butrint high-resolution window into the last three centuries

number of lamina

0

0.4

0.8data analyzedraw datamobile mean

thickness(cm)

20 40 60 80 100 120 140 160 180 200 220 240 2600- 0.4

Climate

Thickness of the gray lamina

year 2000 year 1740

Lake Butrint high-resolution window into the last three centuries

period (calendar years)

Climate

Spectral analyses

100 2000

0.14

0.04

0.10

0.08

101 5

spectraldensity

3.5 years = NAO

Lake Butrint high-resolution window into the last three centuries

The land-sea interface

influence of the NAO index

increasing evaporation for the last part of the 20 century (positive index)

but…

anthropogenic impact trigger the most recent changes in salinity

The North Atlantic Oscillation (NAO) in the Mediterranean realm

atmospheric circulation

How far west can be tracked ?

Was this modern climate feature active during glacial intervals?YES shifting temperature, wind directions and source of moisture

The Ionian and Adriatic Sea

THANKS

• EU-Project PALICLAS

• Swiss National Science Foundation

• Albanian Geological Survey

• Université de Genève

• ETH Zürich

Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009

Lake Butrint high-resolution window into the last three centuries