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Decoding Mediterranean climate variability using lake sediments. Daniel Ariztegui Section of Earth and Environmental Sciences University of Geneva Switzerland daniel.ariztegui@unige.ch. Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009. Decoding.
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Decoding Mediterranean climate variability using lake sediments Daniel Ariztegui Section of Earth and Environmental Sciences University of Geneva Switzerland daniel.ariztegui@unige.ch Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009
Decoding Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009
A NATURALIST'S VOYAGE ROUND THE WORLD First Edition - May 1860 Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009
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 2009
Decode: verb(trans.) convert (a coded message) into intelligible language PROXY Clima en España: Pasado, Presente y Futuro – Madrid, 11-13 February 2009
North Atlantic modern atmospheric circulation
Climate The 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) positive (+) negative (-) www.ldeo.columbia.edu/NAO/ modern atmospheric circulation
Climate The 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) (+) dry in the Mediterranean (-) moist air into the Mediterranean 1860 1880 1900 1920 1940 1960 1980 2000 www.ldeo.columbia.edu/NAO/ modern atmospheric circulation
The North Atlantic Oscillation (NAO) in the Mediterranean realm Was this modern climate feature active during glacial intervals? How far west can be tracked ? modern atmospheric circulation
North Atlantic Lake Albano modern atmospheric circulation
seismo-stratigraphy and core location after Chondrogianni et al., 2004 Lake Albano high-resolution window into the LGM
core correlation and chronology after Chondrogianni et al., 2004 Lake Albano high-resolution window into the LGM
Lithology Lake Albano high-resolution window into the LGM
after Chondrogianni et al., 2004 Lake Albano high-resolution window into the LGM
periodical changes in productivity/sedimentation during LGM North Atlantic Oscillation (NAO) after Chondrogianni et al., 2004 Lake Albano high-resolution window into the LGM
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 after Chondrogianni et al., 2004 Lake Albano high-resolution window into the LGM
The North Atlantic Oscillation (NAO) in the Mediterranean realm Was this modern climate feature active during glacial intervals? How far west can be tracked ? atmospheric circulation
North Atlantic Lake Butrint modern atmospheric circulation
Italy Albania Lake Butrint Corfu Greece Mediterranean Sea Lake Butrint high-resolution window into the last three centuries
Corfu Lake Butrint Ionian Sea Albania 1 km Lake Butrint high-resolution window into the last three centuries
sedimentary cores reference core 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
Years AD 1986 1963 1917 1872 1811 1794 1741 30 Magnetic susceptibility 20 10 0 1.6 Density (g/cm3) 1.4 1.2 1.0 Cs-137 (mBq/g) 120 60 0 Depth (cm) Ariztegui et al., in review Lake Butrint high-resolution window into the last three centuries 0 10 20 30 40 60 50 70 80 90 100 110 120 130 140 150 160
1905 1 mm 1 mm one year 1 cm 1 µm 1 µm 1893 gray layer Pennate diatoms centric diatoms carbonate crystals allochthonous OM autochthonous OM star-shaped aragonite Winter one year Autumn sediment cycle dark brown layer Summer white layer Spring Lake Butrint high-resolution window into the last three centuries
Years AD 1986 1963 1917 1872 1811 1794 1741 4 sedimentary organic matter TOC (%) 2 200 0 150 Hydrogen Index (mgHC g -1 TOC) 100 Oxygen Index (mgCO2 g -1 TOC) 50 400 0 200 0 13 11 C/N 9 13C(OM) (‰) - 24.0 - 26.0 - 28.0 6.0 -30 .0 15N(OM) (‰) 4.0 18O(carbonate) (‰) 2.0 0 authigenic carbonates - 4.0 0 13C(carbonate) (‰) - 8.0 - 2.0 - 4.0 - 6.0 0 20 40 60 80 100 120 160 140 Depth (cm) Ariztegui et al., in review Lake Butrint high-resolution window into the last three centuries
2000 0 1986 10 aragonite Depth (cm) 20 1 µm 1947 1943 30 1929 1 µm low Mg calcite 1917 40 1913 1 µm Ariztegui et al., in review 50 Lake Butrint high-resolution window into the last three centuries
Climate Thickness of the gray lamina thickness (cm) data analyzed raw data 0.8 mobile mean 0.4 0 - 0.4 0 20 40 60 80 100 120 140 160 180 200 220 240 260 number of lamina year 2000 year 1740 Lake Butrint high-resolution window into the last three centuries
3.5 years = NAO Climate Spectral analyses 0.14 0.10 spectral density 0.08 0.04 0 1 5 10 100 200 period (calendar years) 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 Lake Butrint high-resolution window into the last three centuries
The North Atlantic Oscillation (NAO) in the Mediterranean realm Was this modern climate feature active during glacial intervals? YES shifting temperature, wind directions and source of moisture How far west can be tracked ? The Ionian and Adriatic Sea atmospheric circulation
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 2009
Lake Butrint high-resolution window into the last three centuries