Climate variability in the Aral Sea basin (Central Asia) during the late Holocene based on vegetation changes

• Published in: Quaternary Research
• Main Authors: Sorrel, Philippe, Popescu, Speranta-Maria, Klotz, Stefan, Suc, Jean-Pierre, Oberhänsli, Hedi
• Other Authors: GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ), PaleoEnvironnements et PaleobioSphere (PEPS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut für Geowissenschaften, Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: Pollen analysis; Vegetation; Climate; Aral Sea; Late Holocene; Central Asia; Negative NAO; [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.science/hal-00172305; https://doi.org/10.1016/j.yqres.2006.11.006

International audience High-resolution pollen analyses (~50 yr) from sediment cores retrieved at Chernyshov Bay in the NW Large Aral Sea record shifts in vegetational development from subdesertic to steppe vegetation in the Aral Sea basin during the late Holocene. Using pollen data to quantify climatic parameters, we reconstruct and date for the first time significant changes in moisture conditions in Central Asia during the past 2000 yr. Cold and arid conditions prevailed between ca. AD 0 and 400, AD 900 and 1150, and AD 1500 and 1650 with the extension of xeric vegetation dominated by steppe elements. These intervals are characterized by low winter and summer mean temperatures and low mean annual precipitation (Pmm <250 mm/yr). Conversely, the most suitable climate conditions occurred between ca. AD 400 and 900, and AD 1150 and 1450, when steppe vegetation was enriched by plants requiring moister conditions (Pmm ~250–500 mm/yr) and some trees developed. Our results are fairly consistent with other late Holocene records from the eastern Mediterranean region and the Middle East, showing that regional rainfall in Central Asia is predominantly controlled by the eastern Mediterranean cyclonic system when the North Atlantic Oscillation (NAO) is in a negative phase.