Session 7: Tibetan Plateau: disentangling the Asian monsoon system
Convenors: Peter Frenzel (FSU Jena, Germany), Steffen Mischke (University of Potsdam, Germany), Antje Schwalb (TU Braunschweig, Germany), Liping Zhu (ITP-CAS Beijing, China)
The Tibetan Plateau (TP) influences the Asian monsoon system and is of particular importance for the atmospheric circulation and thus for the global hydrological and energy cycles. Currently, the TP faces a temperature rise of up to 0.3°C per decade, approximately three times the global warming rate. Temperature rise has led to a retreat of 82% of the glaciers on the TP and a degradation of 10% of its permafrost. Consequently, an increase in lake levels due to glacial melting and increased precipitation is being observed during the past five years, after a decline in levels of high-altitude lakes for over two decades. Thus, climate and environments are rapidly changing on the TP and significantly altering the water supply of a major part of Asia.
We welcome papers and posters that contribute to disentangling the impact of the different air masses controlling the spatial distribution of precipitation on the TP through time and their effect on landscape and aquatic ecosystems since the Late Neogene. Suggested topics include:
- New deep geological time records of climate change over the TP
- New quantitative proxy techniques applied to TP lake sediments
- Regional expression of climate change from proxy data-climate modeling comparisons
- Past, modern and future lake level fluctuations
- Human impact
- Atmospheric pollution
Keynote: Professor Steve Colman
University of Minnesota Duluth, USA
S07-KN Records of past climate from the Lake Qinghai Drilling Project and implications for paleoenvironments on the Tibetan Plateau
The Lake Qinghai Drilling Project has obtained drill and piston cores that provide a detailed record of climate change in the Qinghai Basin over the last 32,000 years. Many different kinds of sedimentary analyses provide proxies of past climate, which are dated by abundant radiocarbon ages. Although detailed interpretations of the climate proxies and age models are complex, the results indicate that the climate on the eastern Tibetan Plateau is controlled by two systems: relatively cold, dry Westerly winds, similar to modern winter conditions, and relatively warm, moist circulation, similar to the modern Asian summer monsoon. These two systems clearly are anti-phased in their strength. Cool, Westerlies-dominated climate persisted through late marine isotope stage 3, the last glacial maximum, and the late glacial. Wet conditions dominated in the early Holocene, gradually waning through the rest of the Holocene. Our core-based reconstructions are somewhat at odds with recent dating of shoreline deposits above present lake level.
Isotope stage 3, a time of intermediate climate on long timescales, remains an enigma, apparently an arid extreme in the Qinghai basin, in contrast to suggestions of extreme high lake levels in other parts of the Plateau. Monsoon indicators in the Lake Qinghai record correlate quite well with those in lowland China speleothems. However, in details such as relative variability and abruptness of changes, the Qinghai monsoon record exhibits threshold behavior in the system, in which a major threshold was crossed about 11.5 ka, at the transition from the Younger Dryas to the Holocene.
List of oral presentations:
- S07-01 Xingqi Liu Orbital- and sub-orbital-scale climatic changes of Qaidam Basin in NW China over the past 50,000 years
- S07-02 Mingrui Qiang Multi-proxy analyses of sequential sediments from Genggahai Lake in northeastern Qinghai-Tibetan Plateau: implications for changes in atmospheric circulation
- S07-03 Liping Zhu Last glacial maximum to post glacial climatic transition from a lake core evidence in the central Tibetan Plateau
- S07-04 Andrew Henderson Late glacial high-resolution palaeohydrological changes over southern Tibet: multi-proxy evidence for Indian monsoon variability
- S07-P-01 Anja Schwarz Multi-Proxy climate reconstruction from Central Asian lake sediments
- S07-P-02 Antje Schwalb Carbonate isotope evidence for melt water and dry events during the past 26 kyr on the southern Tibetan Plateau
- S07-P-03 Gerhard Daut Modern sedimentation processes on lake Nam Co, Tibetan Plateau, China – Project presentation and first results.
- S07-P-04 Jianting Ju Hydrodynamic process of Tibetan Plateau lake revealed by grain size: Case study of Lake Pumayum Co
- S07-P-05 Junbo Wang First and preliminary investigations on bathymetry, water quality and modern sedimentation rate of Mapam Yumco and La’ang Co in southern Tibet
- S07-P-06 Nicole Börner Trace elements of ostracod shells from Southern Tibetan Plateau lakes as paleoenvironmental proxy – a methodological intercomparison
- S07-P-07 Peter Frenzel Ostracod-based water depth estimation for Holocene lake sediments of the Tibetan Plateau – a critical review
- S07-P-08 Peter Frenzel Quaternary stromatolites at Tangra Yumco, central Tibetan Plateau
- S07-P-09 Steffen Mischke The present lake reservoir effect of high-altitude lakes in Central Asia
- S07-P-10 Ulrike Herzschuh Quantification of lake nutrient changes using elemental (C, N, S) and isotopic (δ13C and δ15N) composition of submerged plant macrofossils
- S07-P-11 Xiangtong Huang A fluctuating humid climate during the early to middle Holocene in central Asia as indicated by sedimentary and geochemical multi-proxies from Son Kul, Kyrgyzstan
- S07-P-12 Yongbo Wang Quantitative reassessment of Holocene vegetation change on the upper Tibetan Plateau using the pollen-based REVEALS model