Pollen-inferred vegetation and environmental changes in the central Tibetan Plateau since 8200 yr BP  

作　　者：LIU Kam-Biu Carrie MORRILL Jonathan T. OVERPECK Julia E. COLE 

机构地区：[1]Department of Oceanography and Coastal Sciences, School of the Coast and Environment, Louisiana State University [2]NOAA Paleoclimatology Program and Cooperative Institute for Research in Environmental Sciences (CIRES) [3]Institute for the Study of Planet Earth and Department of Geosciences, University of Arizona

出　　处：《Science China Earth Sciences》2009年第8期1104-1114,共11页中国科学（地球科学英文版）

基　　金：Supported by Chinese Academy of Sciences 100 Talents Project (Grant No. 29082762);National Natural Science Foundation of China (Grant Nos. 40671196, 40372085, 49371068, 49871078);U.S. National Science Foundation (Grant Nos. ATM-9410491, ATM-008194)

摘　　要：The ecotone between alpine steppe and meadow in the central Tibetan Plateau is sensitive to climate changes. Here we used the pollen records from three lakes in this region to reconstruct the evolution of local vegetation and climate since 8200 cal. yr BP. The history of temperature and precipitation was reconstructed quantitatively with multi-bioclimatic indexes and a transfer function from pollen records. Results show that the steppe/meadow dominated during the period of 8200―6500 cal. yr BP, especially 8200―7200 cal. yr BP, indicating the central Tibetan Plateau was controlled by strong monsoon. The steppe dominated during the periods of 6000―4900, 4400―3900, and 2800―2400 cal. yr BP. The steppe decreased gradually and the meadow expanded during the period of 4900―4400 cal. yr BP. Three century-scale drought events occurred during 5800―4900, 4400―3900 and 2800 cal. yr BP, respectively. The first time when the regional climate shifted to the present level was at 6500 cal. yr BP in the central Plateau. Since 3000 cal. yr BP, the temperature and precipitation have decreased gradually to the present level. However, the cold climate between 700―300 cal. yr BP likely corresponds to the Little Ice Age.The ecotone between alpine steppe and meadow in the central Tibetan Plateau is sensitive to climate changes. Here we used the pollen records from three lakes in this region to reconstruct the evolution of local vegetation and climate since 8200 cal. yr BP. The history of temperature and precipitation was reconstructed quantitatively with multi-bioclimatic indexes and a transfer function from pollen records. Results show that the steppe/meadow dominated during the period of 8200–6500 cal. yr BP, especially 8200–7200 cal. yr BP, indicating the central Tibetan Plateau was controlled by strong monsoon. The steppe dominated during the periods of 6000–4900, 4400–3900, and 2800–2400 cal. yr BP. The steppe decreased gradually and the meadow expanded during the period of 4900–4400 cal. yr BP. Three century-scale drought events occurred during 5800–4900, 4400–3900 and 2800 cal. yr BP, respectively. The first time when the regional climate shifted to the present level was at 6500 cal. yr BP in the central Plateau. Since 3000 cal. yr BP, the temperature and precipitation have decreased gradually to the present level. However, the cold climate between 700–300 cal. yr BP likely corresponds to the Little Ice Age.

关 键 词：the meadow-steppe ECOTONE (MSE) POLLEN record bioclimatic index central Tibetan Plateau 

分 类 号：P467[天文地球—大气科学及气象学]