HR: 14:25h
AN: PP33D-04    [Abstracts]
TI: Ice-core Evidence of Holocene Climatic and Environmental Variations Across Tibet
AU: * Thompson, L G
EM: thompson.3@osu.edu
AF: The Ohio State University Byrd Polar Research Center, 1090 Carmack Road, Columbus, OH 43210, United States
AU: Davis, M E
EM: davis.3@osu.edu
AF: The Ohio State University Byrd Polar Research Center, 1090 Carmack Road, Columbus, OH 43210, United States
AU: Yao, T
EM: tdyao@itpcas.ac.cn
AF: Institute of Tibetan Plateau Research - CAS, No. 18 Shuangqing Road Haidan District, Beijing, 100085, China
AU: Kehrwald, N
EM: kehrwald.1@osu.edu
AF: The Ohio State University Byrd Polar Research Center, 1090 Carmack Road, Columbus, OH 43210, United States
AU: Lin, P
EM: lin.25@osu.edu
AF: The Ohio State University Byrd Polar Research Center, 1090 Carmack Road, Columbus, OH 43210, United States
AB: Since 1984 The Ohio State University, in collaboration with the Lanzhou Institute of Glaciology and Geocryology and more recently the Institute for Tibetan Plateau Research, has recovered ice cores from a number of ice fields across Tibet. The Guliya ice cap is located in the western Kunlun Mountains while the Dasuopu and Naimona`nyi ice fields are located in the Himalayas to the south. The Puruogangri ice cap is in the Tanggula Mountains that are considered a boundary between the monsoon-dominated southern region and the continental-dominated northern region. All these ice core records are complete, except Naimona`nyi, which was drilled in late 2006. Dasuopu has a high annual accumulation rate (~1 meter water equivalent per year, or w.e. a^-1) along with low soluble and insoluble aerosol content and a well-defined seasonal stratigraphy. The Guliya and Puruogangri cores are from more arid regions (0.20 - 0.40 m w.e. a^-1), contain high concentrations of mineral dust and ionic species and a less distinct seasonal stratigraphy. The climate of the Tibetan Plateau also varies from west to east. The Guliya ice cap provided the longest ice core record recovered to date, extending through the last glacial cycle. This likely reflects the dominance of the continental westerlies in northwestern Tibet. On the other hand, the Puruogangri, Dasuopu and Naimona`nyi ice core records appear to be much younger and those ice fields may have formed during the Holocene "Optimum" when Northern Hemisphere insolation was high and forced a more active Indian/Asian monsoon circulation. Climate models indicate that sections of High Asia were much warmer in the early Holocene than in the Late Holocene; thus, it is possible that these glaciers did not exist prior to that time. Regional and local variations in climate will be presented, using a combination of stable isotopes, soluble and insoluble aerosol concentrations, and physical stratigraphy. Special emphasis is placed on the last 2000 years when the dating control is more robust. The Holocene records from Dasuopu, Puruogangri and Guliya reflect regional variations in climate, but also display large-scale similarities over decadal and centennial time scales. For example, although the warming trend of the twentieth century is present in all the records, it is more pronounced in the Himalayan ice cores than in those from the Western Kunlun.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1621 Cryospheric change (0776)
DE: 1630 Impacts of global change (1225)
DE: 1637 Regional climate change
DE: 4932 Ice cores (0724)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting