HR: 0830h
AN: C11B-0807    [PDF]
TI: Snow and ice-core stable isotopes time series and precipitation in Altai Mountains (Siberia)
AU: * Aizen, E M
EM: aizen@bren.ucsb.edu
AF: Elena Aizen, Department of Geography, College of Science, P.O. Box 443025, Moscow, ID 83844-3025 United States
AU: Aizen, V B
EM: aizen@uidaho.edu
AF: Elena Aizen, Department of Geography, College of Science, P.O. Box 443025, Moscow, ID 83844-3025 United States
AU: Fujita, K
EM: bri@ihas.nagoya-u.ac.jp
AF: Koji Fujita, Graduate School of Environmental Studies, Nagoya University c/o Hydrospherc Atmospheric Research Center Chikusa-ku, Nagoya, 464-8601 Japan
AU: Nikitin, S A
EM: nikitin@ic.tsu.ru
AF: Stanislav Nikitin, Department of Geology and Geography, Tomsk State University, 36 Lenina Str., Tomsk, 634050 Russian Federation
AU: Kreutz, K
EM: karl.kreutz@maine.edu
AF: Karl Kreutz, Stable Isotope Laboratory, University of Maine, Orono, 04469 United States
AB: The Altai's glaciers provide information on internal and external hydrological cycles over the Eurasia, storing long-term records of fresh water transport from Atlantic and Pacific Oceans and the Central Asia closed drainage basin. The 22 m firn-ice cores and 3 m snow pits from the Belukha firn Plateau (4109 - 4115 m) were used to recover climatic records through physical and stable isotopes analysis. Well preserved seasonal $\delta$$^{2}$H and $\delta$$^{18}$O signals exist in the snow firn records with the mean of oxygen isotope ratios of -13.6$\permil$. Three distinct data on moisture origin were clustered, i.e., Atlantic, Pacific Oceans and internal central Asian drainage basin. Two thirds of annual accumulation was formed by oceanic precipitation and more than half in annual accumulation has isotopic ratios corresponding to evaporation over the northern Atlantic Ocean. The $\delta$D-$\delta$$^{18}$O relationship associated with Atlantic moisture source varied slightly during the year with intercept range from 8.8 in winter to 12.0 in spring and with almost unchangeable during the year deuterium excess of 10$\permil$. The contribution of precipitation transferred from the Pacific Ocean, which has smallest deuterium excess (4.6$\permil$, comprises on average 16% in annual accumulation with maximum in summer (up to 21%) and minimum of 8% in spring. The low d-excess was associated with the high atmospheric moisture saturation over the ocean during formation of precipitation. The mean and absolute values of $\delta$$^{18}$O for records related to Pacific Ocean origin are the highest among three clusters (-9$\permil$) that associated with highest air temperature during precipitation. The internal moisture source provides the largest portion of precipitation to Altai glaciers in the spring (up to 42%) and the minimum contribution during winter. The linear transfer function between mean air temperature and the isotopic composition in accumulated precipitation originating from the same external or internal moisture source was developed at the seasonal temporal scale.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 1015 Composition of the core
DE: 1040 Isotopic composition/chemistry
DE: 1600 GLOBAL CHANGE (New category)
DE: 1827 Glaciology (1863)
SC: Cryosphere [C]
MN: 2003 Fall Meeting