HR: 0800h
AN: C51A-1017    [Abstracts]
TI: Isotope/Air Temperature Relationships From Snow-Firn Core Time Series at the Northern and Southern Periphery of the Central Asian Mountain System
AU: * Joswiak, D
EM: josw4889@uidaho.edu
AF: Dept. of Geography, College of Science, University of Idaho, McClure Hall 203, Moscow, ID 83844-3025 United States
AU: Aizen, E
EM: eaizen@uidaho.edu
AF: Dept. of Geography, College of Science, University of Idaho, McClure Hall 203, Moscow, ID 83844-3025 United States
AU: Aizen, V
EM: aizen@uidaho.edu
AF: Dept. of Geography, College of Science, University of Idaho, McClure Hall 203, Moscow, ID 83844-3025 United States
AB: Spatial variability of stable isotope records from snow pits and snow-firn cores to depths of 21 m are used to examine isotope/air temperature relationships for three locations at the northern and southern periphery of the central Asian mountain system: the West Belukha glaciated Plateau in the Altai, the head of Inylchek Glacier in central Tien Shan, and the Bomi glacierized massif in southeastern Tibet. The $^{18}$O records show pronounced maxima and minima, interpreted to represent annual accumulation layers and verified with stratigraphic profiles. Mean $\delta$$^{18}$O from the Altai core is -13.6\permil, -16.0\permil for the Tien Shan core, and -16.3\permil for the southeastern Tibet core. Mean annual ranges of the $\delta$$^{18}$O signal vary from 9.5\permil in the Altai core, to 16.6\permil in the Tien Shan core, and 10.1\permil in the southeastern Tibet core. Mean deuterium excess varied from 10.9\permil for the Altai core to 23.0\permil for the Tien Shan core. Isotope/air temperature relationships are examined for variability of regression lines (slope and intercept) associated with internal and external moisture sources, which vary seasonally. Positive regression line slopes are observed for the Tien Shan and Altai Mountains, with minimum $\delta$$^{18}$O values associated with minimum winter temperatures. A negative regression line slope is observed at southeastern Tibet, with minimum $\delta$$^{18}$O values associated with heavy amounts of isotopically depleted precipitation occurring during the summer months at this location. These isotope records will aid in providing information important to the forecasting of global climate change linking regional responses with atmospheric circulation patterns from the North Atlantic to Pacific and Indian Oceans. These techniques can be applied to recently recovered deep (surface to bottom) ice cores from the central Tien Shan and Altai Mountains.
DE: 1040 Isotopic composition/chemistry
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting