Vladimir B. Aizen

Oxygen isotopic and soluble ionic composition of a shallow firn core, Inilchek glacier, central Tien Shan

Oxygen isotopic and soluble ionic measurements made on snow-pit (2 m depth) and firn-core (12.4 m depth) samples recovered from the accumulation zone (5100 m) of Inilchek glacier (43° N, 79° E) provide information on recent (1992-98) climatic and environmental conditions in the central Tien Shan region of central Asia. The combined 14.4 m snow-pit/firn-core profile lies within the firn zone, and contains only one observed melt feature (10 m temperature = -12°C). Although some post-depositional attenuation of the sub-seasonal δ 18 O record is possible, annual cycles are apparent throughout the isotope profile. We therefore use the preserved δ 18 O record to establish a depth/age scale for the core. Mean δ 18 O values for the entire core and for summer periods are consistent with δ 18 /temperature observations, and suggest the δ 18 O record provides a means to reconstruct past changes in summer surface temperature at the site. Major-ion (Na + , K + , Mg 2+ , Ca 2+ , NH 4 + , Cl - , NO 3 - , SO 4 2- ) data from the core demonstrate the dominant influence of dust deposition on the soluble chemistry at the site, and indicate significant interannual variability in atmospheric-dust loading during the 1990s. Anthropogenic impacts on NH 4 + concentrations are observed at the site, and suggest a summer increase in atmospheric NH 4 + that may be related to regional agricultural (nitrogen-rich fertilizer use) activities.

Paleoclimate and Glaciological Reconstruction in Central Asia Through The Collection and Analysis of Ice Cores and Instrumental Data From the Tien Shan

Paleoclimate and Glaciological Reconstruction in Central Asis Through The Collection And Analysis of Ice Cores and Instrumental Data From The Tien Shan