Seasonal deuterium excess in a Tien Shan ice core: Influence of moisture transport and recycling in Central Asia

Geophysical Research Letters
By: , and 

Links

Abstract

Stable water isotope (δ18O, δD) data from a high elevation (5100 masl) ice core recovered from the Tien Shan Mountains, Kyrgyzstan, display a seasonal cycle in deuterium excess (d = δD - 8*δ18O) related to changes in the regional hydrologic cycle during 1994-2000. While there is a strong correlation (r2 = 0.98) between δ18O and δD in the ice core samples, the regression slope (6.9) and mean d value (23.0) are significantly different than the global meteoric water line values. The resulting time-series ice core d profile contains distinct winter maxima and summer minima, with a yearly d amplitude of ∼15-20‰. Local-scale processes that may affect d values preserved in the ice core are not consistent with the observed seasonal variability. Data from Central Asian monitoring sites in the Global Network of Isotopes in Precipitation (GNIP) have similar seasonal d changes. We suggest that regional-scale hydrological conditions, including seasonal changes in moisture source, transport, and recycling in the Caspian/Aral Sea region, are responsible for the observed spatial and temporal d variability.

Publication type Article
Publication Subtype Journal Article
Title Seasonal deuterium excess in a Tien Shan ice core: Influence of moisture transport and recycling in Central Asia
Series title Geophysical Research Letters
DOI 10.1029/2003GL017896
Volume 30
Issue 18
Year Published 2003
Language English
Publisher American Geophysical Union
Description 4 p.
Google Analytic Metrics Metrics page
Additional publication details