Isotopic variability in arctic precipitation as a climatic indicator

Abstract

In this paper, preliminary data are examined from a project studying the variability in the isotopic composition of precipitation across northern Canada and the implications for paleoclimatic reconstruction. The data set shows a geographic variability of about 6 across the Canadian Arctic, roughly double the temporal variability seen in the ice core records from the last 10 000 years. The seasonal variability in d18O values from the Arctic stations in 1991 was as much as 26. A snow and firn core collected on Bylot Island, from the same time period, had a range of 14.8, indicating that processes such as vapor movement, molecular diffusion, and sampling strategy influence the range in d18O values measured in an ice core.

The results discussed indicate that a much better understanding of the geographic and seasonal variation in the d18O values of precipitation is required before a direct linkage between the isotope records in ice cores and global climate change can be determined. Using recently developed radiocarbon dating techniques, buried glacier ice that has been preserved in permafrost may be able to provide the greater spatial and temporal resolution required.