Decadal timescale links between Antarctic Peninsula ice-core oxygen-18, deuterium and temperature

Abstract

The Antarctic Peninsula region has exprienced a long-term warming trend over the twentieth century, with the 1971-90 mean at Faraday being 1.9°C warmer than the mean over 1903-41 based on expedition reports. For the period prior to 1900, there is conflicting evidence from different data sources. An initial interpretation of isotopic data from ice cores suggests that the nineteenth century was warmer than the twentieth century. In contrast, snow accumulation rate data for the nineteenth century from the same ice cores suggest lower temperatures. Here we investigate these facts by studying the links between atmospheric temperature over the Antarctic Peninsula, circulation parameters and isotopic data over the period of instrumental records. We show that the relationships between these variables are complex and highly spatially variable. In particular, the correlations between temperature and δ 18O and δD are generally of the order r = 0.5 or less on timescales of one to five years. Conflicts between evidence from accumulation rate and isotopic data appear to reflect the influence of source-region effects on the isotope records. To unravel the complex isotopic records available for the Peninsula region better; additional cores must be analysed for both δ 18O and 8D at the same site.