NOAA/WDS Paleoclimatology - Dronning Maud Land Coastal Ice Core 470 Year Oxygen Isotope Data

The role of Antarctic climate variables within the global system and its spatial and temporal complexity are still poorly understood due to the limited and very short periods of observational data collected over a few decades. In order to reconstruct the coastal Antarctic variability during the past five centuries with annual to sub-annual resolution, two firn/ice cores (62 and 65 m) from the central Dronning Maud Land region were studied for proxy parameters like stable isotope and dust records. While the IND-25/B5 provided high-resolution records of the past 100 years (1905-2005), the IND-22/B4 core represented the past ~470 years (1530-2002) of climate change. The IND-25/B5 delta18O record revealed a significant relation to the Southern Annular Mode (SAM), except during certain intervals (1918-1927, 1938-1947 & 1989-2005), when linkage to the El Niño Southern Oscillation (ENSO) was established through the in-phase relation between SAM and ENSO. However, on a decadal scale, a significant relationship between delta18O and SAM is observed that overrides the intermittent the influence of ENSO. Significant shifts in the deuterium excess record were also observed during periods of ENSO interaction. This may imply a change in moisture source during the periods of stronger ENSO teleconnections. The extended records of IND-22/B4 exhibited relatively more negative delta18O values during periods of reduced solar activity like the Dalton and Maunder Minima, suggesting influence of solar activity on Antarctic climate. The estimated surface air temperatures using the delta18O profiles of two ice cores revealed a significant warming by 0.6-1C per century, with greatly enhanced warming during the past few decades (~0.4C per decade).