NOAA/WDS Paleoclimatology - Dronning Maud Land Coastal Ice Core 100 Year Subannual dD and d18O Data

Stable isotope records of oxygen and hydrogen were studied from a 65 m long ice core retrieved from central Dronning Maud Land, East Antarctica, in order to reconstruct the coastal Antarctic climate variability during the last century and its relation to the Southern Annular Mode (SAM) and El Niño-Southern Oscillation (ENSO). The d18O records showed a significant relation to the SAM with a dominant ~4 years variability, except during specific periods (1918-1927, 1938-1947, and 1989-2005) when ENSO teleconnection was established through the in-phase relation between SAM and Southern Oscillation Index (SOI). The combined influence of ENSO and SAM was seen on surface air temperatures in this region mainly during the austral summer season from 1989 to 2005. Further, a significant relationship between d18O and SAM was observed on a decadal scale, which overrides the intermittent influence of ENSO. Major shifts in the deuterium excess record were observed during periods of ENSO teleconnections, which support a shift in moisture source regions during the periods of stronger ENSO teleconnections. Surface air temperatures estimated using the d18O-T spatial slope for this region depicted a significant warming of 1C for the past century. The study reveals that throughout the last century, SAM was the dominant mode of climatic variability in the coastal region of central Dronning Maud Land on a decadal scale.