Thursday, September 10, 2009, 4:30PM - 5:30PM
Siple Dome, West Antarctic ice cores receive the majority of their precipitation from a Pacific Ocean moisture source. Pacific climate patterns, particularly the El Niño-Southern Oscillation, affect the local temperature, atmospheric circulation, and snow accumulation at Siple Dome. Isotopic signals (∂D, ∂18O, and deuterium excess), from seven spatial shallow ice cores reveal an intense micro-climate around Siple Dome heavily influenced by South Pacific climate and the location of the Amundsen Sea Low Pressure Area. At a time when El Nino events have been increasing since the mid-Holocene, Siple Dome itself detects both El Nino and La Nina, but has a bias toward La Nina conditions--a phenomenon contrasted in four deep Antarctic ice cores. Near term increase in ENSO frequency is detected from spectral analysis of a high-resolution Siple Dome ice core dating back 350 years.