| Ice cores at Siple Dome, West Antarctic receive the majority of their precipitation from Pacific Ocean moisture sources. Pacific climate patterns, particularly the El Nino- Southern Oscillation, affect the local temperature, atmospheric circulation, and snow accumulation at Siple Dome, as well as isotopic signals (deltaD, delta18O, and deuterium excess). We examined isotopes, accumulation and borehole temperatures from a number of shallow ice cores distributed 60km across the Dome. The data reveal a strong microclimate around Siple Dome heavily influenced by South Pacific climate and the location of the Amundsen Sea low pressure area. The Dome responds to an increase in La Nina conditions by warming, increasing isotope ratios, and increased snowfall. This pattern has bearing on the signal of El Nino throughout the Holocene seen in West Antarctic ice cores, and may explain part of the observed strong divergence of deltaD and delta 18O over the last 10,000 years between sites on opposite sides of the Ross Ice Shelf. |
