Data from the South Pole ice core (SPC14) are used to constrain climate; conditions and ice-flow-induced layer thinning for the last 54,000; years. Empirical constraints are obtained from the SPC14 ice and gas; timescales, used to calculate annual-layer thickness and the gas-ice age; difference (Δage), and from high-resolution measurements of water; isotopes, used to calculate the water-isotope diffusion length. Both; Δage and diffusion length depend on firn properties and therefore; contain information about past temperature and snow-accumulation rate. A; statistical inverse approach is used to obtain an ensemble of; reconstructions of temperature, accumulation-rate, and thinning of; annual layers in the ice sheet at the SPC14 site. The traditional; water-isotope/temperature relationship is not used as a constraint; the; results therefore provide an independent calibration of that; relationship. The temperature reconstruction yields a; glacial-interglacial temperature change of 6.7 ± 1.0 °C at the South; Pole. The sensitivity of δ180 to temperature is 0.99 ± 0.03 ‰/°C,; significantly greater than the spatial slope of ~0.8; ‰/°C that has been used previously to determine temperature changes from; East Antarctic ice core records. The reconstructions of accumulation; rate and ice thinning show millennial-scale variations in the thinning; function as well as decreased thinning at depth compared to the results; of a 1-D ice flow model, suggesting influence of bedrock topography on; ice flow.
