Spatial and temporal isotopic patterns across the West Antarctic Ice Sheet Divide from new snowpits and firn cores

Studies have shown significant warming through the 1990's in the West Antarctic Ice Sheet (WAIS) divide but the ice core isotopic records used in those studies end in 2000-2001. Fourteen sub-annually resolved snowpits and firn cores were collected during traverses in 2010 and 2011 across the WAIS divide. One of the new cores overlaps in time with a core drilled in 2000 at the same location. These two cores correlate significantly with each other, giving confidence in the utility of the new data. These new isotopic records are combined with existing isotopic data in the region to quantify the spatial and temporal patterns in the isotopes, and extend the previous records through 2011. Significance of these isotopic patterns across WAIS is determined and is used to re-evaluate the warming of the West Antarctic interior over recent decades. The proposed mechanisms for the warming due to regional changes in atmospheric circulation, sea surface temperature, and sea ice will be re-evaluated using these updated isotopic records and new GCM simulations with isotopic tracers.