Temporal and Spatial Variability in Snow Accumulation at WAIS Divide over Recent Centuries

Temporal and spatial variability in snow accumulation was evaluated using ice cores collected in 2000 (ITASE 00-1) and 2005 (WDC05A, WDC05Q) from the West Antarctic Ice Sheet Divide (WAIS Divide) project site. The ice cores were dated based on annual layer counting of multiple glaciochemical measurements resulting in mean annual accumulation rates of 0.200, 0.204, and 0.221 mweq yr-1 for WDC05A, WDC05Q, and ITASE 00-1, respectively. An analysis of variance of accumulation in the ice core array was used to determine the small scale spatial variability (SSV), allowing for quantification of uncertainty in an individual accumulation record. The spatial variability for the WAIS Divide project site was calculated to be 0.030 mweq yr-1, or approximately 15% of the average annual accumulation. An accumulation record representative of the WAIS Divide local area over recent centuries was developed using a principal component analysis of the array to identify the coherent accumulation signal. The WAIS Divide local area accumulation record did not exhibit a trend over recent centuries, with 14% inter-annual variability (1-standard deviation of the mean) and SSV of 0.017 mweq yr-1. Correlations between the WAIS Divide local accumulation record and atmospheric indices (e.g., Antarctic Oscillation and El-Nino Southern Oscillation) exhibited periods when the records oscillate in and out of phase. Thus, identifying relationships between WAIS Divide accumulation records and geophysical processes over recent centuries may be problematic.