Meteorological processes controlling the variability of net annual accumulation over the Greenland ice sheet

Climatic information available from the spatially extensive suite of fern and ice cores collected under the Program for Arctic and Regional Climate Assessment (PARCA), in conjunction with other data, provides an unparalleled opportunity to investigate accumulation changes over the Greenland ice sheet and to assess its ability to record and preserve a history of North Atlantic climate variability. The ice core derived accumulation histories demonstrate that the influence of glaciological noise on the climate signal is strongly influenced by the accumulation rate. Thus, it may be difficult to discern regionally representative climate signals from individual cores at lower accumulation sites on short time scales suggesting that either time or spatial averaging of the records is necessary.; Individual rotated principal components analysis (RPCA) on the time series of net annual accumulation, the total concentration of insoluble dust particles, and the delta18O annual average and seasonal extrema reveal that cores located in different regions of the ice sheet do not vary consistently for the period of record in this study (1965--1996). Specifically, cores from southern Greenland vary in a manner different from those in the central west region. Thus, proxy climate histories drawn from a single core record are not necessarily representative of the entire ice sheet.; Comparison of the scores associated with the central west and southern Greenland spatial patterns with atmospheric and oceanic data suggest that different processes may be responsible for delivery of precipitation to each region. Correlations of the North Atlantic Oscillation with the core data, combined with composites of mean sea level pressure and 500 hPA heights for accumulation extremes, suggest a negative relationship with the central west region during winter, spring, and summer. Conversely, the same analyses for the southern region suggest a positive relationship to the NAO during summer. Accumulation in the central west region is likely influenced by the NAO during winter and spring, as well as by associated changes in surface temperatures over Canada and sea surface temperatures in the Baffin Bay/Davis Strait. Alternatively, accumulation in southern Greenland is consistently associated with changes in the Pacific.