NOAA/WDS Paleoclimatology - Sauchyn - Siffleur Ridge - PIFL - ITRDB CANA328

In this paper the mean water year (October through September) flow of the North Saskatchewan River (NSR) at Edmonton, Alberta is reconstructed back to 1063 A.D. using a new network of moisture-sensitive tree-ring chronologies from limber pine and Douglas fir at seven sites in the headwater sub-basins of the North Saskatchewan River Basin (NSRB). Over the full extent of the proxy hydrometric record (1063-2007), we examined 1) the duration and severity of low flow, 2) the dominant frequencies of periodic variability and 3) the correlation between these significant periodicities in proxy streamflow and climate indices, specifically sea surface temperature oscillations, which are known drivers of regional hydroclimatic variability. This new record of the paleohydrology of the NSRB is compared to previous tree-ring reconstructions of the annul flow of the North and South Saskatchewan Rivers. Extending the reference hydrology for the basin from decades to centuries changes perceptions of the reliability of the water supply and understanding of the hydroclimatic variability. The gauge record not does represent the full extent of interannual to multidecadal variability in the tree-ring data; there are periods of low flow in the pre-instrumental record that are longer and more severe than those recorded by the gauge.

本研究针对加拿大阿尔伯塔省埃德蒙顿段北萨斯喀彻温河（North Saskatchewan River, NSR）的平均水文年（10月至次年9月）径流量，利用北萨斯喀彻温河盆地（North Saskatchewan River Basin, NSRB）上游子流域7个站点的柔松（limber pine）与花旗松（Douglas fir）所构建的水分敏感型树轮年表新网络，将径流序列重建至公元1063年。
在1063-2007年的完整代理水文记录序列中，我们开展了三项分析：1）枯水事件的持续时长与严重程度；2）周期变异性的主导频率；3）代理径流序列中的显著周期与气候指数（尤其是已知为区域水文气候变异性驱动因子的海表温度振荡）之间的相关性。
本研究将北萨斯喀彻温河盆地古水文学（paleohydrology）的这一新记录，与此前针对北、南萨斯喀彻温河年径流量的树轮重建结果进行对比。
将该流域的参考水文序列从十年尺度延伸至百年尺度，改变了学界对供水可靠性的认知，以及对区域水文气候变异性的理解。
器测流量记录无法完全覆盖树轮数据所揭示的年际至年代际尺度变异性；在仪器观测前的历史记录中，存在比器测记录更长、更严重的枯水时段。