Inferring precipitation-anomaly gradients from tree rings
Inferring precipitation-anomaly gradients from tree rings
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DOI：
10.1016/j.quaint.2010.09.006
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发表时间：
2011-04
影响因子：
2.2
通讯作者：
D. Meko;D. Stahle;D. Griffin;T. Knight
中科院分区：
文献类型：
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作者：
D. Meko;D. Stahle;D. Griffin;T. Knight
数十至数百公里降水异常梯度的长期信息对于水文气候学非常重要，有助于更好地了解水分输送系统和径流的时空变化。对美国加利福尼亚州中央山谷 36 个道格拉斯栎树轮站点的冷季（11 月至 4 月）降水进行以站点为中心的重建，进行区域化和评估，以跟踪降水异常的南北梯度。赛事系列是针对 1557 年至 2001 年整体湿润 (W)、整体干燥 (D)、湿润偏北 (W/D) 和湿润偏南 (D/W) 条件而构建的。该事件系列的有趣特征是 1780 年至 1790 年代的 W 事件聚集以及 1816 年至 1818 年连续三年的 D/W 事件（恰巧在 1815 年坦博拉火山喷发之后）。最近 25 年的事件系列的特点是 W 和 D 事件频率较高，而与降水异常强梯度相关的事件频率较低。这一时期最强的五场W赛事以及自1934年以来的九场W赛事中的七场与厄尔尼诺年相匹配。事件系列的最近变化可能是 1976 年后北太平洋大气-海洋气候系统变化的中央山谷足迹。类似的研究可能在其他有对降水足够敏感的树木年轮数据网络的地理区域中证明是有用的。
Long-term information on gradients in precipitation-anomaly over tens to hundreds of km is important to hydroclimatology for improved understanding of the spatiotemporal variability of moisture-delivery systems and runoff. Site-centered reconstructions of cool-season (Nov–Apr) precipitation at 36 Quercus douglasii tree-ring sites in the Central Valley of California, USA, are generated, regionalized, and evaluated for ability to track north–south gradients in precipitation-anomaly. Event series are constructed for overall-wet (W), overall-dry (D), wetter-to-north (W/D) and wetter-to-south (D/W) conditions, 1557–2001. Interesting features of the event series are clustering of W events in the 1780–1790s and a three-year run of D/W events in 1816–1818 (coincidentally following the eruption of Tambora in 1815). The most recent 25 years of the event series stand out for a high frequency of W and D events and low frequency of events associated with strong gradients in precipitation-anomaly. The five strongest W events in this period and seven of the nine W events since 1934 match El Niño years. Recent changes in the event series may be a Central-Valley footprint of a well-documented post-1976 change in the atmosphere-ocean climate system over the North Pacific. Similar studies may prove useful in other geographical areas where networks of tree-ring data sufficiently sensitive to precipitation are available.