A Holocene record of Pacific Decadal Oscillation (PDO)-related hydrologic variability in Southern California (Lake Elsinore, CA)
A Holocene record of Pacific Decadal Oscillation (PDO)-related hydrologic variability in Southern California (Lake Elsinore, CA)
复制标题
DOI：
10.1007/s10933-010-9454-0
复制
发表时间：
2010-07
影响因子：
2.1
通讯作者：
M. Kirby;S. Lund;W. Patterson;M. A. Anderson;B. Bird;L. Ivanovici;P. Monarrez;S. Nielsen
中科院分区：
文献类型：
--
作者：
M. Kirby;S. Lund;W. Patterson;M. A. Anderson;B. Bird;L. Ivanovici;P. Monarrez;S. Nielsen
南加州全新世气候的高分辨率陆地记录很少。此外，没有关于太平洋年代际振荡 (PDO) 变化的记录，太平洋年代际涛动 (PDO) 变化是该地区十年至多个年代际气候变化的主要驱动因素，已有 1,000 多年的历史。然而，最近对埃尔西诺湖的研究表明，该湖的沉积物具有古环境分析和重建的巨大潜力。新的 1 厘米连续粒度数据揭示了南加州全新世气候历史比之前在该地点认识到的更为复杂。对 20 世纪 PDO 指数、湖泊水位变化、圣哈辛托河流量和沙子百分比的现代比较表明，沙子含量是数十年到百年以及事件（即风暴）时间尺度上与 PDO 相关的水文变化的合理定性指标。提出了沉积模型来解释砂水文代理。沙土水文代理数据揭示了整个全新世九个百年尺度的湿润和干燥气候间隔。总沙子值百分比高于 150-9,700 校准年 BP 平均值 >1.5 个标准差的情况在 9,700 至 3,200 校准年 BP 之间很常见 (n= 41)，但在 3,200 至 150 校准年 BP 之间则很少见 (n= 6)。这种差异被解释为异常潮湿（高流量）年份的频率变化和/或大型风暴活动的变化。与其他区域水文代理（10 个站点）的比较显示，整个区域偶尔有相似之处（即 9 个埃尔西诺潮湿区间中的 6 个出现在 > 50% 的比较站点中）。然而，只有全新世早期和小冰期间隔在整个地区被一致地解释为均匀湿润（≥80%的比较地点）。与两次 ENSO 重建数据的比较表明，与埃尔西诺数据几乎没有相关性（如果有的话），这表明 ENSO 变化并不是南加州全新世气候的主要强迫。
High-resolution terrestrial records of Holocene climate from Southern California are scarce. Moreover, there are no records of Pacific Decadal Oscillation (PDO) variability, a major driver of decadal to multi-decadal climate variability for the region, older than 1,000 years. Recent research on Lake Elsinore, however, has shown that the lake’s sediments hold excellent potential for paleoenvironmental analysis and reconstruction. New 1-cm contiguous grain size data reveal a more complex Holocene climate history for Southern California than previously recognized at the site. A modern comparison between the twentieth century PDO index, lake level change, San Jacinto River discharge, and percent sand suggests that sand content is a reasonable, qualitative proxy for PDO-related, hydrologic variability at both multi-decadal-to-centennial as well as event (i.e. storm) timescales. A depositional model is proposed to explain the sand-hydrologic proxy. The sand-hydrologic proxy data reveal nine centennial-scale intervals of wet and dry climate throughout the Holocene. Percent total sand values >1.5 standard deviation above the 150–9,700 cal year BP average are frequent between 9,700 and 3,200 cal year BP (n= 41), but they are rare from 3,200 to 150 cal year BP (n= 6). This disparity is interpreted as a change in the frequency of exceptionally wet (high discharge) years and/or changes in large storm activity. A comparison to other regional hydrologic proxies (10 sites) shows more then occasional similarities across the region (i.e. 6 of 9 Elsinore wet intervals are present at >50% of the comparison sites). Only the early Holocene and the Little Ice Age intervals, however, are interpreted consistently across the region as uniformly wet (≥80% of the comparison sites). A comparison to two ENSO reconstructions indicates little, if any, correlation to the Elsinore data, suggesting that ENSO variability is not the predominant forcing of Holocene climate in Southern California.