Wendt Kathleen A, Dublyansky Yuri V, Moseley Gina E, Edwards R Lawrence, Cheng Hai, Spötl Christoph
Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria.
Department of Earth Sciences, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455, USA.
Sci Adv. 2018 Oct 24;4(10):eaau1375. doi: 10.1126/sciadv.aau1375. eCollection 2018 Oct.
The projected long-term drying of the southwest (SW) United States in response to climate warming raises a sobering alarm for this already water-limited region, yet the climatic controls on moisture availability over longer time scales remain a topic of debate. Here, we present a 350,000-year record of past water table fluctuations in Devils Hole 2 cave that are driven by variations in recharge amount to the local groundwater flow system. Because of the unprecedented length and precision of our record, we can observe variations in regional moisture availability over the last three glacial-interglacial cycles at a millennial-scale resolution. The timing of past water table rises and falls (>9 m in amplitude) closely coincides with the expansion and reduction of Northern Hemisphere ice volume, which in turn influences the position and intensity of westerly winter storms on orbital time scales. Superimposed on this long-term trend are millennial-scale highstands recorded during the last glaciation that coincide with North Atlantic Heinrich events. Earlier millennial-scale highstands provide the first evidence of multiple short-lived wet periods in the SW United States linked to coeval cooling intervals in the North Atlantic during marine isotope stages 6 and 8. The Devils Hole 2 water table record is currently the longest independently dated paleomoisture record in the SW United States and thus provides a critical testbed to examine the controls on regional moisture availability over larger time scales.
预计美国西南部（SW）因气候变暖而出现的长期干旱，给这个本就水资源有限的地区敲响了警钟，然而，在更长时间尺度上，对水分可利用性的气候控制仍是一个有争议的话题。在此，我们展示了一份35万年的魔鬼洞2号洞穴过去地下水位波动记录，这些波动是由当地地下水流系统补给量的变化驱动的。由于我们记录的长度和精度前所未有的，我们能够以千年尺度分辨率观察过去三个冰期 - 间冰期循环中区域水分可利用性的变化。过去地下水位上升和下降（幅度>9米）的时间与北半球冰量的增减密切吻合，而这反过来又在轨道时间尺度上影响冬季西风风暴的位置和强度。叠加在这一长期趋势之上的是末次冰期记录的千年尺度高水位，与北大西洋 Heinrich 事件相吻合。早期的千年尺度高水位首次证明了美国西南部多次短暂湿润期与海洋同位素阶段6和8期间北大西洋同期的冷却间隔有关。魔鬼洞2号地下水位记录目前是美国西南部最长的独立测年的古湿度记录，因此为检验更大时间尺度上区域水分可利用性的控制因素提供了一个关键的试验台。
