Universidad Complutense de Madrid, 28040 Madrid, Spain.
Proc Natl Acad Sci U S A. 2013 Oct 8;110(41):16350-4. doi: 10.1073/pnas.1306622110. Epub 2013 Sep 23.
Proxy data reveal the existence of episodes of increased deposition of ice-rafted detritus in the North Atlantic Ocean during the last glacial period interpreted as massive iceberg discharges from the Laurentide Ice Sheet. Although these have long been attributed to self-sustained ice sheet oscillations, growing evidence of the crucial role that the ocean plays both for past and future behavior of the cryosphere suggests a climatic control of these ice surges. Here, we present simulations of the last glacial period carried out with a hybrid ice sheet-ice shelf model forced by an oceanic warming index derived from proxy data that accounts for the impact of past ocean circulation changes on ocean temperatures. The model generates a time series of iceberg discharge that closely agrees with ice-rafted debris records over the past 80 ka, indicating that oceanic circulation variations were responsible for the enigmatic ice purges of the last ice age.
代理数据显示，在上一个冰河时期，北大西洋曾出现过多次冰筏碎屑沉积增加的情况，这些情况被解释为来自劳伦太德冰盖的大规模冰山排放。尽管这些情况长期以来一直归因于冰盖的自我维持振荡，但越来越多的证据表明海洋在过去和未来的冰冻圈行为中起着至关重要的作用，这表明这些冰浪是受气候控制的。在这里，我们展示了使用混合冰盖-冰架模型进行的末次冰期模拟，该模型由一个从代理数据中得出的海洋变暖指数驱动，该指数考虑了过去海洋环流变化对海洋温度的影响。该模型生成的冰山排放时间序列与过去 80 千年来的冰筏碎屑记录非常吻合，这表明海洋环流变化是导致上一个冰河时代神秘冰暴的原因。
