Laurentide Ice Saddle Mergers Drive Rapid Sea Level Drops During Glaciations
Laurentide Ice Saddle Mergers Drive Rapid Sea Level Drops During Glaciations
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DOI：
10.1029/2021gl094263
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发表时间：
2021-07
影响因子：
5.2
通讯作者：
Weiwen Ji;A. Robel;E. Tziperman;Jun Yang
中科院分区：
文献类型：
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作者：
Weiwen Ji;A. Robel;E. Tziperman;Jun Yang
最近的冰川期包括几个海平面快速下降的时期，但人们对这些时期仍知之甚少。在这里，我们表明，由于两个独立的冰盖合并而没有相应的快速气候强迫，可能会导致海平面快速下降。使用平行冰盖模型（PISM），我们通过逐渐降低平衡线高度（ELA）来模拟劳伦泰德冰盖（LIS）的冰川作用。劳伦泰冰盖延伸的基瓦廷部分与哈德逊湾以南劳伦泰冰盖的拉布拉多部分合并，导致合并区域表面海拔增加和表面质量平衡增加之间的正反馈，导致冰盖快速增长。 LIS 模拟鞍形合并在不到 20 kyr 的时间内使海平面降低 20 m，海平面下降周期超过 2 m/kyr，与古海平面记录中观察到的情况类似。
Recent glacial periods have included several periods of rapid sea level drop that are still not well understood. Here we show that rapid sea level drops can occur due to merger of two separate ice sheets without correspondingly rapid climate forcing. Using the Parallel Ice Sheet Model (PISM), we simulate glaciation of the Laurentide Ice Sheet (LIS) by gradually decreasing equilibrium‐line altitude (ELA). Merger of the extended Keewatin sector of the Laurentide Ice Sheet with Labrador sector of the Laurentide Ice Sheet south of Hudson Bay causes a positive feedback between increasing surface elevation and increasing surface mass balance in the merger region, leading to fast ice sheet growth. The simulated saddle merger of LIS lowers sea level by 20 m in less than 20 kyr with periods of sea level fall exceeding 2 m/kyr, similar to those observed in paleo‐sea level records.