修改了天然冰川冰的粘性流动定律:从实验室扩展到冰盖
Meghana Ranganathan1,2, Brent Minchew1
1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge 02139, MA.
概括
以前没有假设的脱位爬行,主导着南极冰盖流动. 这一发现影响了对冰盖不稳定性和未来海平面上升的理解.
科学领域:
- 冰川学的冰川学
- 固体地球物理 固体地球物理
- 气候科学 气候科学
背景情况:
- 冰川流动是海平面变化的关键驱动力,由冰的粘性变形控制.
- 导致冰川规模变形的特定分子机制尚不完全理解.
- 现有的模型往往缺乏实验室发现和大规模冰川动态之间的桥梁.
研究的目的:
- 开发一个统一的冰变形模型,跨越实验室和冰川尺度.
- 建立一个框架,将实验室衍生的流量规律整合到冰川流量模型中.
- 为了绘制南极冰盖中占主导地位的冰变形机制.
主要方法:
- 开发了一种新的冰变形模型.
- 统一现有的粘度参数估计.
- 将实验室衍生的流量规律集成到冰川流动模拟中.
- 从观测数据中估计变形参数.
主要成果:
- 在南极冰盖中形成了占主导地位的冰变形机制的全面地图.
- 在快速流动的地区,被确定失位爬行是主要的机制.
- 发现脱位爬行的应力指数明显高于以前的假设.
结论:
- 与先前的假设相反,脱位爬行是快速流动的南极冰川中占主导地位的机制.
- 对冰的变形的修订理解影响了对海洋冰盖稳定性的预测.
- 更新的流量规律改变了气候条件,可能导致海平面迅速上升.
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