Collaborative Research: Geophysical Study of Ice Stream Stick-slip Dynamics

合作研究：冰流粘滑动力学地球物理研究

• 批准号: 0944286
• 负责人: Sridhar Anandakrishnan
• 金额: $ 18.16万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944286&HistoricalAwards=false
• 关键词: Collaborative; Research; Geophysical; Study; Ice

Winberry/0944794This award supports a three-year study of the ongoing deceleration and stick-slip motion of Whillans Ice Stream (WIS), West Antarctica. Understanding the dynamic behavior of ice streams is essential for predicting the future of the West Antarctic Ice Sheet (WAIS). Despite being one of the best-studied ice streams in Antarctica, the surprising flow characteristics of WIS continue to demand interdisciplinary research. Recent estimates indicate that the WIS may stagnate within 50 years, resulting in a significant change to the mass balance of the Siple Coast sector of West Antarctica. The reasons for the ongoing stagnation are not well known, and are possibly linked (causally or coincidentally) to the stick-slip behavior. Our recent work on WIS stick-slip motion suggest that all slip events nucleate from a common location on the ice stream, suggesting that a relatively small (approximately 10 km in diameter) region of the exerts fundamental control over the flow of this large ice stream (100s of km long and 100 kilometers wide). We hypothesize that this is a region of increased bed strength and our measurements will address that hypothesis. We will deploy a series of GPS receivers and seismometers on the ice stream to accurately locate the nucleation region so that a comprehensive ground based geophysical survey can be conducted to determine the physical properties of bed at the nucleation point. The ground geophysical program will consist of reflection seismic and ice-penetrating radar studies that will better constrain the properties of both the hypothesized higher-friction nucleation zone and the surrounding regions. Slip events also generate seismic energy that can be recorded 100s of km away from the ice stream, thus, the GPS and seismometer deployment will also aid us in relating seismic waveforms directly with the rapid motion that occurs during slip events. The increased ability to relate rupture processes with seismic emissions will allow us to use archived seismic records to explore changes in the behavior of WIS during the later half of the 20th century. Broader impacts of this study include improved knowledge ice sheet dynamics, which remain a poorly constrained component of the climate system, thus, limiting our ability to predict the Earth's response to climate change. The scientific work includes the education of two graduate students and continued training of one post-doctoral scholar, thus helping to train the next generation of polar scientists. We will expose the broader public to polar science through interactions with the media and by take advantaging of programs to include K-12 educators in our field work.

Winberry/0944794这项奖项支持了西南极洲西南极的Whillans Ice Stream（WIS）正在进行的减速和滑滑运动的三年研究。了解冰流的动态行为对于预测南极冰盖（WAIS）的未来至关重要。尽管是南极洲最久经考验的冰流之一，但WIS的令人惊讶的流动特征仍然需要跨学科研究。最近的估计表明，WIS可能在50年内停滞不前，从而导致南极西部沿海部门的质量平衡发生了重大变化。持续停滞的原因尚不清楚，并且可能与棒滑动行为联系在一起（因果或偶然）。我们最近对WIS粘性运动运动的工作表明，所有滑移事件都来自冰流的共同位置成核，这表明对这一大冰流的流动（长度约为100 s km，宽100公里）的基本控制相对较小（直径约10 km）。 我们假设这是一个增加床强度的区域，我们的测量结果将解决该假设。 我们将在冰流上部署一系列的GPS接收器和地震仪，以准确定位成核区域，以便可以进行全面的基于地面的地球物理调查，以确定成核点处的床的物理性质。地球物理计划将包括反射地震和冰根化雷达研究，这些研究将更好地限制假设的高摩擦成核区和周围区域的特性。滑动事件还产生了地震能，可以记录到距冰流100公里的100公里，因此，GPS和地震仪的部署还将有助于我们将地震波形直接与滑动事件中发生的快速运动联系起来。将破裂过程与地震排放相关联的能力增加将使我们能够使用存档的地震记录来探索20世纪后半叶WIS行为的变化。这项研究的更广泛的影响包括改进的知识冰盖动态，这些动态仍然是气候系统中受限制的组成部分，因此限制了我们预测地球对气候变化反应的能力。科学工作包括对两名研究生的教育以及一名博士后学者的继续培训，从而有助于培训下一代的极地科​​学家。我们将通过与媒体的互动，并利用计划将K-12教育者包括在我们的实地工作中，使更广泛的公众成为极地科学。