| 项目编号: | 1443525
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| 项目名称: | High Resolution Heterogeneity at the Base of Whillans Ice Stream and its Control on Ice Dynamics |
| 作者: | Susan Schwartz
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| 承担单位: | University of California-Santa Cruz
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| 批准年: | 2014
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| 开始日期: | 2015-09-01
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| 结束日期: | 2018-08-31
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| 资助金额: | USD219289
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Polar
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| 英文关键词: | ice stream
; ice
; fast ice motion
; ice/bed interface
; ice sheet dynamics
; ice sheet mass balance
; fast ice velocity
; local ice thickness
; ice surface velocity datum
; ice flow
; rock/ice property
; ice flow dynamics
; ice sheet bed property
; basal heterogeneity
; basal control
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| 英文摘要: | This project evaluates the role that water and rock/ice properties at the base of a fast moving glacier, or ice stream, play in controlling its motion. In Antarctica, where surface melting is limited, the speed of ice flow through the grounding zone (where ice on land detaches, and begins to float on ocean water) controls the rate at which glaciers contribute to sea level rise. The velocity of the ice stream is strongly dependent on resistance from the bed, so understanding the processes that control resistance to flow is critical in predicting ice sheet mass balance. In fact, the Intergovernmental Panel on Climate Change (IPCC) recognized this and stated in their 4th assessment report that reliable predictions of future global sea-level rise require improved understanding of ice sheet dynamics, which include basal controls on fast ice motion. Drilling to obtain direct observations of basal properties over substantial regions is prohibitively expensive. This project uses passive source seismology to "listen to" and analyze sounds generated by water flow and/or sticky spots at the ice/bed interface to evaluate the role that basal shear stress plays in ice flow dynamics. Because polar science is captivating to both scientists and the general public, it serves as an excellent topic to engage students at all levels with important scientific concepts and processes. In conjunction with this research, polar science educational materials will be developed to be used by students spanning middle school through the University level. Starting in summer 2015, a new polar science class for high school students in the California State Summer School for Mathematics and Science (COSMOS) will be offered at the University of California-Santa Cruz. This curriculum will be shared with the MESA Schools Program, a Santa Cruz and Monterey County organization that runs after-school science clubs led by teachers at several local middle and high schools with largely minority and underprivileged populations.
This proposal extends the period of borehole and surface geophysical monitoring of the Whillians Ice Stream (WIS) established under a previous award for an additional 2 years. Data from the WIS network demonstrated that basal heterogeneity, revealed by microseismicity, shows variation over scales of 100's of meters. An extended observation period will allow detailed seismic characterization of ice sheet bed properties over a crucial length scale comparable to the local ice thickness. Due to the fast ice velocity (>300 m/year), a single instrumented location will move approximately 1 km during the extended 3 year operational period, allowing continuous monitoring of seismic emissions as the ice travels over sticky spots and other features in the bed (e.g., patches of till or subglacial water bodies). Observations over ~1km length scales will help to bridge a crucial gap in current observations of basal conditions between extremely local observations made in boreholes and remote observations of basal shear stress inferred from inversions of ice surface velocity data. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/93515
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Susan Schwartz. High Resolution Heterogeneity at the Base of Whillans Ice Stream and its Control on Ice Dynamics. 2014-01-01.
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