Measurement of temperature in a margin of Ice Stream B, Antarctica: implications for margin migration and lateral drag
Measurement of temperature in a margin of Ice Stream B, Antarctica: implications for margin migration and lateral drag
复制标题
南极洲冰流 B 边缘的温度测量：对边缘迁移和横向阻力的影响
DOI：
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发表时间：
1998
影响因子：
3.4
通讯作者：
Christopher F. Larsen
中科院分区：
文献类型：
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作者：
William D. Harrison;K. Echelmeyer;Christopher F. Larsen
摘要从1992年到1994年，在南极B冰流混乱的南缘及其周围测量了冰温。由于冬季冷空气的积聚，混乱区30m深处的温度比邻近的未破裂冰层低约12K。在大于150m的深度，有明显的证据表明，由于边缘带的大剪切变形速率，冰的内部加热。对裂缝下冷却深度和内部加热的分析提供了两条信息。首先，在过去的半个世纪中，边缘顶部三分之一的侧向剪应力平均为2.0x105pa，其次，边缘向外移动的平均速度为7.3m a−1。这些值不涉及任何关于冰定律的假设。不确定性约为20%。侧向剪应力的大小表明，冰流上的阻力主要沿冰流两侧。
Abstract Ice temperature was measured in and around the chaotically crevassed south margin of Ice Stream B, Antarctica, from 1992 to 1994. The temperatures at 30 m depth in the chaotic zone are about 12 K lower than in the adjacent uncrevassed ice, due to the ponding of cold winter air. At depths greater than 150 m, there is clear evidence of internal heating of the ice due to the large shear déformation rate in the marginal zone. Analysis of the depth of cooling below the crevasses and of the internal heating gives two pieces of information. First, over the last half century the lateral shear stress averaged 2.0 x 105 Pa in the top third of the margin and, second, the margin moved outward at an average rate of 7.3 m a−1. These values do not involve any assumptions about the How law of ice. The uncertainties are roughly 20%. The value of lateral shear stress indicates that the most of the drag on the ice stream is along its sides.