Melting and freezing beneath the Ross ice streams, Antarctica
Melting and freezing beneath the Ross ice streams, Antarctica
复制标题
南极洲罗斯冰流下方融化和冻结
DOI：
10.3189/172756504781830295
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发表时间：
2004
影响因子：
3.4
通讯作者：
H. Engelhardt
中科院分区：
文献类型：
--
作者：
I. Joughin;S. Tulaczyk;D. Macayeal;H. Engelhardt
本文对南极西部冰流底部的温度梯度和融化速率进行了估算。测量的速度被用来包括温度模型中的水平平流和应变加热的影响，并确定剪切加热的床。我们模拟的温度与在稳定流区域钻孔测量的温度吻合得很好。我们发现，冰流支流和内陆冰约占87%的罗斯冰流及其集水区下产生的总融化。我们的估计表明，Whillans冰流和冰流C（即使是活跃的）的冰原有大面积的基础冻结，证实了早期的估计，从上游进口的水是必要的，以维持运动。惠兰冰流相对较低的融化速率与过去几十年的减速观测结果一致，并表明未来可能会发生关闭，可能在本世纪内。虽然在冰流D和E下面有基底冻结的口袋，但有更大面积的基底融化，产生足够的融化来抵消冻结，这与过去一千年这些冰流相对稳定的流动的推断一致。
Abstract We have estimated temperature gradients and melt rates at the bottom of the ice streams in West Antarctica. Measured velocities were used to include the effects of horizontal advection and strain heating in the temperature model and to determine shear heating at the bed. Our modeled temperatures agree well with measured temperatures from boreholes in regions of steady flow. We find that ice-stream tributaries and the inland ice account for about 87% of the total melt generated beneath the Ross ice streams and their catchments. Our estimates indicate that the ice plains of Whillans Ice Stream and Ice Stream C (even when active) have large areas subject to basal freezing, confirming earlier estimates that import of water from upstream is necessary to sustain motion. The relatively low melt rates on Whillans Ice Stream are consistent with observations of deceleration over the last few decades and suggest a shutdown may take place in the future, possibly within this century. While there are pockets of basal freezing beneath Ice Streams D and E, there are larger areas of basal melt that produce enough melt to more than offset the freezing, which is consistent with inferences of relatively steady flow for these ice streams over the last millennium.