The air content of Larsen Ice Shelf
The air content of Larsen Ice Shelf
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DOI：
10.1029/2011gl047245
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发表时间：
2011-05-25
影响因子：
5.2
通讯作者：
Tedesco, Marco
中科院分区：
文献类型：
--
作者：
Holland, Paul R.;Corr, Hugh F. J.;Tedesco, Marco
冰雪的空气含量决定了观测到的冰面海拔变化的影响和原因，但目前只能使用劳动密集型地面技术来测量。这里提出了一种新的方法，利用雷达探测测量将漂浮冰架的总厚度分解为固体冰和冰雪空气(或冰雪水)的厚度。该方法被应用于1997/98年对拉森冰架的航空调查，揭示了空气含量的大空间梯度，这与现有的测量结果和当地的气象相一致。这些梯度似乎是由融水诱导的降雪致密化决定的。我们在拉森C冰架中发现了足够的空气来增加密度，以解释之前观察到的表面下降的原因，而且下降的速度表面上与已公布的融化趋势一致。这并不排除海洋底部融化对海平面下降的贡献，但现代重复调查可以最终区分大气主导的变化和海洋主导的变化。这项技术还有望用于雪密度模型的校准、从表面高程测量得出冰层厚度，以及计算地面冰流量变化对海平面的贡献。引文：Holland，P.R.，H.F.J.Corr，H.D.Pritchard，D.G.Vaughan，R.J.Arthern，A.Jenkins，M.Tedesco(2011)，地球物理，拉森冰架的空气含量。莱特，38，L10503，DOI：10.1029/2011GL047245。
The air content of glacial firn determines the effect and attribution of observed changes in ice surface elevation, but is currently measurable only using labor-intensive ground-based techniques. Here a novel method is presented for using radar sounding measurements to decompose the total thickness of floating ice shelves into thicknesses of solid ice and firn air (or firn water). The method is applied to a 1997/98 airborne survey of Larsen Ice Shelf, revealing large spatial gradients in air content that are consistent with existing measurements and local meteorology. The gradients appear to be governed by meltwater-induced firn densification. We find sufficient air in Larsen C Ice Shelf for increased densification to account for its previously observed surface lowering, and the rate of lowering superficially agrees with published trends in melting. This does not preclude a contribution to the lowering from oceanic basal melting, but a modern repeat of the survey could conclusively distinguish atmosphere-led from ocean-led change. The technique also holds promise for the calibration of firn-density models, derivation of ice thickness from surface elevation measurements, and calculation of the sea-level contribution of changes in grounded-ice discharge. Citation: Holland, P. R., H. F. J. Corr, H. D. Pritchard, D. G. Vaughan, R. J. Arthern, A. Jenkins, and M. Tedesco (2011), The air content of Larsen Ice Shelf, Geophys. Res. Lett., 38, L10503, doi: 10.1029/2011GL047245.