Ice shelves
Ice shelves
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冰架
作者：
A. Bauer
冰川学家们一定很高兴看到像H.韦克斯勒成功地研究了像冰架这样复杂的问题，从而支持了他们。总的来说，我认为最根本的问题是冰流问题.以罗斯冰架为例，我们可以试着了解它的质量平衡。面积51万公里。2和17厘米的积累。水（已确定由沙克尔顿在1908年），总的年积累是87 km.3水。忽略冰上和冰下融化，流量主要以冰山的形式。总损失为：400米。年人工老化X 850公里。（前）X 250米。（厚度）= 85 km.3冰，即77 km）水/年。然后，有87 km 3的积累和77 km 3的冰山损失。因此，罗斯冰架似乎几乎处于平衡状态。但实际上并非如此，因为我们必须加上从冰帽上下来的大冰川（例如比尔德摩尔冰川）的贡献，这是很难估计的。似乎明智的是，在其汇合处与冰架沿沿着40公里。正面，Beardmore冰川厚度约为500 m。其速度约为5 m。/天;这给出了33 km.3水/年的贡献。我们还必须加上所有其他冰川的贡献。这不是增加了一倍的积累吗？罗斯冰架是平衡的（根据奥尔格的估计），它的积累不会比它的排放更重要。因此，我们必须推断，作为冰山的排放必须比估计的排放更重要。这样做的一个后果是，必须存在像格陵兰冰席排水一样的冰流。有活跃区和平静区，前者有块运动，正如芬斯特瓦尔德所描述的，它不遵守通常的流动定律。在冰架的排泄和冰川的贡献，即罗斯冰架的物质平衡问题得到澄清之前，我认为很难解决Wexler博士所研究的问题。通过研究，我们必须设法确定（1）从冰帽上下来的冰川的贡献，（2）冰山在罗斯冰架前缘的运动和损失。这两个问题可以通过Aeria I摄影测量来解决，而无需地形准备，遵循I.G.Y.期间开发的方法。用经纬仪跟踪guirling标记来尝试经典的大地测量方法来确定速度是荒谬的。当冰流已确定，冰架前缘和丰水冰川的流速已知时，流量可以用已知的厚度值来估算。我们希望在不久的将来进行这种研究。小刺蛾E.piditioll G/aci%gifjue illtema/janale all GrocllLal/d，A. BAUER 46 ruc Geiler，Stmsbourg，法国1960年5月3日
Glaciologists must be pleased to see that a scientist as serious as Dr. H. Wexler has come to their support by studying with success a problem as complex as that of ice shelves. I Generally speaking, I believe that the fundamental problem is one of ice flow. Taking the Ross Ice Shelf as an example, we can try to get an idea of its mass balance. With a surface area of 510,000 km. 2 and an accumulation of 17 cm. water (already determined by ShackIeton in 1908), the total annual accumulation is 87 km.3 water. Neglecting superand subglacial melting, discharge is mainly in the form of icebergs. The total loss is: 400 m./yr. X 850 km. (front ) X 250 m. (thickness) = 85 km.3 of ice, i.e. 77 km) water/yr. Then, there is 87 km.3 of accumulation and 77 km.3 of loss as icebergs. It would therefore seem that the Ross I ce Shelf is almost in balance. But in reality it is not, for we must add the contribution of big glaciers (for instance, the Beardmore Glacier) coming down from the ice cap, which is difficult to estimate. It seems sensible that, at its confluence with the ice shelf along a 40 km. front, the thickness of the Beardmore G lacier is about 500 m. and its velocity about 5 m. /day; this gives a contribution of 33 km.3 water/yr. We must also add the contributions of all the other glaciers. Do these not double the accumulation? The Ross Ice Shelf is (by rOllgh estimate) balanced and its accumulation cannot be more important than its discharge. We must therefore infer that the discharge as icebergs must be more important than the es timated one. A consequence of this is that there must exist ice streams like those draining the Greenland I ce Sheet. There are active zones and quiet zones, the former having a block-movement, as described by Finsterwalder, whi ch does not obey the ordinary laws of flow. Until the questions of ice shelf discharge and contribution of glaciers, i.e. the mass balance of the Ross I ce Shelf, have been clarified , I think it will be difficult to solve the problem studied by Dr. Wexler. By research we must try to determine ( I ) the contribution of g laciers coming down from the ice cap, and (2) the movement a nd the loss by icebergs a long the front of the Ross Ice Shelf. These two problems can be solved by aeria I photogrammetry without topographic preparation, following the methods developed during the I.G.Y. It would be ridiculous to try classical geodetic methods of velocity determination by following guirling marks with a theodolite. When the ice strea ms have been determi ned and the respective velocities of the front of the ice shelf and affluent glaciers are known , th e discharge can be esti mated by using known values for thickness. We hope that such studies will be undertaken in the near future. E.piditioll G/aci%gifjue illtema/janale all GrocllLal/d, A. BAUER 46 ruc Geiler, Stmsbourg, Fral/ce. 3 M ay 1960 REFERE CE