The Effect of Superglacial Débris on the Advance and Retreat of Some Canadian Glaciers
The Effect of Superglacial Débris on the Advance and Retreat of Some Canadian Glaciers
复制标题
冰上碎片对加拿大部分冰川进退的影响
DOI：
10.1086/621194
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发表时间：
1904
期刊：
影响因子：
--
通讯作者：
I. H. Ogilvie
中科院分区：
文献类型：
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作者：
I. H. Ogilvie
现在正在从全球各地收集关于冰川运动速度、冰川进退量和同类统计数据的观测数据，以期推断出目前冰川运动的一些一般规律，并对过去的冰川状况有所了解。显然，冰川的推进受到两个因素的影响：(1)运动速度，(2)废物速度。任何增加运动速度的原因都会倾向于推动冰面向前推进，而这种推进只会受到废物数量的限制。废物将会增加，要么是因为温度上升，导致熔化和蒸发增加，要么是因为暴露在干燥空气中产生蒸发。因此，冰川可以通过增加运动或减少废物来推进。对现有冰川进退的观察几乎完全与影响冰川运动速度的因素有关。废品率通常被忽视，或者被认为是次要的。对于任何一座冰川来说，这可能是次要的，因为冰点附近的每日和年度温度变化在连续几年大致相同。因此，可以安全地假设，任何一座冰川的失水量每年都会有所不同，主要是根据冰质量的变化比例，而冰质量的变化反过来又受运动速度的影响。但是，当比较不同的冰川时，很明显，废物的速度是决定冰锋位置的一个重要因素。冰川的运动速度不同，它们的运动速度也不同，运动缓慢、消耗缓慢的冰川可能会比运动速度更快、但运动速度也更快的冰川前进得更远。
OBSERVATIONS on rates of motion, amounts of advance or retreat of glaciers, and kindred statistics are now being collected from all quarters of the globe in the hope of deducing some general laws of ice-motion in the present, and of throwing some light on glacial conditions in the past.' Obviously the advance of glaciers is influenced by two factors: (i) rate of motion, and (2) rate of waste. Any cause increasing the rate of motion will tend to push the front of the ice forward, and this advance will be held in check only by the amount of waste. Waste will be increased either by a rise in temperature, producing increased melting and evaporation, or by increased exposure to dry air producing evaporation. A glacier may advance, therefore, either from increased motion or from decreased waste. Observations on the advance or retreat of existing glaciers have been correlated almost exclusively with the factors influencing rate of motion. The rate of waste is usually neglected, or is regarded as of secondary importance. Of secondary importance it may be in the case of any one glacier, since the daily and annual ranges in temperature about the freezing-point are approximately the same in successive years. Hence it may be safely assumed that the amount of water lost by any one glacier will differ from year to year mainly in proportion to changes in the mass of the ice, which in turn is affected by rate of motion. But when different glaciers are compared, it becomes evident that rate of waste is an important factor in determining the position of the ice-front. Glaciers differ from each other in rate of waste, as they do in rate of motion, and a sluggish glacier, slow-moving and slow-wasting, may advance farther than one whose rate of motion is faster, but whose rate of waste is also faster.