A massive waterfall formed on Greenland's ice sheet. Here's why it matters
格陵兰冰盖上形成了一个巨大的瀑布。我们要重视它
By Gianluca Mezzofiore ︱ December 4 , 2019
剪辑：BM ︱翻译：Ray︱校对：Sally
What may have been the world's tallest waterfall briefly formed on Greenland's ice sheet last year, draining a meltwater lake of 5 million cubic meters of water -- equivalent to 2,000 Olympic-sized swimming pools -- in just five hours.
这可能是去年在格陵兰冰原上短暂形成的世界上最高的瀑布，它在短短的5个小时内将一个500万立方米的融水湖——相当于2000个奥运会规模的游泳池——排干。Scientists from the University of Cambridge in the UK recorded the extraordinary phenomenon through the use of aerial drones.英国剑桥大学的科学家通过使用无人机记录了这一非凡现象。Their study, published this week n the journal Proceedings of the National Academy of Sciences, investigates the link between this transfer of meltwater to the bottom of the ice and rising global sea levels. Greenland has the world's second-largest ice sheet, and is the single largest contributor to global sea-level rise, the study said.他们的研究发表在本周的《美国国家科学院院刊》上，他们调查了融水向冰层底部转移与全球海平面上升之间的联系。研究称，格陵兰岛拥有世界第二大冰盖，是全球海平面上升的最大促成因素。"Before this study, we already knew that many lakes drain and that fractures may be important in the lake drainage process, but the formation of fractures in terms of 'where', 'when' and 'how' has not been studied before, at least not with the resolution and details featured in our work," one of the researchers, Poul Christoffersen, from Cambridge's Scott Polar Research Institute, who led the research told CNN via e-mail.“在这项研究之前，我们已经知道许多湖泊在排水，裂缝在湖泊排水过程中起很重要的作用，但裂缝的形成，包括‘何处’、‘何时’和‘如何’等方面，以前没有进行过研究，至少在我们的工作中没有这方面的具体的说法，”研究人员之一，来自领导这项研究的剑桥斯科特极地研究所的波尔·克里斯托弗森，通过电子邮件告诉CNN。Caused by cracks forming on the ice sheet, these cascades are responsible for dumping huge quantities of surface water to the ice bed, where it can accelerate the movement of ice towards the sea. After draining, lakes leave behind holes called moulins, which allow meltwater to continue to travel to the bottom of the ice sheet.由于冰盖上形成裂缝，这些瀑布向冰床倾倒大量地表水，从而加速冰向海洋的运动。在排水之后，湖泊会留下一个叫做蜗穴的洞，让融水继续流向冰盖的底部。"When trigger lakes drain, the water lubricates the bed and the ice flow becomes faster," Christoffersen said.克里斯托弗森说：“当触发湖泊排水时，水润滑了河床，冰变得漂流得更快。”。"Previously this acceleration was thought to be short-lived, and have little overall impact on the ice sheet, but we have shown that even localized and short-lived accelerations caused by the drainage of trigger lakes can open fractures and result in additional drainages of lakes in a more stable setting."“以前，这种加速被认为是短暂的，对冰盖的整体影响不大，但我们已经证明，即使是触发湖泊排水引起的局部和短暂的加速，也会导致裂缝张开，导致湖泊在更稳定的环境中增加排水。”Formed during the summer as the weather warms, the 'trigger lakes' such as the one the scientists observed at Store Glacier, in northwest Greenland, can cause a chain-reaction so that up to 50 or more lakes nearby can drain rapidly over the course of a few days, Christoffersen said.克里斯托弗森说，这些“触发湖”形成于夏季，随着天气变暖，科学家在格陵兰岛西北部的冰峡湾观测到的“触发湖”会引起连锁反应，因此附近多达50个或更多的湖泊可以在几天内迅速排干。At its peak, the cascade was 950 cubic meters per second, which is roughly half of the flow of Niagara Falls or one Olympic sized swimming pool every three seconds, he said. The water was plunging "pretty much exactly" 1,000 meters (3,281 feet), said Christoffersen.他说，在最高峰时，瀑布流量为950立方米/秒，大约是尼亚加拉瀑布流量的一半，或者每3秒就有一个奥运会规模的游泳池的水量流走。克里斯托弗森说，湖水“几乎完全”下沉了1000米（3281英尺）。Angel Falls in Venezuela is the world's highest waterfall, standing at around 3,210 feet.委内瑞拉的天使瀑布是世界上最高的瀑布，高约3210英尺。"This discharge increased the ice flow from two meters per day to five meters per day as the water delivery took place. This acceleration had a sudden impact on the ice sheet in terms of stress and ice deformation, and these dynamic impacts explain why lakes situated in places where fractures do not naturally form, still drain rapidly," said Christoffersen.“这一流量使冰的漂行从每天两米增加到了每天五米，因为湖水已经排出。这种加速作用在应力和冰变形方面对冰盖产生了突然的影响，而这些动态的影响解释了为什么位于裂缝没有自然形成的地方的湖泊仍然迅速流失湖水，”克里斯托弗森说。Christoffersen said climate change plays a key role in the increase of meltwater production, as global temperatures rise.克里斯托弗森说，随着全球气温的上升，气候变化对融水量的增加起着关键作用。"More and more melt water is being produced and melting extends to higher and higher elevations," he said. "Lakes are growing larger and more numerous and forming at higher elevations. Some as high as 2 kilometers above sea level. This means that networks of lakes draining in cascading events are likely to grow larger."他说：“正在产生越来越多的融水，融解延伸到越来越高的海拔。”湖泊越来越大，越来越多，形成在更高的海拔。有的高于海平面2公里。这意味着在泻水出现时排水的湖泊网络可能会变得更大。”南极的冰已经化了不少了。 英语读头条（第561期）
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