无人机实时显示格陵兰冰盖破裂

Scientists said Monday they had used a drone to observe the rapid fracturing and draining of a lake on the Greenland ice sheet, a phenomenon that may become more frequent as a result of climate change.

科学家星期一说，他们用无人驾驶飞机观察了格陵兰冰原上一个湖泊的快速破裂和排水，这一现象可能因气候变化而变得更加频繁。

The ice sheet is typically about a kilometre thick (1090 yards), and during summer, it is normal for some of the surface to melt and form thousands of lakes.

冰盖通常厚约一公里(1090码)，在夏季，一些地表融化并形成数千个湖泊是正常的。

Many of the lakes drain in just a few hours, creating vast openings at the base of the ice, up to a kilometre deep. Meltwater from surface streams continues to flow down them for the rest of the melt season, creating some of the world's largest waterfalls.

许多湖泊在几小时内就排干了水，在冰的底部形成了巨大的开口，深达一公里。在接下来的融水季节里，来自地表溪流的融水会继续顺着它们向下流动，形成世界上最大的瀑布。

This process has been extremely difficult to observe firsthand, but a group of glaciologists from the Scott Polar Institute at the University of Cambridge were fortunate when they arrived at the Store Glacier in northwest Greenland in July 2018.

这一过程很难直接观察到，但剑桥大学斯科特极地研究所的一组冰冰学家很幸运，他们于2018年7月抵达格陵兰岛西北部的Store冰川。

A few days after their arrival, over the course of five hours, two-thirds of the lakes or roughly 5 million litres of water disappeared from the surface through a fracture.

在它们到达后的几天，在5个小时内，三分之二的湖泊或大约500万公升的水通过裂缝从地表消失。

Aerial photography captured by the drone from before and after showed a dark blue oval shrink into a smaller, shallower and lighter blue circle.

无人机前后拍摄的航拍照片显示，一个深蓝色的椭圆形缩小为一个更小、更浅、更浅的蓝色圆圈。

Tom Chudley, co-first author of the study that appeared in the Proceedings of the National Academy of Sciences told AFP that the "thing that drones can do is allow us to take these kind of high quality measurements in regions that aren't safe to access for scientists on the ground".

这项发表在《美国国家科学院院刊》上的研究的第一作者之一汤姆丘德利(Tom Chudley)告诉法新社记者，“无人机能做的就是让我们在地面科学家无法安全进入的地区进行这种高质量的测量”。

By making use of on-board GPS, the team was able to geo-locate and stitch together thousands of photos that were in turn used to create detailed 3D reconstructions of the ice sheet's surface.

通过利用船上的GPS，该团队能够定位并将数千张照片拼接在一起，这些照片反过来又被用来创建详细的3D重建冰盖的表面。

Raising the glacier

冰川抬高

A glacier is a river of ice that moves slowly under its own weight toward the ocean. When it reaches the sea, it breaks off into icebergs, which represent about 40 percent of Greenland's contribution to rising sea levels (the rest is from the actual melting of the glaciers).

冰川是一条冰河，在自身重量的作用下缓慢地向海洋移动。当它到达海中时，它会分裂成冰山，约占格陵兰岛对海平面上升的贡献的40%(其余部分来自冰川的实际融化)。

The Store Glacier advances at a rate of 600 metres per year (660 yards). The team, which also included scientists from Aberystwyth and Lancaster Universities, found that the sudden drainage of the lake temporarily increased its speed from two to five metres per day.

储存冰川以每年600米(660码)的速度前进。这个研究小组还包括来自阿伯里斯特威斯大学和兰开斯特大学的科学家，他们发现湖水的突然排泄使湖水的速度暂时从每天2米提高到5米。

The water that fell under the ice served as a lubricant.

落在冰下的水起到润滑剂的作用。

Even more surprising was that this bed of water lifted the glacier's height by 55 centimetres (22 inches), the team said.

研究小组说，更令人惊讶的是，这片水床将冰川的高度提高了55厘米(22英寸)。

"That's a kilometre of ice lifted up half a meter, so you can imagine the kind of pressures that were involved," said Chudley, a doctoral student at Cambridge.

剑桥大学的博士生查德利说：“这是一公里长的冰上升了半米，所以你可以想象其中的压力。”。

The team's paper describes in fuller detail the formation of these vast fractures, which in turn create water beds that accelerate the glacier's movement.

研究小组的论文更详细地描述了这些巨大裂缝的形成过程，进而形成了加速冰川运动的水床。

"As we see climate change progressing in Greenland, we're seeing more lakes, and we're seeing them get larger, and we're seeing them higher up into the colder section of the ice sheet, and we can see that some of these lakes are beginning to drain," said Chudley.

查德利说：“当我们看到格陵兰岛气候变化的进展时，我们看到了更多的湖泊，看到它们越来越大，们看到它们越来越高，进入冰盖较冷的区域，我们可以看到一些湖泊开始流失。”。

"Potentially we're increasing the amount of lakes that are draining in new places that we haven't previously identified," he warned.

他警告说:“我们可能正在增加湖泊的数量，这些湖泊正在流向我们以前没有发现的新地方。”