無人機(jī)實時顯示格陵蘭冰蓋破裂

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.

科學(xué)家星期一說，他們用無人駕駛飛機(jī)觀察了格陵蘭冰原上一個湖泊的快速破裂和排水，這一現(xiàn)象可能因氣候變化而變得更加頻繁。

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.

冰蓋通常厚約一公里(1090碼)，在夏季，一些地表融化并形成數(shù)千個湖泊是正常的。

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.

許多湖泊在幾小時內(nèi)就排干了水，在冰的底部形成了巨大的開口，深達(dá)一公里。在接下來的融水季節(jié)里，來自地表溪流的融水會繼續(xù)順著它們向下流動，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.

這一過程很難直接觀察到，但劍橋大學(xué)斯科特極地研究所的一組冰冰學(xué)家很幸運，他們于2018年7月抵達(dá)格陵蘭島西北部的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.

在它們到達(dá)后的幾天，在5個小時內(nèi)，三分之二的湖泊或大約500萬公升的水通過裂縫從地表消失。

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

無人機(jī)前后拍攝的航拍照片顯示，一個深藍(lán)色的橢圓形縮小為一個更小、更淺、更淺的藍(lán)色圓圈。

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".

這項發(fā)表在《美國國家科學(xué)院院刊》上的研究的第一作者之一湯姆丘德利(Tom Chudley)告訴法新社記者，“無人機(jī)能做的就是讓我們在地面科學(xué)家無法安全進(jìn)入的地區(qū)進(jìn)行這種高質(zhì)量的測量”。

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.

通過利用船上的GPS，該團(tuán)隊能夠定位并將數(shù)千張照片拼接在一起，這些照片反過來又被用來創(chuàng)建詳細(xì)的3D重建冰蓋的表面。

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).

冰川是一條冰河，在自身重量的作用下緩慢地向海洋移動。當(dāng)它到達(dá)海中時，它會分裂成冰山，約占格陵蘭島對海平面上升的貢獻(xiàn)的40%(其余部分來自冰川的實際融化)。

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.

儲存冰川以每年600米(660碼)的速度前進(jìn)。這個研究小組還包括來自阿伯里斯特威斯大學(xué)和蘭開斯特大學(xué)的科學(xué)家，他們發(fā)現(xiàn)湖水的突然排泄使湖水的速度暫時從每天2米提高到5米。

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

落在冰下的水起到潤滑劑的作用。

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

研究小組說，更令人驚訝的是，這片水床將冰川的高度提高了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.

劍橋大學(xué)的博士生查德利說：“這是一公里長的冰上升了半米，所以你可以想象其中的壓力。”。

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.

研究小組的論文更詳細(xì)地描述了這些巨大裂縫的形成過程，進(jìn)而形成了加速冰川運動的水床。

"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.

查德利說：“當(dāng)我們看到格陵蘭島氣候變化的進(jìn)展時，我們看到了更多的湖泊，看到它們越來越大，們看到它們越來越高，進(jìn)入冰蓋較冷的區(qū)域，我們可以看到一些湖泊開始流失。”。

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

他警告說:“我們可能正在增加湖泊的數(shù)量，這些湖泊正在流向我們以前沒有發(fā)現(xiàn)的新地方。”