Monitoring the changes of our lifetime

Greenland, rugged and wild, is covered by a massive ice sheet that represents roughly 80 % of its surface. Glaciers break free of this ice sheet and become slow flowing rivers of ice that are constantly moving, being pushed by their own massive weight towards the sea. There are many reasons why researchers have recently taken an enormous interest in studying the secrets of Greenland’s ice. One is that Greenland is especially vulnerable to climate change; the ice sheet is melting faster than any other body of ice in the world and the glaciers are moving ten times faster towards the sea than they did just five years ago. Another reason is that this country’s ice represents roughly eight percent of all freshwater found on Earth. Should these glaciers melt, the meltwater would be enough to raise the sea level by over seven metres (20 feet), displacing millions of people on this planet. This will have serious consequences on our environment, making it extremely important to monitor these changes, which are occurring during our lifetime.

Luc Moreau, a glaciologist based in Chamonix, France, has been studying the impressive four kilometre (two and a half miles) wide Eqip Sermia glacier in West Greenland for over three years. Luc, along with, the SPELEICE association and the MONALISA production company, recently organised an expedition to collect data on the speed of this glacier’s melt flow and to understand how this glacier’s ice moulins (deep holes that transport meltwater through glaciers) affect the speed of its melting. Accompanying them was Farouk Kadded, product manager of Geomatics at Leica Geosystems France, and together they set out using the state-of-the art Leica Nova MS50 MultiStation and real-time GNSS positioning instruments Leica GS14 antenna and Leica GS10 receiver. The MultiStation was chosen because it was capable of making accurate, reflectorless 3D scans from a distance of 1 – 2 km (0.6 – 1.2 mi), was lightweight and compact enough to be carried in a backpack and was proven to be reliable and rugged. It was also the only scanner on the market that offered all four technologies needed: total station, scanning, GNSS and imaging.

Measuring the Eqip Sermia’s movement flow
During his last expeditions, Luc set up a camera that took pictures daily over the last few years. He was able to identify the changes in the glacier size by piecing together a “timelapse” film from the images taken by this camera. This film, when accompanied by the collected topographic data of the Leica Geosystems equipment, could be used to calculate the length and speed of the flow of the Eqip Sermia glacier.

卢克和Farouk但书之后d stable ground for the GS10 receiver to serve as a reference point, they started out looking for the ideal measuring positions on the glacier. This was a dangerous task on the quickly shifting glacier surface with its deep and deadly ice chasms. Carrying the MultiStation, a tripod, a reflector target, the rugged Leica GS14 antenna and a pole, they first set up the MultiStation on the stable left bank with the Leica GS14 GNSS antenna on top to get the exact coordinates for the MS50 to measure the selected points at a range of 1.3 kilometres (0.8 miles). After this, they perilously crossed the glacier to position a reflective target. For four consecutive days, they collected position data at the same time of day to calculate the glacier melt flow over a 24-hour period.

The glacier moved at a rate of up to 30 centimetres (12 inches) an hour, so the team had to work fast. Images were first taken by the MultiStation of several seracs, or ice towers, to help Luc and Farouk easily relocate the same points the next day.

结果证明，冰川的运动每天高达7米（23英尺）。2012年进行的最后一次测量表明，EQIP Sermia每天移动3米（10英尺）。与世界各地的其他冰川相比，这种流程每天移动大约30厘米（12英寸）时，这种流程令人震惊。该团队还证明了冰川在上个月损失了大约500米（1,640英尺）。该团队打算实现的另一个目标，即使用莉卡·多斯（Leica Multistation）进行3D扫描，以实现法国北极探险家Paul-émileVictor用作其探险基地的历史舱者的后代，也成功完成了。此外，还发现了一个在eqip sermia表面上几公里的大湖。如果这种水以某种方式进入裂缝，则可能导致冰川崩溃。最终结果还证明，冰川在海面以下融化的速度比上面的速度快100倍。

测量内部冰毛琳
在进行了同样的时间之后，探险家Paul-ÉmileVictor在60年前就遇到了冰川冰盖，这是一段漫长的跋涉。该扫描将确定黄昏内的水是否确实到达了冰川下方的岩石床。为什么这些大师对研究冰川如此重要？由于格陵兰岛的全球变暖比世界其他地区更大，因此在非常温暖的日子里，冰川的湖泊出现在冰川的表面上。多余的湖水产生的河流以惊人的速度融化冰。如果这种水进入红磨坊，它将开始旋转并侵蚀冰，并在格陵兰岛基岩上的冰川底部找到道路。这种水在冰川下积聚，像润滑剂一样工作。冰川很容易在水面上滑动，重力力将冰的巨大重量推向海洋。

The meltwater’s journey
卢克（Luc）和法鲁克（Farouk）设法在冰露头（Ice Roulin）内部的部落上建立了多个杂货店，以扫描冰裂缝的细节。随着一些红牛的深度高达200米（650英尺），这确实令人兴奋。从来没有做过如此准确的扫描，即水的流量如何形成冰川红磨室内的角落和缝隙，将其进度记录到冰的底部。

Working inside this hole is not without its dangers. Should the surface temperature fluctuate as much as 1-2°C (34-36°F), glacier water could start to melt and flow into the moulin, flooding everything. Scanning took an entire day, but they were able to scan the moulin in its entirety, measuring vertically, bit by bit, from the river that created it to its deepest part, collecting roughly 500,000 highly detailed points. Depth, circumference and width can all be provided by a 3D scan taken by the Leica MS50 MultiStation and the results were fascinating.

“以这种方式进行衡量的想法是要拥有大红牛的所有尺寸，以便欣赏其随着时间的流逝和冰的变形。结果被证明非常有效，模型视觉效果非常好，并且该设备非常适合这种开口 - 只要您的天气良好！”卢克·莫罗（Luc Moreau）兴奋地说。

3D扫描证明了Leica MS50多站的多功能性及其在特殊情况下的鲁棒性。它的新程序和功能共同努力，整合新技术，使测量更加可靠，更快，更完整，使研究人员能够接收他们所需的信息。与处于其领域最前沿的公司合作，只能帮助研究人员促进他们理解不断变化的气候。

Written by Farouk Kadded and Luc Moreau