ESA animations show 25 years of glacier movement in a single second
A researcher at Switzerland's
University of Zurich has combined 25 years worth of satellite imagery
to show the complex behavior of glaciers in a single second. The
effort made use of data collected by NASA's Landsat satellites, focusing on the Karakoram mountain range in Asia.
The animations were created by glaciologist Dr. Frank Paul, and form part of the ESA's Climate Change Initiative, which is combining datasets to build the best possible picture of glacier movement. The GIFs were made by combining between seven and 15 false-color images taken by three different Landsat satellites between the years 1990 and 2015. The glaciers can be seen in light blues to cyan, with water in dark blue, vegetation in green, bare ground in brown and clouds in white.
The animations focus on four regions – Panmah, Skamri-Sarpo Laggo, Baltoro and Shaksgam – and show the movement of the glaciers with a level of clarity that ground-based cameras simply can't provide. Rather than focusing on any single glacier front, the satellite imagery provides a look at the big picture, and by using Landsat imagery, allows us to see the changes over a long period of time.
With the movement sped up some 800 million times, the tiny movements of the glacier can be easily seen, showing that they're not retreating, but surging or advancing, flowing into one another. They're much easier to process than side-by-side images, where the human eye can struggle to easily pick out differences.
The images are certainly impressive, and do a good job of conveying both the scale and complexity of the changes. That said (and as Dr. Paul points out), given access to the data, such animations are easy to create.
"I like the idea of applying an 'old-school' and very simple file format, along with freely available software, to do something that is difficult to achieve with other formats or commercial software," says Dr Paul. "But most importantly anybody can create these animations. Everything required to do it – both images and software – is freely available, so I recommend trying this at home."
The work was published in the journal The Cryosphere.