How researchers use the latest Earth observation data - Part one
Researchers from across the globe are in Oberpfaffenhofen for the TerraSAR-X and TanDEM-X Science Meeting. For four days, from 17 to 20 October 2016, they have the opportunity to present their results from the data acquired by the two Earth observation satellite missions and exchange information. Here, approximately 200 presentations give an overview of the latest research in satellite-based Earth observation. The radar data are used in various scientific fields, from climate research to geosciences to forestry, infrastructure planning and remote sensing methodology.
Covering the Science Meeting, the Space Blog presents some of the work presented. The short examples provided outline how the data of the German radar satellites support researchers worldwide.##markend##
Lakes on ice
During the summer months, the surface of glacier melts, forming so-called supraglacial lakes in hollows. In the first image, these lakes are easily identified by their highly characteristic shades of blue. Glaciologists are keeping a keen eye on them, as they can accelerate glacial movement: If the load of the lake becomes too great, the water can reach the base of the glacier within just a few hours, through glacier mills or crevasses. Here, the water acts as a lubricating film, increasing slippage of the glacier. The 79°N glacier in Northeast Greenland alone exhibits well over one hundred such lakes.
Angelika Humbert from the Alfred Wegener Institute is using the TanDEM-X digital terrain models to accurately measure water levels. Drainage of the lake can be seen as a decrease (red) and refilling of the lake as an increase (blue). “The many images that TanDEM-X captured of the 79°N glacier between 2013 and 2015 enable us to more accurately determine annual and seasonal changes," the glaciologist explains, adding: "With the Tandem-L mission, we could observe the melting season even in weekly cycles at high resolution – and, in the case of open lakes, we can also anticipate excellent elevation information in the L-band."
Secrets below the ice
The raw beauty of the glacial landscapes with mountain peaks and long valleys, interspersed with grooves and elevations that stretch across hundreds of kilometres and branch out until they appear to peter out. Where do these structures come from? The TerraSAR-X radar images are providing Humbert with a first overview of the polar landscapes. The 3D images acquired by TanDEM-X are thereby revealing the topographical mystery: gullies beneath the glacial ice, formed by the erosive melt water. The image of the Filchner Ice Shelf in the Antarctic, for example, reveals that the ice within the gully is approximately 200 metres thinner than the surrounding surface ice. The accurate radar data of the ice thickness above and below the glacier surface is helping glaciologists better understand the melting processes and movement of the ice masses.
View of coastal areas and tidal flats
The sea is changeable and shapes its coastal regions. How can such dynamic, extensive areas be mapped most effectively? This question is being investigated by researchers Ryu Joo-Hyung from the Korean Ocean Satellite Center (KIOST) and Seung-Kuk Lee of NASA GSFC. Their promising approach: A combination of aerial images acquired by unmanned aerial vehicles (UAV) and radar data sets from TanDEM-X. At the Science Meeting, they are presenting an elevation model of a coastal area with extremely high resolution, on both the horizontal and vertical plane. The radar data will, in future, enable scientists to observe coastal areas over time and thereby gain new insights.