2153 mirrors twist and turn at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Experimental Solar Thermal Power Plant in Jülich, directing sunlight onto a 22-square-metre receiver. TerraSAR-X, the German radar satellite operated by DLR, can also detect the mirrors as they follow the Sun – from more than 500 kilometres above Earth. The reflections of the radar signals make the tower and mirror array appear as bright spots of light.
DLR (CC-BY 3.0).
Christmas Island is a 135-square-kilometre island in the Indian Ocean. In the image acquired with the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X radar satellite, one thing is clear – even today, tropical rainforest proliferates on the island and the coastal cliffs continue to make life difficult for mariners.
British researchers have used images acquired by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X satellite to create a map showing changes in the Santorini archipelago. The cause of the deformation is the Santorini volcano located beneath the archipelago. In some places, the Kameni Islands inside the flooded caldera have risen by eight to 14 centimetres. The breadth of the caldera as a whole has increased by about 14 centimetres since early 2011. In the analysis of the radar data, the red and yellow shading shows the areas where the ground has risen the most. The main island of Thira is unaffected by the deformation, thus appearing blue.
The German Aerospace Center's (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X radar satellite orbits Earth at an altitude of 514 kilometres. It acquired this image of the Bonneville Salt Flats in the USA at 13:40 local time on 23 June 2009. The black represents areas of water, where radar signals transmitted by the satellite are reflected away by the smooth surface of the water. The city of Wendover is conspicuous in the upper half of this space radar image, with the orange colouring indicating a strong increase in the local variance of the return signal, due to direct or multiple reflections off the buildings and streets.
Between the Scottish mainland and the Orkney island of South Ronaldsay, the water flows at very high speed. The German Aerospace Center (DLR) TerraSAR-X and TanDEM-X radar satellites make it possible to identify and analyse these currents from space.
Using TerraSAR X data, Berlin Central Station was measured horizontally and vertically over the course of a year. In the warm season, the steel structure of the building expands; in winter, it contracts again. Based on the coloured dots, the maximum deformation in the course of one year can be seen to be in the millimetre range. The horizontal movement is visible in the left-hand image, and the vertical movement of the station structure is shown in the right-hand image.
Stefan Gernhardt, TU München.
Radar signals from the TerraSAR-X satellite can penetrate the upper layers of snow and ice that cover the Mackenzie River in Canada. The shades of colour enable DLR researchers to draw conclusions about the ice formations and various subsurfaces.
The tents and vehicles are clearly visible in this radar image. The artificial structures have been coloured to make them more easily visible; the actual radar image is black and white.
In this image of the Puyehue-Cordón Caulle region, acquired by TerraSAR-X on 6 July 2011, a newly formed lava field is visible northwest of the prominent Puyehue crater. The light blue coloured area is the lava field that has formed to the west of the new crater.
TerraSAR-X provides a detailed view of the city from over 500 kilometres up. The airport can be seen to the west – the taxiways and runways reflect the radar signals away from the satellite, causing the asphalt surfaces to appear as black lines. There is dense housing where yellow is predominates. The construction of the Bosphorus bridges has been a primary driver for the growth of the city. The urbanisation snakes along the Bosphorus right down to the Black Sea. In the city itself, only a few areas remain undeveloped and are thus shown in green. This is the case on the headland where the Golden Horn, an inlet, extends into the European part. Having an exclusive panoramic view of the city and few neighbours, this is where the Topkapi Palace, the former residence and seat of government of the Sultans, is located. Even the ships that sail on the Sea of Marmara or the Bosphorus do not escape the 'radar eyes' of TerraSAR-X.
This TerraSAR-X image, acquired on 12 March 2011, shows that the port of the Japanese city of Sendai has been devastated by the tsunami. The magenta-coloured areas reveal the extent of damage in the form of boulders and debris deposits; the blue areas are flooded.
Dieses Bild zeigt die Auswirkungen des Tsunamis in einem Vorher-The effects of the tsunami are shown in a before and after comparison of the Japanese coast between 5 September 2010 (left) and the 12 March 2011 (right). Data: Rapid Eye.
A small island obstructs the constant flow of the ice shelf on Queen Maud Land – it is the lighter area at the bottom left of the image. From September 2010 until it broke off, Iceberg A 62 was connected to the Fimbul Ice Shelf by a mere 800-metre-wide bridge. Two fissures in the ice from different sides of the bridge approached one another until the break occurred. The images transmitted by the radar satellite TerraSAR-X over a long period of time should enable researchers to achieve a better understanding of how icebergs calve. Until now, glaciologists have not been able to predict where and how much ice will break away each year.
The detailed picture of around 30 kilometres sent from the TerraSAR-X radar satellite shows the Antarctic Nimrod Glacier flowing around the Kon-Tiki Nunatak, a rock protruding through the ice sheet. It is even possible to pick out the fissures in the glacier’s main body.
This TanDEM-X image shows Salar de Uyuni, the largest salt flats in the world covering 10,000 square kilometres, located next to the volcanic region of the Atacama Desert. The blue to dark blue areas show the lowest lying parts of the salt flats. A trained eye can see the boundaries of rock deposits in the three-dimensional model. This information about landscape features helps us draw important conclusions about the origins and development of the area.
This image from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X satellite shows an area of the West African country of Gabon. The forest cover spans 210,000 square kilometres – 70 percent of the country's entire land area. The satellite image shows an uninhabited area around 60 kilometres south east of the capital, Libreville, in the vicinity of the Komo River delta. The flat surface of the river itself reflects the radar signals away from the satellite and appears as a dark area in the image. The forested area, on the other hand, has a rough texture when seen from space, which returns the radar signal to the TerraSAR-X at varying intensities. Such images enable scientists at the Friedrich Schiller University of Jena, to contribute to the United Nations' Global Forest Resources Assessment. This is the first time radar imaging from space has been used for this purpose.
The first bistatic radar image acquired by the twin satellites TanDEM-X and TerraSAR-X shows the Italian volcano Mount Etna, on the east coast of Sicily. On the left of the image, below the flank of the volcano, the city of Catania can be seen as a collection of bright points. This image, acquired while the satellites were orbiting at a distance of only 350 metres from one another, is the world's first to be made using such a close satellite formation.
TerraSAR-X mapped the oil-polluted area in the Gulf of Mexico in a series of images acquired on 9 July 2010. The environmental catastrophe started on 20 April 2010 when an explosion sank the Deepwater Horizon drilling rig and the shut-off valves on the wellhead could not be closed. The Artificial Barrier Island, an artificial island constructed by heaping dredged sand, situated to the east of the Chandeleur Islands, is easily recognisable in the TerraSAR-X imagery and it will soon be awash with spilled oil. “The imagery indicates that man-made constructions cannot offer much protection,” reports Susanne Lehner, team leader of radar oceanography at the DLR Remote Sensing Technology Institute (Institut für Methodik der Fernerkundung; IMF).
In the centre of this TanDEM-X image, ice floes can be seen in the sea ice off the coast of October Revolution Island. They project about 3-10 metres above the sea ice. The smooth structure on the left is the rocky coat of the island. Two glacier tongues that flow into the sea can be seen at the top of the image, to the left and right of a large boulder.
The geoglyphs show up as dark grooves in the ground in the vicinity of the small town of Palpa – which can be seen as a set of lighter dots in the picture. They can be seen on the radar images as a dark cross. The desert surface in this area normally consists of loose, rough stony ground, but in some areas this stony cover, coated with a black ‘desert lacquer’, is missing. In such areas we can see the lighter, finer under-surface. The stone heaps can be seen as a low wall at the edges of the clearings. The picture also clearly shows the town of Llipata to the south, as well as the Pan Americana highway, running as a narrow black line through green fields and the reddish stony desert. The dry bed of the Rio Viscas, through which water flows for only four to six weeks a year, runs almost parallel to the highway.
At the centre of the image is Moscow’s Sheremetyevo Airport, about 30 kilometres northwest of the city centre. Terminal One, to the north, was opened on 8 November 1959 and now serves mainly domestic flights. Terminal Two, in the south, was built for the Summer Olympic Games in 1980 by German companies following the design of the terminal at Hanover Airport. Today, it deals with international flights. The two runways are clearly visible. Because the flat concrete surfaces reflect the radar signals away from the satellite, the paved areas are shown as black lines. To the north of Moscow, there are major reservoirs such as the Pirogovskoye Reservoir and the Uchinskoye Reservoir.
Even the ups and downs of the waves in the Indian Ocean – coloured pale yellow on the image – are charted by TanDEM-X as it flies over at a speed of seven kilometres per second. The change in the waves at the entrance to the Diego Suarez Bay is clearly visible. The water in the bay itself, on the shore of which the provincial capital, Antsiranana, can be recognised, is very flat – in contrast to the undulating ocean – and reflects the radar signals from TanDEM-X more uniformly. The area of valleys to the south drains the volcanic cone of Ambre-Bobaomby into the Indian Ocean.
For the last four months, the German Aerospace Centre's (DLR) radar satellite, TerraSAR-X, has been imaging Mexico City from space. Amongst other things, the images show that even within this imaging period, the ground has sunk by as much as 10 centimetres in some places. Areas of the Mexican capital in which TerraSAR-X has recorded the greatest changes in ground level are coloured dark red. The green areas indicate those in which no change has been detected by the superposition of the radar images between 20 September 2009 and 30 January 2010. One of the reasons for this subsidence is the extraction of groundwater.To create this an image, the TerraSAR-X radar equipment was operated in a special 'wide-angle mode', the 'ScanSAR mode', in which a strip of land 100 kilometres wide can be depicted in one piece. As the radar is usually capable of 'illuminating' a significantly smaller area of land – about 30 kilometres across, a special trick has to be used in order to obtain a greater strip width. For this purpose, the radar beam is repeatedly swung from short to long range, so that, first of all, a small area measuring 25 x 3 kilometres is illuminated at close range. Then, more distant areas – offset by 25 kilometres – are illuminated, until four partial strips of the image have been scanned. The process is then repeated. Finally, a montage is produced from the individual scenes. The cost of the larger scene is a reduction in resolution from three metres to sixteen metres, but this causes no restrictions for numerous applications. Such a recording mode is made possible by the electronically steered phased-array antenna, which facilitates the rapid and inertia-free movement of the radar beam.The image of Mexico City was created by means of a refined scanning method known as Terrain Observation by Progressive Scans (TOPS) mode, which avoids the weakness of the classic ScanSAR – the varying illumination of individual surface patches. The result is an image without any variations in brightness.
This TerraSAR-X image shows a thunderstorm cell with unusually heavy rainfall off the Caribbean coast of Panama, visible across in the upper half of this image as a blurred area. The scene recorded here extends over an area of about 18 by 64 kilometres and was generated in dual-polarisation mode, a method that substantially increases the information content of an image. The colours are created by superimposing two separate images (red and green) of the same area taken simultaneously in this mode using two signals having different polarisation settings, together with a third image (blue) which is calculated from the difference between the original images. Now, the different reflection mechanisms become visible – the green colouration indicates a surface reflection, where the radar signal is being reflected straight back to the antenna. Red tones indicate a double reflection, and there is virtually no indication of this in the scene depicted here, since it occurs primarily in urban areas. Blue tones can be seen in the area of the thunderstorm cell, and are designated as 'volume scatter' because the signal is reflected back to the radar antenna by a multiplicity of individual raindrops and hailstones.
One of the applications of TerraSAR-X is mapping areas inundated by floods. Taken on 25 July 2007, the photo shows the towns of Gloucester (bottom) and Cheltenham (centre right) during the flood. Appearing quite dark, the areas flooded by the river Severn can be seen very clearly along the left side of the entire image. Even at this early point in time, the DLR Centre for Satellite-assisted Crisis Information (ZKI) at the German Remote Sensing Data Centre (DFD) in Oberpfaffenhofen used data transmitted by the TerraSAR-X satellite during the flood to develop maps to support relief forces on the spot.
DLR/Infoterra GmbH; date: July 25, 2007, 06:34 UTC; original resolution: 3 metres (image reduced); mode: StripMap mode; polarisation: HH.
On the east coast of the Antarctic Peninsula, lies the Larsen Ice Shelf – a sheet of ice which, floating on the sea and reaching far beyond the mainland, has made the headlines repeatedly in recent years because it keeps losing spectacular amounts of ice. The Larsen Ice Shelf consists of three parts that follow the east coast from north to south. It is thought that the ice shelves are disintegrating because temperatures in the region have been rising markedly in the last 50 years. As this removes a major obstacle to the movement of glaciers from the mainland to the open sea, scientists expect the flow rates of the mainland glaciers in the region to increase. TerraSAR-X permits more precise measuring of glacier flow rates, enabling scientists to forecast variations in the melt rates of the glaciers on the mainland and their impact on the environment with much greater precision.
DLR; date: June 26, 2007, 23:31 UTC; original resolution: 3 metres (reduced image); mode: StripMap mode; polarisation: VV.
Located in the middle of the Swabian Jura, the Nördlinger Ries is a flat, almost circular structure measuring about 20 kilometres in diameter. Gradually filled in and flattened by erosion, the crater was caused by the impact of a meteorite about 15 million years ago. At its centre stands the town of Nördlingen, surrounded by fields which are cultivated, as documented by the structures that radiate away from the city. In the centre of Nördlingen, the photograph shows the completely preserved ring wall that surrounds the old town. The data provided by TerraSAR-X permits studying microstructures in detail as well as analysing surface formations and land use. In this extensively cultivated region, also of great geological interest, the radar data supplied by TerraSAR-X will be an important source of information for analysis as well as for improving agricultural utilisation.
DLR; date: July 1, 2007, 23:00 UTC; original resolution: 1 metre (reduced image); mode: high resolution spotlight mode; polarisation: HH.
In the Mato Grosso province in the Brazilian southwest, no more than 2.5 million people live in a territory almost three times as large as the Federal Republic of Germany. The north of the province is dominated by the fringes of the Amazon rainforest where logging has been particularly extensive in recent years.Because of their different reflection characteristics, clearings appear in the radar image as rectangular, relatively dark zones within the otherwise homogeneous surface of the forest. Covering large areas with optical cameras mounted in satellites is especially problematic in the tropics as this region is frequently concealed by dense cloud layers.Under these circumstances, the radar instrument on board TerraSAR-X can make the most of its ability to generate detailed images. The valleys of the rivers that run through the area show up on the radar image even under their cover of vegetation.
DLR; date: July 8, 2007, 21:53 UTC; original resolution: 16 metres (reduced image); mode: ScanSAR mode; polarisation: HH .
This is a combination of two TerraSAR-X StripMap images of an area to the northwest of Munich measuring 30 by 20 kilometres, taken on 26 June and 7 July 2007.You can see Fürstenfeldbruck airport at the top centre and the Ampermoos north of Lake Ammersee in the lower left-hand corner.Taken at an interval of 11 days, the radar images show the area in exactly the same geometry - from the same angle of view. The colours indicate the intensity of radar backscatter at the time the two photographs were taken (red: first image, green: second image, blue: sum of both images). Intensity mainly depends on the roughness and humidity of the reflecting surfaces. A typical example is the very dark appearance of the relatively smooth runways at the airport.Such images are highly effective in tracking land surface changes caused, for instance, by harvesting grain fields.
DLR; date: June 26 and July 7, 2007, at 5:26 UTC each time; original resolution: 3 metres (reduced image); mode: StripMap mode; polarisation: VV and HH .
The colours in this TerraSAR-X radar image of the Kubitzer Bodden, north of Stralsund, tell us how strongly the radar beams emitted were scattered back by Earth's surface in each polarisation (red: HH, green: VV, blue: HH-VV). This permits the drawing of conclusions about various properties of the backscattering surfaces (e.g. roughness and humidity). Among other things, such information is used to identify different surfaces, such as forests, grain fields or sandbanks. Furthermore, the image yields valuable information about processes that go on above and on the water, such as roughness caused by wind. The stripes that are distinguishable in the Kubitzer Bodden are caused by so-called atmospheric boundary-layer rolls. Such image structures may serve to identify and derive high-resolution wind fields above the water. Aufnahmedatum: 7. Juli 2007, 5:24 UTC, Originalauflösung: 3 Meter (Bilddarstellung reduziert), Modus: Stripmap Mode, Polarisation: VV und HH
DLR; date: July 7, 2007, 5:24 UTC; original resolution: 3 metres (reduced image); mode: StripMap mode; polarisation: VV and HH.
In the centre of the Atacama desert near South America's west coast lies the world's largest open-cast copper mine. The mine was founded by the Guggenheim Brothers at the beginning of the 20th century; it was nationalised in the early seventies.The dominant feature of the image is an oval structure- the largest-ever depression in the Earth’s surface ever produced by human effort. On the bottom left margin of the pit lies the city of Chuquicamata, which is almost completely deserted because of the ever-expanding mining operations. Huge piles of mining debris appear as a monstrous fan shape (on the right). Depths vary between 600 and 1,000 metres.A high-resolution digital elevation model from new TerraSAR-X data will provide very accurate measurements of the exact depths.
DLR; date: July 1, 2007, 23:00 UTC; original resolution: 1 metre (reduced image); mode: High Resolution Spotlight Mode, polarisation: HH.
Mount Merapi on the island of Java (Indonesia) is known as one of the world's most dangerous volcanoes. The active volcano is situated north of the large conurbation of Yogyakarta, in the middle of a densely populated area.On the left of the image is Mount Merapi which is about 2900 metres high, next to Mount Merbabu on the right, which is assumed to be a dormant volcano.TerraSAR-X will, in the future, be able to detect even small movements of Earth's surface, thus assisting volcano analysis using interferometry measurements.
DLR; date: July 8, 2007, 10:51 UTC; original resolution: 3 metres (reduced image); mode: StripMap mode; polarisation: HH.
The upper part of this TerraSAR-X image of Sydney shows Botany Bay, located south of the airport. In the lower right section is Bate Bay. The rough sea rolling towards the coastline from the Tasman Sea is clearly visible. In the open water the waves have a length of about 150 metres. They become shorter as they enter shallower waters, and finally break as they hit the coastline. The image also shows so-called diffraction effects, which indicate a change in wave pitch (seen at the lower centre of the image). This effect is also related to the change in water depth. Two-dimensional images of wave fields in such a high resolution are of great interest for a variety of coastline management and shipping applications.
DLR; date: July 9, 2007, 19:27 UTC; original resolution: 3 metres (reduced image); mode: StripMap mode; polarisation: VV.
The pyramids of Giza are the only members of the Seven Wonders of the World that are still intact, while at the same time being the largest monument ever created. They are over 4500 years old, which makes them the best known and oldest man-made structures. The area shown is on the west bank of the Nile on the fringe of the Egyptian desert, about 20 kilometres from Cairo city centre. The metropolis has been sprawling out far into the desert, so that the pyramids are gradually becoming encircled by new residential developments. In the picture the three large pyramids can clearly be seen on the outskirts of the small town of Giza, with the Great Pyramid standing out as the most prominent one. The smaller pyramids come out equally well in the radar image. Structures in the desert sand can be seen to the south of the pyramids. The radar beam makes it possible to recognise structures below ground level under certain conditions, especially in arid areas with a loose type of soil. This opens up new archaeological options and constitutes yet another application of TerraSAR-X data.
DLR; date: July 2, 2007, 03:47 UTC; original resolution: 1 metre (reduced image); mode: High Resolution Spotlight Mode; polarisation: HH.
The Strait of Gibraltar, the gateway between the Atlantic Ocean and the Mediterranean Sea, can be seen in the centre of the image. Numerous bright spots represent ships, documenting busy traffic in the Strait. Gibraltar is located in the north, Morocco on the opposite side in the south. Also on the Spanish side a peninsula extends into the Atlantic, a piece of mainland near the city of Tarifa, which represents the southernmost point of mainland Europe.TerraSAR-X data will be available in the near future for monitoring marine traffic as well as for spotting oil spills in the oceans. TerraSAR-X will also be able to determine the speed of ocean currents, thus assisting oceanographic research.
DLR; date: July 9, 2007, 06:29 UTC; original resolution: 3 metres (reduced image); mode: StripMap mode; polarisation: HH.
TerraSAR-X can operate in a new mapping mode that enables it to detect moving objects and measure their speed. This capability is used to determine the speed of ocean currents but also to record the speed of ships or motor vehicles.This image shows the A1 highway (Autostrada del Sole). The section is located about 100 kilometres southeast of Rome.This radar imaging technique is based on the Doppler effect, so the vehicles appear 'offset' from the highway. The extent of the lateral deviation is a measure for a vehicle’s speed. Using this new mode, TerraSAR-X will detect vehicles off the road, and determine their distance from the road. The red squares mark the vehicles, the coloured triangles indicate their current position, with the colour indicating their speed. These data will, in future, be used by transportation research teams who will integrate these extensive pictures of moving traffic into their traffic models along with locally obtained sensor data, to improve their capability to predict congestions and to manage the flow of traffic.This will be particularly useful in disaster management and mass events, in which current traffic models may fail. The identification of individual vehicles is not possible with this technology, but also unnecessary for traffic research.
The image shows a section of Las Vegas close to Boulder City. On the right is the high-resolution TerraSAR-X elevation model; for comparison, the elevation model on the left is based on data currently available worldwide, from the Shuttle Radar Topography Mission (SRTM), to which DLR contributed. It dates back to the year 2000.With its radar technology, TerraSAR-X can measure the surface of Earth with extreme accuracy and provide data for ultra high resolution digital terrain models. However, this requires at least two satellite overflights to ensure that the satellite can image the terrain from two different angles. If either rain or wind alter the surface reflectance between two successive passes of the satellite, the quality of the resulting terrain model will be affected.Hence, for the time being, dry areas are the preferred areas for testing the imaging function and elevation derivation, given their low rate of surface change. This limitation will disappear in the future once the projected Tandem-X Mission is operational. This mission will involve an almost identical satellite that will be shot into a quasi-parallel orbit. The two satellites together will work as a tandem, both imaging the same area for an immediate derivation of digital elevation models with a very high spatial resolution.
DLR; date: July 7, 2007; original resolution: 1 metre (reduced image); mode: Spotlight Mode; polarisation: VV.
The ring structure shown in this image is located in Ouadane in Mauritania. It has a diameter of about 45 kilometres. Astronauts have been drawn to this structure ever since the beginning of spaceflight. Since it is easily identified from space it has served astronauts and cosmonauts on their orbital missions as an unmistakable landmark. The ring consists of limestones, dolomites and brecchias from the late Proterozoic to Ordovician eras (aged about 0.6 to 0.5 billion years) that were centrally uplifted and subsequently eroded. The question as to the structure’s origin, which is widely thought to have been originally a meteorite crater, has yet to be answered. Analysis of the magnatites which prevail in the centre of the formation suggest that the structure is the expression of a cretaceous alkaline complex. Although the exposed layers have formed a shallow ridge which, in many parts, is no more than a few metres high, the structure can be excellently identified and mapped in a radar image thanks to its surface properties.
DLR; date: July 8, 2007, 18:53 UTC; original resolution: 16 metres (reduced image); mode: ScanSAR Mode; polarisation: VV.
The near-circular, conical peak of Mount Egmont on New Zealand’s North Island presents itself in full glory. It is assumed that the volcano has had this shape only for the last 10,000 years, and the same goes for its 2518 metre height. Lava flows from earlier outbreaks have covered a major part of the surroundings, stretching across 25 kilometres towards the ocean, forming a ring-shaped plain.The Maori people call this mountain 'Taranaki', which means 'without vegetation'.Only a few thousand years ago, the lower plains were completely covered by dense rain forests. Today, the only forests left are those on the slopes of Taranaki in the Egmont National Park, which stands out from the surrounding intensively used farming and pasture land as if drawn with a compass.It has a number of snow fields but no glaciers on its peak. Often in the summer season, the peak is completely ice free, while in the winter, skiing is possible on Manganui’s own ski-field.
DLR; date: July 15, 2007, 07:07 UTC; original resolution: 3 metres (reduced image); mode: StripMap mode; polarisation: VV.
To prepare this photograph, three images of TerraSAR-X were superimposed. The individual imgaes were obtained on 22, 24 and 27 October 2007. The areas photographed with time intervals appear in blue and green - in particular the areas affected by the tides of the Wadden Sea.
TerraSAR-x StripMap product, 30 x 55 kilometres, as an example of EEC projection. It shows the Upsala Glacier in Patagonia, Argentina.
This image of flooding in Mexico was obtained in November 2007.