"The Earth as a Work of Art!"

Special photographic section

This issue, produced in cooperation with the Helmholtz Association, combines Art and Science in a series of surprising satellite images. A world tour in technicolour…

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The Betsiboka Estuary, Madagascar

The port of Mahajanga on the northwest coast of Madagascar is becoming increasingly silted because the inland forests are being cut down. The wood is needed as fuel, while the cleared forest areas serve as farmland. However, without the protective function of the trees, the heavy monsoon rains wash away the top soil layer. New paddy fields silt up with sediment and the soil is washed into the River Betsiboka and from there into the Bay of Mahajanga, where bush and brushwood islets form (red and green) and obstruct shipping.

Source: Top: USGS, EROS Data Center Bottom: NASA

Satellite: Landsat-7 ETM+

Date: 2000

Altitude: 705 km

Technique: Visible and near-infrared light, false-colour image

The Altun Shan Mountains, China

The image shows the bare mountains on the southern edge of the extremely arid Altun Shan Mountains in North China. The green spots in the top right-hand corner indicate the presence of metalliferous rock. The large ochre-coloured surface is a dried-out salt lake. Salinised soils lie to the left and right in their bluish colour. The black line that extends across the image is a road. At the upper edge, the salt lake can be recognised as a white island. The People’s Republic of China uses such images to geologically map the country.

Source Top: China RSGS

Bottom: NASA

Satellite: Landsat-TM

Date: 1995/1996

Altitude 705 km

Technique: Visible and infrared light

Ocean Eddies and Currents

The eddies and currents that form in oceans can only be made visible by satellite images. The colour indicates the presence of tiny chlorophyll-containing algae (plankton) - the staple diet for many fish. The higher the temperature and the chlorophyll level, the higher the plankton concentration (red). Areas with few nutrients (blue) are colder and contain less food for the fish. The black areas are the mainland (top) or smaller islands (bottom right). Data like this provide fisheries with information on where rich fishing grounds lie.

Source: NASDA

Satellite: IKONOS

Date: 1998

Altitude: 797 km

Technique: Ocean colour in the visible spectrum combined with various infrared areas

Lake Garda, Italy

Italy’s largest lake - Lake Garda (Lago di Garda) - was formed by glaciers during the last ice age. The peninsula at the southern end of the lake accommodates the town of Sirmione, Roman ruins, and the famous Scaliger Castle (see left-hand side). Satellites see more than the human eye: this image shows only the lake because its surroundings have been masked out. Digital image processing has been used to enhance the contrast so that differences in sediment concentration are clear, allowing conclusions to be made on the quality of the water.

Source: NASA, DLR

Satellite: Terra/ASTER

Date: 21 July 2001

Altitude: 705 km

Technique: Thermal image highly contrast-enhanced

Bend of the Spree, and City Centre, Berlin

The face of the German capital has changed substantially since the Iron Curtain fell. From 1961, the Berlin Wall ran in a north-south direction through the middle of this picture, until the people of East Germany tore down the German-German border in Autumn 1989. A new modern centre has developed around the Potsdamer Platz. The distinctive roof of the Sony Center and Berlin’s new Central Station are clearly recognisable, even from an altitude of 680 km. The Reichstag and Brandenburg Gate stand in the centre of the image.

Source: European Space Imaging, DLR

Satellite: IKONOS

Date: 2 September 2005

Altitude: 681 km

Technique: True-colour image

Madrid, Spain

Madrid boasts a green heart, the Parque del Retiro, which appears red in the false-colour image. Parks and particularly large, open green spaces act like air conditioners for surrounding districts during the summer heat. These cool-air islands can be very easily observed with satellites and then taken into account when planning new residential areas. The clearly recognisable road infrastructure reveals the various phases of urban development, from the narrow jumble of old town alleys via the linear chequered pattern of later ages through to major arterial roads and motorways.

Source: DLR, NASA

Satellite: Terra/ASTER

Altitude: 705 km

Technique: False-colour image

Kaladan Delta, Myanmar/Burma

Enormous mangrove forests grow in the Kaladan Delta in Myanmar/ Burma - depicted here in dark green. The light green areas are swamps, while the dark dots represent cleared islands. The land is often flooded during the monsoon because it lies just a few metres above sea level and therefore is constantly changing. Such images do more than just produce and up

Date: maps. The data aid important decision-making. Where can a school be built so that it is not flooded during the next monsoon?

Source: DLR

Satellite: SIR-C/X-SAR (Space Shuttle)

Date: 1994

Altitude 450 km

Technique: Radar (vegetation coloured green)

Escondida: The World’s Largest Mine, Chile

Right in the heart of the Atacama Desert in northern Chile and at a height of 3 050 m lies the world’s largest copper, gold and silver mine. This open-cast mine produces 127 000 tonnes of ore every day. The image on the right shows the area as we would see it from a plane with our naked eye. But the mine looks completely different in short-wave infrared light (colour image). This makes it possible to identify different kinds of rock. Rocks that contain copper show up through their green colour. Mined areas are shown in a reddish-beige hue.

Source: NASA

Satellite: Terra ASTER

Date: 23 April 2000

Altitude: 705 km

Technique: Short-wave infrared light contrasted to visible light with near-infrared light

Namib Desert, Namibia

This radar image shows the Namib Desert at Diaz Point near Lüderitz. Only 10 to 20 mm of rainfall per year are recorded in this region. The violet areas are sand dunes that extend down to the coast. The orange area is the Atlantic. The narrow band between land and ocean marks the beach. The top right-hand corner shows rocks protruding from the sand. Images like these are used to discover geological structures beneath the desert sand, such as subterranean rivers.

Source: NASA

Satellite: SIR-C/X-SAR

Date: 7 November 1996

Altitude: 450 km

Technique: Radar

Bathymetry of the North Atlantic

Satellite technology is capable of reconstructing the processes that take place beneath the ocean surface and decisively shape our continents, as well as the relief of the ocean floor and its history. This image shows the North Atlantic with the volcanically extremely active Iceland lying on a central-oceanic ridge. Lava pushes to the surface along the submarine mountain ridge and in doing so pushes the continental plates apart. This is how Europe and America began to drift apart 120 million years ago, a process that continued for 80 million years.

Source: DLR, GFZ, USGS

Satellite: ERS-1 and bathymetric measurements

Altitude: 782 km

Technique: Bathymetric model shown in perspective

Storm Front Lothar/NOAA-14 AVHRR

The dynamics and power of a low-pressure system are clearly visible here. Around Christmas 1999, storm front Lothar raced across France, Switzerland and Germany. Around 100 people died, more than 100 million trees were uprooted. Insured damage value: some € 3 billion. Satellite technology allows ever more precise forecasting and so continually optimizes measures to protect against weather disasters. Geostationary satellites like Meteosat or NOAA-14 AVHRR keep a wary eye open for us on the weather on Earth and so provide a basis for early warning systems.

Source: DLR

Satellite: NOAA-14 AVHRR

Date: 25 December 1999

Altitude: 833 km

Technique: Thermal infrared

The “Bull’s Eye” - a Landmark for Astronauts, Mauritania

With a diameter of just under 50 km, the unmistakable Bull’s Eye - actually the “Richat Structure” - is an important landmark for Space Shuttles. Once they have flown over it, the astronauts know they will soon be landing at Cape Canaveral. Initially, researchers thought the structure was the result of a meteorite impact. Today, they think it is a plutonite, a magna flow that cooled and solidified under the earth’s surface. Surface soil has been washed away by the rain and the hard rock now protrudes as a plateau.

Source: USGS, EROS Data Center

Satellite: Landsat-7 ETM+

Date: 7 October 2000

Altitude: 705 km

Technique: The b/w channel combined with colour and infrared channels

The Ngorongoro Crater, Tanzania

This image was shot over the Serengeti National Park. The collapsed crater - a caldera - of the Ngorongoro Volcano can be seen in the centre of the picture. The Ngorongoro Game Reserve lies in this caldera. The lakes have been coloured dark blue, while hills, mountains and exposed rocks are shown in brown. The dry vegetation of the lower-lying savannah is given a light blue hue. It’s more humid in the crater and so there is also more foliage, which is shown green. Pictures like these are used by the nature park administrators to monitor how the vegetation is developing in the park.

Source: GAF

Satellite: Landsat TM

Date: August 1995

Altitude: 705 km

Technique: Visible spectral range combined with infrared channels

Agriculture in Kansas, USA

The image shows meadows and fields. A centre-pivot sprinkler arm up to 400 m long rotates to irrigate the farmland. The colours indicate how moist the soil is and also whether cereal or vegetable crops are being cultivated. Green, irrigated wheat fields probably lie where the infrared light reflects most (red circles), while brownish circles depict fallow fields or areas where the seeds have not yet sprouted. Green circles are mainly meadows and pastures. Such images make it possible to estimate the expected harvest yield for the year.

Source: USGS, EROS Data Center

Satellite: Landsat-7 ETM+

Date: 1 November 2001

Altitude: 705 km

Technique: Combination of various spectral bands in the visible and infrared spectrum

Virtual Panorama - the Alpine Arc, in Perspective

Many different sources, including satellite-based measurements, delivered data for this digital elevation model that displays the whole Alpine Arc with consistent quality. Each height gets a colour, ranging from dark green (lowlands) via light green, yellow, ochre, brown through to heights of around 3 000 m shown in dark brown. Heights above 3 000 m or so appear white. Drawn in perspective and artificially lit, the pseudocoloured elevation model becomes more three-dimensional through the interplay of light and shadow.

Source: DLR, ESA

Satellite: ERS-1, ERS-2, SRTM

Date: ERS: 1995-1996; SRTM: 2000

Altitude: 782 km or approx. 300 km

Technique: Computer generated perspective view from pseudocoloured digital elevations model

Farming in Castilla-La Mancha, Spain

Despite difficult climatic conditions, intensive farming has developed to the south-west of Albacete, in the Spanish province of Castilla-La Mancha. The main crop consists of cereals. Irrigated fields are seen as circles made by a centre-pivoted irrigation system. The red colour is produced by using false colours - the more intensive the red, the healthier the vegetation. At one metre per pixel at ground level, the image’s resolution is extremely high for a satellite picture.

Source: European Space Imaging, DLR

Satellite: IKONOS

Altitude: 681 km

Technique: Near-infrared, false colour image

The Earth at Night

The sleepless planet - oceans of light wherever heavily built-up areas lie. Yet, brightness does not necessarily reflect population density. India and China with their billions of people are relatively dark. By contrast, the United States is wasteful in its use of electric light. Even sparsely populated areas are relatively bright. Originally, this kind of earth observation was used for a completely different purpose. During the Cold War, the United States used such imaging methods to monitor night-time missile launches.

Source: DLR, NASA

Satellite: DMSP OLS

Altitude: 833 km

Technique: Combination of visible and thermal infrared light, underlayed with a world map

The Lambert Glacier, Antarctica

The Lambert Glacier in East Antarctica is the world’s largest. It is more than 400 km long and just under 50 km wide. An icefall measuring 400 m from top to bottom feeds the glacier (upper half of the picture). At the coast, the glacier pushes out to the sea. The shelf ice is thus mainly fresh water. The giant icebergs that drift in the polar seas are pieces that have broken away from such glaciers. Red tones in the lower half of the image show the cliffs that protrude from the glacier.

Source: USGS, EROS Data Center

Satellite: Landsat-7 ETM+

Date: 2 December 2000

Altitude: 705 km

Technique: Visible light

Glacial Retreat, Chile

This false-colour image shows the great San Quintin Glacier in southern Chile. The ice extends down to the lowlands, the flanking vegetation is shown red. The glacial tongue flows into a lake (left-hand edge), surrounded by the terminal moraine that the glacier pushes ahead of it. Mountain glaciers respond much more quickly to temperature changes than polar glaciers. Some glaciers in the Andes have already become much smaller. The centre of the image shows an area that was still largely covered by ice in 1994.

Source: NASA

Satellite: Terra ASTER

Date: 2 May 2000

Altitude: 705 km

Clear View across Europe

The clouds were removed from a satellite image acquired by Europe’s Meteosat and superimposed on to a picture of Europe without clouds. This produced a very realistic colour impression that could not have been achieved in such detail with a “standard” Meteosat image. Meteosat data play a key role in weather forecasting and long-term climate and atmosphere observation. The satellite measures the temperature of the earth surface and the amount of water vapour in the atmosphere and transmits the data once every 15 minutes.

Source: EUMETSAT, DLR/Planetary Visions

Satellite: METEOSAT/MODIS

Date: June 2005

Altitude: 36 000 km and 705 km

Technique: Image composed of various sets of satellite data

The Great Salt Desert: Dasht-e Kavir, Iran

The Dasht-e Kavir lies to the south-east of Tehran and is, with an area of 55 000 km2, one of Earth’s largest salt deserts. The wind has blown away the sand and exposed the ground rock made up of various layers of deposited clay - shown brown here. The blue shades reveal salt lakes or swamps with a salt crust. The concentric circles show that the water evaporated very slowly here after earlier floods. Images like these are used to produce satellite maps of previously unsurveyed regions.

Source: USGS, EROS Data Center

Satellite: Landsat-7 ETM+

Date: 24 October 2000

Altitude: 705 km

Technique: Visible light (red and green) and infrared

Traces of War in the Persian Gulf, Iraq/Iran

Traces of military conflicts - viewed from space. This image was shot long after the Iraq-Iran war (1980 to 1988). The River Schatt-el-Arab runs along the left-hand side and forms the border between Iraq and Iran. Fortified walls and dams line up along the border in the top right-hand corner. The Iraqis built these ramparts in the swamplands for their artillery. At the same time, they flooded the resulting ditches for further military defence. Images like these were useful when reestablishing farming in the war zone.

Source: USGS, EROS Data Center

Satellite: Landsat-7 ETM+

Date: 24 January 2001

Altitude: 705 km

Technique: A b/w photo combined with colour and infrared channels

Klyuchevskaya Sopka, Russia

On the sparsely populated Russian Kamchatka peninsula stands one of the world’s most active volcanoes. Klyuchevskaya Sopka is one of around 500 active volcanoes in the Pacific Ring of Fire. The Pacific and Eurasian plates collide under Kamchatka. The picture was taken after the eruptions of 30 September 1994. Red areas represent solidified lava. The mud flows of melted snow and volcanic ash appear greenish-blue. These could threaten fields and settlements down in the valley.

Source: NASA

Satellite: SIR-C/X-SAR (Space Shuttle)

Date: 5 octobre 1994

Altitude: 450 km

Technique: Radar, 4 750 m

The Tien Shan Mountains, China

This part of northwest China is sparsely populated and was surveyed in a special mission during which two satellites flew exactly the same route in tandem exactly 40 minutes apart. This dual survey at such a short interval produced very precise elevation data on the region. The colours correspond with those of conventional maps: brown for hills and mountains, green for lowlands. The three-dimensional effect is achieved by additionally integrating shadows. Precision maps or elevation models of such remote areas are hardly conceivable without satellite technology.

Source: DLR, ESA

Satellite: ERS-1 & -2

Date: 1999

Altitude: 785 km

Technique: Radar

Farming on the Edge of the Desert, Saudi Arabia

Arid regions like this on the edge of the Saudi Arabian Desert can only be farmed with intensive irrigation. The two dark circles on the left-hand edge are irrigated fields. Groundwater pumped to the surface is distributed via irrigation systems. The area coloured in shades of red and orange is a dune landscape. On the right, the mountain ranges with their exposed rock have been coloured blue. Such images help geologists search for groundwater in arid zones. They believe that they might be able to find water beneath longdried- out river beds (wadis) that have meanwhile filled with sand.

Source: DLR

Satellite: MOMS

Date: December 1996

Altitude: 700 km

Technique: Visible and infrared light

Mayon, Philippines

Mayon is the most active volcano on the Philippines - it has erupted no less than 47 times since 1616. The image was shot from a radar satellite and shows characteristic coloured stripes. These correspond with the elevation lines on maps and accurately depict the contour lines to within just a few metres. The closer the coloured lines, the steeper the mountain incline. Any changes in height are a sure sign of activity within the volcano.

Source: ACRoRS, Bangkok Thailand, ESA

Satellite: ERS-1

Altitude: 785 km

Technique: Radar interferometry


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