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Approximately 290 billion years ago, two big asteroids collided with the Earth. The craters are still visible - to astronauts in the orbit, the lakes inside the craters are popular subjects for photographs. The crater lakes' diameter is 26 resp. 36 kilometres.

 

At the time of collision, the area had been at the equator, but plate tectonics lead to a northward shift. Nowadays, the crater lakes are in Qebec, Canada. During the ice ages, the landscape was grounded by glaciers. By the time they had melted, much of the cracks in the bare rocks filled with the left-over water. Thus the network of linear rivers and lakes was formed.

 

Location: Quebec, Kanada

Picture taken on June 29, 2013

Sensor: Landsat 8 - OLI

NASA Earth Observatory, Link: http://earthobservatory.nasa.gov/

The world from the view of a satellite.

 

Picture taken on July 11, 2005

Sensor: Terra MODIS

NASA (Marit Jentoft-Nilsen, Robert Simmon); Link: http://earthobservatory.nasa.gov

The Ouachita Mountains in west central USA are more than 300 million years old. Today, they are weather-beaten and noticeably  eroded. The remains that you can see in this image were once a part of a much more extensive mountain range that is believed to have spanned from Texas to Southeast Canada. The image combined information from the wavelength ranges of infrared, red and green. The complex shape of the mountains is characterised by a pattern of longish, folded formations. Between the mountain slopes, you can see water, vegetation, cities and streets.

 

Location: USA
Picture taken on November 13, 2002
Sensor: Terra ASTER
Band combination: R/G/IR

NASA/GSFC (Jesse Allen, Robert Simmon); Link: http://earthobservatory.nasa.gov

On April 20, 2010 the oil drilling rig “Deepwater Horizon” leased by BP exploded in the Gulf of Mexico. This accident resulted in one of the most devastating natural disasters of our time: Over months, more than several hundred millions of litres of oil streamed into the sea. As the catastrophe unfolded, the oil also reached the Mississippi Delta. There is reason to believe that a part of the spill reached the world-spanning sea currents as well and thus has been spreading globally ever since. The oil spill that can be seen in the image only shows a small part of the scope of the disaster.

 

Location: Gulf of Mexico
Picture taken on April 25, 2010
Sensor: Aqua MODIS

 

 

NASA/GSFC; Link: http://rapidfire.sci.gsfc.nasa.gov

In comparing these two images, you get an idea of the rapid growth of Las Vegas, Nevada, between 1973 and 2002. Las Vegas is one of the fastest-growing US cities. Its high immigration rate and its areal extent have a negative effect on the water budget of this arid region. In order to solve this problem, politicians intervened: It is now forbidden to build new swimming pools, fountains must be operated using wastewater and the lawn can only be watered at certain days of the week.

 

Location: Las Vegas, USA
Pictures taken on June 10, 1973 and June 10, 2002
Sensors: Landsat 5 and Landsat 7

 

 

USGS; Link: http://earthexplorer.usgs.gov/

Approximately 80 per cent of the global water consumption can be ascribed to irrigation farming. In this false-colour image from above Kansas, red stands for healthy vegetation while farmland sticks out due to its conventional and circular irrigation. The so-called centre-pivot irrigation is common in dry areas with a large land-use management. Its characteristic shape is clearly visible from space.

 

Location: Kansas, USA
Picture taken on September 26, 2010
Sensor: Terra ASTER
Band combination: Vis/NIR

USGS; Link: http://earthexplorer.usgs.gov/

The geological history of the Grand Staircase-Escalante National Monument in Utah, USA, goes back more than 275 million years. This image shows a central part of the basin. The dendritic relief reveals a myriad of canyons. The erosions was caused by rivers millions of years ago. In the past, precipitation in this region was considerably heavier than it is today. Due to tectonic uplift, the area has dried out more and more.

 

Location: Utah, USA

Picture taken on May 15, 2005

Sensor: EO-1 - ALI

 

 

NASA (Jesse Allen, Robert Simmon); Link: http://earthobservatory.nasa.gov

Along highway 20 from Idaho Falls heading toward Yellowstone National Park, green and golden fields dominate the fertile plain of the Snake River. The circular areas indicate extensively irrigated farmland. The white dunes developed towards the end of the last ice age approximately 10 000 years ago when the global climate started to become warmer and drier. Lakes and rivers dried up leaving fine sand behind. Continuous winds from the south west blew the sand in northeasterly direction, passing lava fields which are quite dark in the picture.

 

Location: Idaho, USA
Picture taken on September 9, 2010
Sensor: EO-1 – ALI
Band combination: R/ G/ B

 

NASA (Jesse Allen, Robert Simmon); Link: http://earthobservatory.nasa.gov

In the middle of this false-colour image, you can see the tongue of the Malaspina glacier. The glacier makes its way from the mountains in the north and is separated from the sea by its terminal moraine as can be seen in the lower part of the picture. Without the moraine or in the case of a sea-level rise, the glacier would come in contact with the warmer sea water and it would retreat more quickly than it does now. Satellite images and measurements on the ground show that most glaciers in Alaska are getting thinner and that only a few dozen are gaining in ice mass.

 

Location: Alaska
Picture taken on April 27, 2003
Sensor: Landsat 7 ETM+
Band combination: B/ G/ NIR

USGS; Link: http://www.usgs.gov

This image shows the two twin islands in the southern part of Hudson Bay (North and South Twin Island). In spring, the ice of Hudson Bay clears, usually leaving the south-western part, in which the two islands are located, as the last area with a closed ice sheet. Climatologists are worried about Arctic melting processes: In recent years, there have been more and more ice-free phases, signalling an increase in climate warming.

 

Location: Hudson Bay, Canada
Picture taken on February 20, 2002
Sensor: Landsat ETM+
Band combination: MIR/NIR

USGS; Link: http://earthexplorer.usgs.gov/

These four images show the region surrounding San Francisco Bay, USA, with different band combinations.
Top left in the picture, the band combination of visible and reflected infrared light results in a red depiction of vegetation and a grey depiction of urban areas. Light blue indicates sediment in the bays. Top right in the picture, the band combination of short-wave infrared highlights the different soils and rocks of the mountainous region. Bottom left in the picture, multispectral thermal bands emphasise the differences of the urban surfaces through different colouring. Bottom right in the picture, you can see how different thermal bands can visualise water temperature: Warm water is depicted in white, yellow and red; colder water is depicted in blue. In the right upper corner, you can see Suisun Bay directly feeding on the cold Sacramento River. If the water flows through San Pablo and San Francisco Bay while making its way towards the Pacific Ocean, it heats up.

 

Location: USA, San Francisco
Picture taken on March 3, 2000
Sensor: Terra ASTER
Band combination: diverse, see above 

 

 

NASA/GSFC; Link: http://visibleearth.nasa.gov

This false colour image shows farms alongside the Buffalo River in the US state Minnesota. Among other things, the term “precision farming” refers to the monitoring of plant health with the help of satellite images. Due to the depiction in the infrared spectrum, the farmers are provided with a lot of information about their fields.
Yellow areas indicate cultures that have been attacked by vermin, shades of red stand for healthy vegetation and black signals that there is too much water in the ground. What is more, weeds and hail damage can be detected by means of remote sensing as well.

 

Location: Minnesota, USA

Picture taken on September 10, 2009

Sensor: Landsat 5 – TM

Band combination: G/ R/ NIR

 

 

NASA (Jesse Allen); USGS; Link: http://earthobservatory.nasa.gov

In this false colour image, the Susitna Glacier in Alaska seems like a river fed by its influent streams and flowing towards the valley. Due to the depiction in false colour, the vegetation in this picture is bright red, the pure surface of the ice is light blue and white, ice covered with sediment (medial and lateral moraines) is brown and water is dark blue. The dynamics of the glacier are most striking in the middle of the picture where you can see a tributary glacier pushing its ice masses sideways into the trunk glacier.

 

Location: Alaska

Picture taken on August 27, 2009

Sensor: Terra ASTER

Band combination: G/ R/ IR

 

 

NASA/GSFC (Jesse Allen, Robert Simmon)