The satellite ENVISAT
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ENVISAT (Environment Satellite) is a satellite dedicated to scrolling monitoring of land resources and responsible for acquiring high-resolution images of the atmosphere, land and ice, in a wide range of spectral bands. High resolution requested requires the adoption of small swaths requiring several days of scanning for a detailed mapping of the surface.
ENVISAT embarks on this, ten instruments that can operate simultaneously with the imaging sensor.
The Envisat mission has been designed by the European Space Agency (ESA).
The data produced by Envisat are used in scientific research on Earth and the monitoring of environmental and climatic changes.
The launch of Envisat was conducted on 01.03.2002 from Kourou in Guiana by an Ariane 5 rocket (Flight 145). The mission was to continue for an operational life of 5 years but was extended until 2013.
This very large satellite has a mass of 8200 kg including 2050 kg of instruments and 300 kg of propellant for a space requiring 10 m x 4 m x 4 m.
In orbit, ENVISAT dimensions are 26 m x 10 m x 4 m.
The solar array's dimensions 14m x 5m and can have a power of 6.6 kilowatts stored in 8-nickel cadmium batteries 40 Ah each.
This study provides insight into the many changes and upheavals in progress (El Niño, the warming of the planet, the hole in the ozone...), results of a complex between human activities and natural processes.
Look behind these changes and anticipate their consequences, represents a major concern for many governments and international organizations.
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|Launch||March 1, 2002|
|Masse||8 211 kg|
|Orbit||circular, helio synchrone|
|Inclination||98,6°|| || |
Image: ENVISAT evolving at an average altitude of 800 km on a nearly circular orbit inclined 98 ° to the equatorial plane. Its orbital period is 101 minutes and its orbital cycle is 35 days.
Caspian Sea as seen by Envisat
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The Caspian Sea is classified as the largest lake or the smallest sea in the world with a total area of 371 000 square kilometers.
It measures 1 200 km from north to south, almost tidal Caspian Sea fills a deep depression between Europe and Asia, its water level is around 28 meters lower than the global sea level. Remains of ancient Tethys Sea, the Caspian Sea is bordered by Russia and Kazakhstan to the north, Azerbaijan to the west, Turkmenistan to the east and south Iran.
The maximum depth of the Caspian Sea is 980 meters. The Caspian basin is rich in oil fields (oil center of Baku, capital of Azerbaijan).
River Uzboy (Uzboi) that flowed into the Caspian Sea has dried following the catastrophic drought of the 17th century. Today it is an intermittent stream.
The mountain Iranian Alborz (Elburz) is adjacent to the southern plains (Gilan-Mazanderan) and includes the highest peak of Iran.
The inactive volcano Damavand of 5 604 meters is the highest mountain in western Asia to the Middle East.
Damavand is located at the south end on the photograph, one can see a little snow job. Iranian capital Tehran is 100 km from the shores of the Caspian barely visible in the gray area in the third picture on the north-west, south of the green.
The Alborz mountain range acts as a barrier for the clouds, which explains the contrast between the fertile northern plains and desert to the south.
Image: Photograph taken by the spectrometer (MERIS) instrument Envisat October 3, 2005 (image covers an area of 672 672 km).
Region around the island of Samoylov
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This image shows the region around Samoylov Island, located in the Lena River Delta on the coast of the Laptev Sea, Northern Siberia.
The small island of Samoylov pear-shaped bottom of the image is one of the 1,500 islands of the Lena River Delta. The Delta covers an area of approximately 32 000 square kilometers and completed the long course of 4400 km, from the Lena River.
It is a haven for wildlife where the Arctic tundra becomes frozen during the five summer months in moist and fertile land. This fertile land is home to many migratory birds and supports diverse populations of fish and various marine mammals.
Soils are markers of the dynamics of geomorphological systems in which different levels can be distinguished in this image.
The upper image is an area of tundra with numerous ponds and small lakes. The lower part is the accumulation of fluvial deposits of permafrost, dark green on the image.
All terraces suffer erosion of riverbanks.
This region is the subject of investigations and observations Germano Russia regarding the biology, Earth science, ecology and environmental change.
The German Alfred Wegener Institute for Polar and Marine Research (Russian Lena Delta Reserve), has placed an ecological station on the island Samoylov and will consider placing this site on a permanent observatory of the environment.
Image: Photography of islands around the region Samoylov taken July 5, 2005 by the Compact High Resolution Imaging Spectrometer (CHRIS).
Temperatures of the Atlantic
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The oceans, with an average depth of 3700 to 3800 meters, covering 70.8% of the surface of the Earth about 361 million km2.
Their total volume reached 1.37 billion km3 of water.
Envisat's Advanced Along Track Scanning Radiometer (AATSR) continuously monitors the temperature of sea surface with an accuracy of few tenths of a degree.
The radiometer satellite captures the infrared emission of the first millimeters of the sea
This issue is related to temperature by the law of black body.
We deduce the exact temperature of sea surface.
Satellite data are increasingly used over other temperature readings (buoys, boats,...), because of their greater accuracy and coverage.
Image: Image of Atlantic misrepresentation of color, cold blue waters and red the warmest.
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Iceland under the snow from October 2008
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Envisat's Advanced Along Track Scanning Radiometer (AATSR), shows Iceland covered with the first snow of the winter of 2008.
Iceland (capital Reykjavik) is located in the North Atlantic Ocean south of the Arctic Circle, is the most western European countries.
Seen in this image, the largest glacier in Europe, Vatnajokull Glacier (8,000 km ² and 900 m thick).
The green border, which runs along the south and west dimensions of Iceland shows the presence of phytoplankton, present only in the surface layers of the oceans. It was there that accomplishes photosynthesis by absorbing minerals and carbon (as CO2) and releases oxygen under the influence of light.
Image: Image of the largest glacier in Europe, Vatnajokull Glacier, it was taken October 4, 2008 by camera MERIS (Medium Resolution Imaging Spectrometer) Envisat high resolution (source ESA).
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The space satellite Envisat's Advanced Along Track Scanning Radiometer (AATSR), shows the confluence of the Rio Negro and Solimões downstream from Manaus, Brazil, in the Amazon basin.
The Amazon is the longest and most powerful river in the world flows slowly between the 5th parallel north and 20th parallel south. The river has its source in the Peruvian Andes to the west of Lake Titicaca and empties into the Atlantic Ocean at the equator after crossing Peru and Brazil.
The Amazon is the source of 18% of the total volume of fresh water discharged into the world's oceans and its hydrographic network of more than 1000 rivers with the Rio Negro and Solimões.
The Rio Negro is named after the color of decomposed plant that carries throughout his career (Black River on the photo). The Solimões transports him to 1600 km, sand, mud and silt that color the water a yellowish color.
The forest of the Amazon is the largest rainforest in the world, it absorbs a huge amount of carbon dioxide.
Conservation of the Amazon rainforest is one of the greatest environmental challenges of the early 21st century.
The forests are gradually disappearing worldwide at an alarming rate while their role is vital in the global climate of the planet.
Image: Manaus is visible as a white spot, lying at the confluence of two rivers, black and yellow, the Amazon basin. This image was taken September 28, 2008 by camera MERIS (Medium Resolution Imaging Spectrometer) Envisat high resolution (credit ESA).
African Rift lakes
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Lake Victoria (upper center) is the largest lake in Africa and the second largest freshwater lake in the world.
The waters of Lake Victoria is shared by three states. North is Uganda, Tanzania and South North East Kenya.
Lower left is the longest freshwater lake in the world, Tanganyika (670 km long, 1470 m deep and 32 900 km2).
Its waters are shared by four states in northern Burundi, north-eastern Tanzania, the Congo to the west and the southern Zambia.
North of Lake Victoria are Lake Kyoga, Lake Albert (160 km) is located in the upper left, Lake Edward and Lake Albert in Lake Kivu in Lake Edward.
Image: African Great Lakes of the fault in the western Great Rift Valley as seen by Envisat. This picture shows details of 300 m on the ground.
Picture taken October 6, 2008 by camera MERIS (Medium Resolution Imaging Spectrometer) Envisat high resolution (credit ESA).
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Aral Sea is in Central Asia, straddling two countries, Kazakhstan and Uzbekistan.
This great inland sea retreated into several separate reservoirs, it is converted into a salt lake, narrowing steadily during the second half of the 20th century.
The waters of two main rivers feeding the sea, the Amu Darya in the south and the Syr Darya in the northeast, were used to irrigate cotton plantations in the region, which has transformed the Aral Sea a desert called the desert Aralkoum.
Of the Aral Sea in 2009, it remains that two lakes, one in the south and another smaller north.
The withdrawal of the Aral Sea a few years added to successive droughts have left ports in full land destroying the fishing trade.
The bed of the Aral Sea has an area of about 65,000 km2, of which more than half turned into desert. Constant winds and poor vegetation cover cause intense erosion creating small sand dunes of 5 to 6 km in record time. Sand storms, more frequent in the region of the Aral Sea, have serious impacts on flora and fauna. The major challenge for the 50 million people in the region, is to spend means sound management of water throughout the basin.
The large brown spot south of the Aral Sea is the delta of the Amu Darya region of intensive agriculture. Uzbekistan, a country of 27 million people is now the second largest exporter of cotton after the United States.
Cotton is the primary economic resource. Rehabilitation of the Aral Sea began in 2001 with the construction of a concrete structure 13 km long lasting to contain the waters of the Little Aral.
The waters of the northern part of the Aral Sea are mounted 12 m to 42 m. Its surface has increased by 30%. Salinity dropped to an acceptable level for the reintroduction of extinct species of fish.
Fishery was revived and a revival with a climate effect of dew and rain more frequent.
Image: Lower right of the image, the Kyzyl-Kum desert. picture taken March 6, 2009 by camera MERIS (Medium Resolution Imaging Spectrometer) satellite Envisat.
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Typhoon Melor seen from space, image taken by the Envisat satellite on October 6, winds over the Pacific Ocean, northwest of the Philippines and is about to hit Honshu, the main island of the Japanese archipelago. Winds generated by Typhoon Melor reached 198 km/h.
Typhoon and hurricane storms are like, tropical cyclone. A hurricane begins in the Atlantic or eastern Pacific, it is called hurricane. When taking birth in the Western Pacific, it is called typhoon. In general typhoons generate stronger winds than hurricanes. Tropical cyclones are large and powerful thunderstorms that form over warm tropical waters when they transfer their heat to the air.
It is essential to know their strength and their path to issue warnings. Observation satellites of the Earth are here to collect this information. That allow instruments ESA's Envisat satellite.
The information sought are the characteristics of tropical cyclones (cloud structure, direction and intensity of winds and waves, temperature and level of the water surface).
Image: In this image taken by the Envisat satellite on October 6, Typhoon Melor the winds over the Pacific Ocean, northwest of the Philippines and is about to hit Honshu, the main island of Japanese archipelago.
Picture taken October 6, 2009 by camera MERIS (Medium Resolution Imaging Spectrometer) satellite Envisat.