ENVISAT | | | | |
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| The satellite ENVISAT | | others...   | | Category: probes and satellites |
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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.
| Envisat | | Satellite observation |
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| Launch | | 01/03/2002 | | Masse | | 8 211 kg | | Launcher | | Ariane 5 | | Peri apside | | 785 km | | Apo apside | | 791 km | | Period | | 100,6 minutes | | Orbit | | circular, helio synchrone | | Inclination | | 98,6° |
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* 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. |
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| The 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. * Photograph taken by the spectrometer (MERIS) instrument Envisat October 3, 2005 (image covers an area of 672 672 km).
Credits: ESA | | 
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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.
* Photography of islands around the region Samoylov taken July 5, 2005 by the Compact High Resolution Imaging Spectrometer (CHRIS).
Credits: ESA | | 
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The 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 of Atlantic misrepresentation of color, cold blue waters and red the warmest.
Credits: ESA
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