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Thursday, 28 March, 2002, 11:23 GMT
'Green' satellite calls home
Land, Esa
Senegal: Intensification of land use can increase soil erosion
Europe's flagship Earth-observation satellite has produced its first images of the planet.

BBC News
Enlarge image Enlarge image
The collapsed Larsen B ice shelf drifts out into the Weddell Sea
Among them is a picture of the Larsen B ice shelf in Antarctica which collapsed in spectacular style earlier this month.

The Envisat image shows how the 3,250-square-kilometre chunk of ice has shattered into thousands of small bergs and is now drifting out into the Weddell Sea.

Other pictures supplied by the satellite - the biggest and most expensive that Europe has ever put into orbit - provide stunning views of Africa.

Environment policy

Envisat was launched on an Ariane 5 rocket from Kourou in French Guiana on 28 February/1 March.

Envisat facts
The size of a bus
8.2 tonnes in weight
Circles the Earth every 100 minutes from 800 km up
10 instruments will scan the planet for environmental changes
Built at cost of 2.3bn euros (1.4bn)
It has a suite of 10 instruments that should vastly improve the range and accuracy of scientific measurements of the atmosphere, oceans, land surface and ice.

Mission controllers have spent the last month switching on and calibrating the craft's sensors - a process known as the "switch on and data acquisition phase".

European Space Agency (Esa) officials say everything is working as it should.

Data from Envisat are sent down once per 100-minute orbit to the Kiruna station located in north Sweden. The information goes through several processing stages before being released to scientists or sold to anyone who might want to buy it.

Rapid warming

The Envisat data will build further on that gathered over the past 10 years by Esa's ERS-1 and ERS-2 satellites, which have already given important insights into the impact of human activity on the environment.

Upwelling, Esa
West Africa: Images that show upwellings of nutrients influence fishing policies
Envisat will provide finer detail and its results will help to shape the environment polices of member states in the European Union.

The first images sent down to Earth from Envisat were acquired by its ASAR radar and MERIS instruments.

Perhaps the most dramatic is the picture of the break-up of the Larsen B ice shelf. Envisat was launched just in time to catch the shelf's final destruction. The collapse of the 200-metre-thick Larsen B is the result of the unprecedented warming experienced in the Antarctic Peninsula region in the last 50 years.

Fishing policies

This type of observation can help scientists understand ice dynamics and ice/climate interactions, and also global ocean circulation patterns.

To prove it is up there: A radar image of Envisat taken from the ground
Image taken with the TIRA system of FGAN-FHR

The MERIS (Medium-Resolution Imaging Spectrometer) instrument was used to detect phytoplankton and chlorophyll concentrations over the West African region.

These types of data feed into fisheries policies because the concentrations mark the areas of high nutrition that attract fish.

Another MERIS image shows the Casamance region of Senegal. It details the seaward flow of sediment which comes from inland soil erosion. Changes in land use can have a dramatic impact on soil loss.

The BBC's Ben Fell
The images focus on areas of climate change
A perfect blast-off
Watch the launch of Envisat on the Ariane 5





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19 Mar 02 | Science/Nature
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