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ESA unveils latest map of world’s land cover

ESA unveils latest map of world’s land cover

Copyright ESA

ESA’s 2009 global land cover map has been released and is now available to the public online from the ‘GlobCover’ website. GlobCover 2009 proves the sharpest possible global land cover map can be created within a year.

The map was produced using 12 months of data from Envisat’s Medium Resolution Imaging Spectrometer at a resolution of 300 m.

ESA and Belgium’s Université catholique de Louvain created the map using software developed by Medias France and Germany’s Brockmann Consult on data collected from 1 January to 31 December 2009. GlobCover 2009 was generated within a year of acquiring the final satellite data.

The map’s legend uses the UN Food and Agriculture Organisation’s Land Cover Classification System.

Some 8000 people have downloaded the previous version, GlobCover 2005. These maps are useful for studying the effects of climate change, conserving biodiversity and managing natural resources.

Oil spill in the Gulf of Mexico nears the coast

In this latest image acquired by ESA’s Envisat on Thursday at 16:23 UTC, oil from the massive spill in the Gulf of Mexico can be seen as a dark blue swirl advancing toward the Louisiana coast.

On Thursday night, the oil spill – five times larger than first estimated – had spread to just under 5 km from the coast, threatening environmental disaster.

As efforts are being made by all available resources to help avert the feared environmental catastrophe, Envisat images are being provided to U.S. authorities immediately after they are acquired through the International Charter Space and Major Disasters.

On 22 April the U.S. Geological Survey, on behalf of the U.S. Coast Guard, requested the Charter to provide rapid access to radar and optical satellite imagery of the oil slick. In response, a series of space sensors, including Envisat’s Medium Resolution Imaging Spectrometer (MERIS) and Advanced Synthetic Aperture Radar (ASAR), have been tasked to monitor the situation.

Since this date, Envisat MERIS and ASAR data were provided in near real time and have been used by the U.S.’s National Oceanic and Atmospheric Administration (NOAA).

The Charter is an international collaboration between worldwide space agencies to put satellite [...]

Earth from Space – Typhoon Melor

Earth from Space - Typhoon Melor

Copyright ESA

This Envisat image captures Typhoon Melor spinning in the Pacific Ocean northeast of the Philippines on 6 October before slamming into the main Japanese island of Honshu on Thursday.

As the typhoon approached Honshu, it was generating winds of 198 km/h, but weakened after making landfall. The strong winds associated with Melor have toppled trees and power lines, leaving some 10 000 homes without electricity.

By early Thursday, the storm was moving northwest at 30 km/h, carrying a maximum sustained wind speed reaching 111 km/h, according to the Japan Meteorological Agency.

Melor is the first typhoon to make landfall in Japan since Typhoon Fitow hit in 2007. Last year was the first time in eight years that a typhoon did not hit the island.

Typhoons and hurricanes are different names for the same kind of storm – a tropical cyclone. If a storm begins in the Atlantic Ocean or the Eastern Pacific Ocean it is called a hurricane, and if it begins in the Western Pacific it is called a typhoon. Typhoons usually pack stronger winds than hurricanes.

Tropical cyclones are large powerful storms that rotate around a central area of extreme low pressure. They arise in warm [...]

ESA extends Envisat satellite mission


Copyright ESA

SA Member States have unanimously voted to extend the Envisat mission through to 2013. Envisat – the world’s largest and most sophisticated satellite ever built – has been providing scientists and operational users with invaluable data for global monitoring and forecasting since its launch in 2002.

“The decision to extend the Envisat mission operations, taken during the last ESA Earth Observation Programme Board meeting, is a recognition of the success of the mission, in terms of the wide number of scientific and operational users served and the good technical status of the satellite after seven years of operations,” Envisat Mission Manager Henri Laur said.

Envisat, short for environmental satellite, has a unique combination of 10 different instruments which collect data about Earth’s atmosphere, land, sea and ice – providing scientists with the most detailed picture yet of the state of the planet.

Envisat data have never been in more demand than today, and many of these established services rely upon being able to access near-real time (NRT) data. The data are being increasingly used for routine applications, such as monitoring sea ice, oil slicks and illegal fisheries, which require the fastest possible access to the data so [...]

Satellite imagery shows fragile Wilkins Ice Shelf destabilised


Copyright ESA

Satellite images show that icebergs have begun to calve from the northern front of the Wilkins Ice Shelf – indicating that the huge shelf has become unstable. This follows the collapse three weeks ago of the ice bridge that had previously linked the Antarctic mainland to Charcot Island.

The ice bridge, which effectively formed a barrier pinning back the northern ice front of the central Wilkins Ice Shelf, collapsed on 5 April removing about 330 sq km of ice. As a consequence of the collapse, the rifts, which had already featured along the northern ice front, widened and new cracks formed as the ice adjusted in the days that followed.

Dr Angelika Humbert from the Institute of Geophysics, Münster University and Dr Matthias Braun from the Center for Remote Sensing, University of Bonn have been monitoring the ice shelf using a combination of radar images from ESA’s Envisat satellite and the German Aerospace Centre’s TerraSAR-X satellite.

On 24 April, the satellite data showed that the first icebergs had started to break away from the fragile ice shelf. A very rough estimate suggests that, so far, about 700 sq km of ice has been lost from the Wilkins [...]

Collapse of the ice bridge supporting Wilkins Ice Shelf appears imminent


Copyright ESA

The Wilkins Ice Shelf is at risk of partly breaking away from the Antarctic Peninsula as the ice bridge that connects it to Charcot and Latady Islands looks set to collapse. The beginning of what appears to be the demise of the ice bridge began this week when new rifts forming along its centre axis resulted in a large block of ice breaking away.

The Advanced Synthetic Aperture Radar (ASAR) images acquired on 2 April by ESA’s Envisat satellite confirm that the rifts are quickly expanding along the ice bridge. Dr Angelika Humbert from the Institute of Geophysics, Münster University, and Dr Matthias Braun from the Center for Remote Sensing, University of Bonn, witnessed the recent development during their daily monitoring activities of the ice sheet using data from Envisat and the German Aerospace Center’s TerraSAR-X satellite.

By having a time series of radar satellite images throughout this event, Humbert and Braun are able to determine how the rifts develop and how the narrowest part of the bridge responds to these changes. Knowing these details allows them to learn more about the behaviour of ice under stress.

Satellite acquisitions of the ice shelf are available to the [...]

Hot stuff – 15 years of satellite data over Mt. Etna


Copyright ESA

Using radar images acquired by ESA satellites from 1992 to 2006, scientists have for the first time been able to monitor the long-term behaviour of Mt. Etna, Europe’s highest and most active volcano.

This unprecedented time series of Synthetic Aperture Radar (SAR) observations from ESA’s ERS-1, ERS-2 and Envisat satellites provided crucial information for understanding how the volcano’s surface deformed during the rise, storage and eruption of magma. Changes in surface deformation, such as sinking, bulging and rising, are indicators of different stages of volcanic activity, which may result in eruptions. Thus, precise monitoring of a volcano’s surface deformation, or ‘breathing’, could lead to predictions of eruptions.

Using advanced SAR Interferometry (InSAR) techniques, the team was able to determine the deformation of Mt. Etna’s surface over a long period on a scale of centimetres. InSAR involves mathematically combining different radar images acquired from the same point in space at different times to reveal changes that have occurred on the ground between recordings.

Based on the deformation measurements retrieved from their InSAR analysis during the 1992-2006 time interval and on the recorded volcanic data, the team distinguished two volcano-tectonic behaviours.

“Between 1993 and 2000, Etna inflated with a [...]

Arctic sea ice thinning at record rate


Copyright ESA

The thickness of sea ice in large parts of the Arctic declined by as much as 19% last winter compared to the previous five winters, according to data from ESA’s Envisat satellite.

Using Envisat radar altimeter data, scientists from the Centre for Polar Observation and Modelling at University College London (UCL) measured sea ice thickness over the Arctic from 2002 to 2008 and found that it had been fairly constant until the record loss of ice in the summer of 2007.

Unusually warm weather conditions were present over the Arctic in 2007, which some scientists have said explain that summer ice loss. However, this summer reached the second-lowest extent ever recorded with cooler weather conditions present.

Dr Katharine Giles of UCL, who led the study, said: “This summer’s low ice extent doesn’t seem to have been driven by warm weather, so the question is, was last winter’s thinning behind it?”

Arctic sea ice extent in September 2007 and September 2008 The research, reported in Geophysical Research Letters, showed that last winter the average thickness of sea ice over the whole Arctic fell by 26 cm (10%) compared with the average thickness of the previous five winters, but sea [...]

ESA donates mosaic of global images taken by Envisat to United Nations


Copyright ESA

The European Space Agency today donated a composite satellite image of global land cover provided by its Envisat satellite to the United Nations in Geneva, as a testimony to the current state of our planet, to be handed down to future generations.

The image will be exhibited permanently in the new access building by the Pregny gate in the Palais des Nations compound. Mr Sergei Ordzhonikidze, the Director General of the UN Office in Geneva, accepted the mosaic on behalf of the United Nations from Dr Volker Liebig, ESA Director of Earth Observation Programmes, donating it on behalf of the European Space Agency.

The image is a mosaic of global land cover images taken by the MERIS instrument onboard ESA’s environmental satellite which shows the entire planet ‘in its true colours’. To produce the mosaic, a total of 1561 satellite orbit passes were used over the period May-November 2004. “Forests, desert, mountains and oceans are clearly visible. The mosaic shows the state of the planet at the beginning of the 21st century from a perspective only satellites can deliver”, said Volker Liebig.

Launched in 2002, Envisat is the largest Earth observation spacecraft ever built. It carries ten sophisticated [...]