|
|
News  Envisat making sharpest ever global Earth map
The most detailed portrait ever of the Earth's land surface is being created with ESA's Envisat environmental satellite. The GLOBCOVER project aims at producing a global land cover map to a resolution three times sharper than any previous satellite map. It will be a unique depiction of the face of our planet in 2005, broken down into more than 20 separate land cover classes. The completed GLOBCOVER map will have numerous uses, including plotting worldwide land use trends, studying natural and managed ecosystems and modelling climate change extent and impacts.
Envisat's Medium Resolution Imaging Spectrometer (MERIS) instrument is being systematically used in Full Resolution Mode for the project, acquiring images with a spatial resolution of 300 metres, with an average 150 minutes of acquisitions occurring daily.
Other Envisat sensors will work in synergy with MERIS. The Advanced Synthetic Aperture Radar (ASAR) instrument will be used to differentiate between similar land cover classes, such as wetlands and humid tropical rainforests. And information from the satellite's Advanced Along Track Scanning Radiometer will be used to correct for atmospheric distortion and to perform 'cloud masking', or the elimination of cloud pixels.
An international network of partners is working with ESA on the two-year GLOBCOVER project, which is taking place as part of the Earth Observation Data User Element (DUE).
Participants include the United Nations Environment Programme (UNEP), the Food and Agriculture Organisation (FAO), the European Commission's Joint Research Centre (JRC), the International Geosphere-Biosphere Programme (IGBP) and the Global Observations of Forest Cover and Global Observations of Land Dynamics (GOFC-GOLD) Implementation Team Project Office.
Located at Friedrich-Schiller University in Jena, Germany, the GOFC-GOLD Implementation Team Project Office is responsible for developing international standards and methodology for global observations, and is advising GLOBCOVER on classification issues.
The GLOBCOVER classification system is being designed to be compatible with the Global Land Cover map previously produced for the JRC for the year 2000, a one-kilometre resolution map produced from SPOT-4 Vegetation Instrument data and known as GLC 2000.
Once worldwide MERIS Full Resolution coverage is achieved, there will actually be two GLOBCOVER maps produced. The first, GLOBCOVER V1, will be produced automatically by mosaicking images together in a standardised way.
Acquired in a standardised 15 bands, the MERIS images are going to be processed with an upgraded algorithm that includes an ortho-rectification tool, correcting for altitude based on a digital elevation model (DEM) derived from the Radar Altimeter-2 (RA-2), another Envisat instrument.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
