ESA ENVISAT presents detailed portraits of the Earth’s land surface

ESA ENVISAT presents detailed portraits of the Earth’s land surface

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Europe, 11 May 2007: As part of the ESA initiated GlobCover project it has created a detailed portraits of the Earth’s land surface. The detailed portraits of Earth’s land surface have been created with ESA’s Envisat environmental satellite.

Around 40 terabytes of image data was acquired between December 2004 and June 2006 and processed to generate the global composites. The composites will support the international community in modelling climate change extent and impacts, studying ecosystems and plotting worldwide land-use trends.

The United Nations Environment Programme’s (UNEP) Ron Witt said: “The GlobCover data sets should allow UNEP to do frequent monitoring of environmentally-critical sites and known ‘hot spots’ in areas we have under examination around the globe, and to update our knowledge of such changing environmental conditions, in order to alert the global community to emerging problems before it is too late for decision-makers and civil society to take action in this regard.”

The Food and Agriculture Organization of the United Nations (FAO) will use GlobCover products to support many of its activities. “GlobCover products should constitute an important interpretation asset in support of more dynamic environmental parametres such as rainfall and vegetation condition for FAO’s global and national food security early warning programmes on which ESA and FAO cooperate closely,” FAO’s Dr. John Latham explained. “It will also significantly contribute to the monitoring and assessment of global land cover and as such will support the contribution of FAO to the assessment of land degradation and the monitoring of global forest cover.”

Data acquired from Envisat:

The products are based on Envisat’s Medium Resolution Imaging Spectrometer (MERIS) instrument working in Full Resolution Mode to acquire images in polar orbit at an altitude of 800 km with a spatial resolution of 300 metres.

The global composites are produced by processing MERIS images together in a standardised way. Thirteen out of 15 MERIS spectral bands are processed with an upgraded algorithm including tools for ortho-rectification, cloud screening and full atmospheric correction, which accounts also for aerosol.

The global land cover map, which is approximately ten times sharper than previous global satellite maps, is derived by an automatic and regionally adjusted classification of the MERIS global composites. The 22 land cover classes are defined according to the UN Land Cover Classification System (LCCS).