The DMCii 2010 coverage, acquired for the European GMES programme, captures a moment in time – providing an irrefutable marker for urbanisation, desertification and forest cover against which future coverage can be compared.
DMCii has now almost completed its second full 2011 update of Africa at 22metre GSD cross calibrated within 1% of Landsat, providing a unique resource for resource management in the continent. Sub-Saharan Africa is a vast and diverse landscape with climatic extremes ranging from arid desert to the Congo rainforest. Satellite imagery is an invaluable tool for monitoring region-wide changes in land use and the environment.
Since the DMC satellites acquire very large images, up to 650km wide, such vast areas can be mapped quickly, and in detail using the 22metre resolution imagers on the DMC satellites. Because the DMC imagers are accurately calibrated to Landsat, they enable detailed comparison with the past 30 years of imagery for changes in crops, forests, rivers and towns. Most importantly, because huge areas can be imaged by the DMC constellation within a short time-frame, the images acquired are acquired at a similar point in time, which is vital for effective monitoring. Processing is also minimised for the end-user – large contiguous images can be assembled to produce clear and accurate continental-scale maps with minimal image analysis and manipulation.
Tropical forests present specific challenges. Because rainforests are frequently obscured by cloud, single satellites often had to acquire images for a decade to map an area. In contrast DMCii liberates forest management from this constraint by coordinating a constellation of satellites which, through daily imaging, acquire cloud-free images whenever there is a gap in the cloud. For the first time annual and seasonal tropical forest maps are available, providing vital information for REDD+ monitoring of forest carbon resources.
The DMCii 22m coverage of sub-Saharan Africa is being fully updated in 2011