Envisat tracking Africa's rivers and lakes to help manage water resources   Envisat radar altimetry-derived river and lake levels for Africa, including the River Niger in Mali and Nigeria and Lake Volta in Ghana. Click on the high-resolution link to see the full image.     Participants at the 03 - 04 October 2005 TIGER Workshop at ESRIN, which was followed by training sessions for the rest of the week.   ESA's ten-instrument Envisat environmental satellite has been observing the Earth for more than three years. Picture by EADS Astrium. Release date: 14 December 2005