A remote-sensing instrument launched by the European Space Agency on its Envisat. The primary mission of MERIS is to observe the Earth's oceans and coastal zones, but it will also investigate the atmosphere and land areas. This will increase the understanding of the climate system and global climate changes. The spectrometer uses five cameras that cover a 1 150-km band of the Earth's surface. Measurements of the Sun's reflected radiation from the Earth are taken in the visible and near-infrared part of the spectrum. The ocean data will measure algae, plankton blooms, suspended matter (including sediments), dissolved organic material, and coastal erosion. The atmospheric studies will provide information on clouds, water vapour, and aerosols, and the land observations will focus on vegetation.