Thanks chiefly to Topex/Poseidon, satellite altimetry has proven a valuable source of data for a broad range of applications. Looking beyond the missions in operational service today, future satellites will need to provide better spatial and temporal coverage so that we can study in particular mesoscale variations and other phenomena more closely.
For the medium term, consideration is now being given to altimetry missions capable of 'scanning' the ocean surface to acquire data at scales of a few tens of kilometres, passing over the same spots every few days. Other projects on the drawing board are based on constellations of dedicated, low-cost microsatellites.
Looking further into the future, the goal will be to monitor relatively rapid ocean variations with a period of less than 10 days at scales below 100 kilometres.
Several options are being considered: either missions with swath instruments, or a constellation of at least three satellites. The currently foreseen missions (still in discussion) are: