African lakes as seen by Topex/Poseidon and now Jason-1 (in red, satellite ground tracks). Lakes' variations depend mainly on climate (e.g. precipitations linked to Indian Ocean Temperature for the Great Lake region), or for reservoirs, (Lakes Nasser, Volta, Kariba) of their regulation.  Click on a lake to see the variations of its level since 1992 (Credits Legos/CLS)

Altimetric satellites are optimized for ocean or ice observation. However, every stretch of water or even flat surface can give valid data - as long as the satellite fly over them. Twelve African lakes can thus be monitored since 1992 from Topex/Poseidon measurements. Topex/Poseidon shift on an intermediate orbit (since August 15, 2002) should increase the number of lakes that can be observed.

See also:

• Applications: Hydrology
• Dossiers: Altimeters chart water levels

Websites on this subject:

• The African Great Lakes
• The International Decade for the East African Lakes (IDEAL)