HYDROWEB experiment: LAKE PRODUCT

The products offered by the Hydroweb project consist of continuous, long-duration time-series of the levels of large lakes with surface areas over 100 km2, reservoirs and the 20 biggest rivers in the world.The operational measurement series are updated no later than 1.5 days after a new altimetry measurement becomes available. They cover about 80 large lakes and 300 measurement points along about 20 major rivers.The research measurement series are updated at regular intervals according to the progress made with processing by the LEGOS laboratory. They cover about 150 large lakes and 1,000 measurement points along about 20 major rivers.Continental waters account for only 0.65% of the total amount of water on Earth, 97% being stored in the oceans and 2.15% in the cryosphere. However, these waters have a significant impact on life on Earth and household needs. They also play a major role in climate variability. Water on Earth is continually recycled through precipitation, evaporation and run-off towards the sea. The increasingly accurate characterisation of the water cycle on land surfaces enables more accurate forecasting of the climate and more careful control of global water resources (human consumption and activities such as agriculture, urbanisation and the production of hydroelectric power, for example).
Altimetry missions used are repetitive, i.e. the satellite overflow the same point at a given time interval (10, 17 or 35 days depending on the satellite). The satellite does not deviate from more than +/-1 km across its track. A given lake can be overflown by several satellites, with potentially several passes. The water level and volume time series is operationally updated less than 1.5 working days after the availability of the input altimetry data, for some lakes. Other lakes are also monitored on a research mode basis.
[https://www.theia-land.fr/fr/projets/hydroweb]