Nasa satellites help create digital waterworld

Around 30 per cent of Earth's fresh water, a total of 23,400,000 km3, ebbs and flows below the planet's surface in rivers and reservoirs. These images, by Jay Weeks, a Los Angeles-based designer, shows how these groundwater levels fluctuate underneath our planet over time. To create the interactive visualisation, Weeks used 64,800 publicly available data points from Nasa's twin-satellite Gravity Recovery and Climate Experiment. These satellites, launched in March 2002, map variations in the Earth's gravitational field, caused in part by the movement of the planet's water.

The visualisation, which maps the distribution of ground-water against the long-term average for each area, shows seasonal variations. During wet seasons and winters, more water flows into aquifers, then the level diminishes as water resurfaces through streams and springs, unless replenished by more rain. The wettest month of the year is April, when the global average rises by 21.8mm thanks to the rainy season in the Amazon and elsewhere in the southern hemisphere. In October, Earth's driest month, drought across sub-Saharan Africa and South America pushes the global average 18.1mm below average.

"This project serves as proof of the potential of public data," says Weeks, 24. OK, but why does the UK still have a hosepipe ban?

Source: http://www.wired.co.uk