More Water Circulates In Africa & America
More Water Circulates In Africa And America Than Previously Expected
By Marietta Gross - Austria
Scientists of the Geo-Research-Centre in Potdsdam (GFZ) have found that more water exists on the planet than initially thought. New satellite maps based upon data of Grace-Satellites, which measure the gravitational force of the Earth, have delivered information that has scientists wondering.
Satellite groups pass above regions with increased gravity. The satellites map the regions from differing aspects and perspectives. Radar equipment on board the satellites identify the distance of both satellites to the nearest millimetre. GPS-receivers detect their position. This creates an accurate map.
Now a scientist team at the Geo-Research-Centre in Potsdam has been able to calculate the amount of water on the earth. GFZ-physicist Markus Rothacher said large water masses tend to increase the gravitational force. "We were able to filter out other effects," Rothacher said.
He said South America's rainy season rinsed millions of tonnes of water into the Amazon River. The water level was rose by 20 centimetres. Karl Heinz Ilk from the University Bonn said: "The moved amount of water was a third higher than expected." In the following four months the surface of river and ground water in the Amazon Basin descended by 20 centimetres, while Venezuela experienced heavy rain-falls.
More water seems to circulate in some places. The scientists found that the South Asian Monsoon region, and, the African tropical regions have comparable amounts of rain to the Amazon. "That was really surprising," said Ilk.
The river valleys of Siberia experience huge amounts of melting and rain water in spring. The surface there rises by 15 centimetres on average, more than double than expected.
Scientists believe that the world faces a climatic water shortage, and that the Grace-Data might be a warning of excessive usage of ground water.
The scientists report in the "Geophysical Research Letters" based on the Grace-Data that during the heat summer in 2003 Europe's water levels declined by eight centimetres.
The new water balance might also be used for climate research including studies into how humans alter natural water circulation and what impact this had regionally and globally.