April 29, 2002. Copyright 2002. Graphic News. All rights reserved.

Space-based network to monitor climate change

LONDON, April 29, Graphic News: NASAÕs mission to understand and protect our home planet will mark a major milestone on Saturday with the launch of the Aqua satellite from Vandenberg Air Force Base in California atop a Boeing Delta launch vehicle.

The $952 million craft -- a joint project between the United States, Japan and Brazil --  is the latest sibling in a family of Earth Observing System (EOS) satellites dedicated to studying the Earth and our knowledge of global climate change.

Aqua will follow Jason 1 and a pair of twin spacecraft called Grace, launched in December and March respectively, and NASAÕs Terra spacecraft, launched in December of 1999. Although each is different, the missions are designed to help piece together the puzzle of how water moves between the EarthÕs atmosphere, oceans and land.

Jason 1, a joint U.S.-French mission, uses radar to measure the topography -- or shape -- of an oceanÕs surface. Grace, a joint U.S.-German mission, measures tiny variations in the EarthÕs gravity field, including those caused by the shifts in mass caused by large-scale movements of water. AquaÕs sister satellite, Terra, is collecting what will ultimately become a new global data set on which to base scientific investigations about environmental change. Fifteen more EOS spacecraft are due be launced over the next four years.

ÒAqua will provide unprecedented information on the global water cycle. The spacecraft will enable agencies to create more accurate weather forecasts in the future,Ó said Ghassem Asrar, Associate Administrator for NASAÕs Earth Science Enterprise.

In addition to improved forecasts scientists hope Aqua will provide better advance notice of El Ninos and a clearer understanding of how human activity affects the world at large. Equipped with six state-of-the-art instruments, Aqua will collect data on global precipitation, evaporation, and the cycling of water.

Global change is inevitable, and has been ongoing throughout the EarthÕs 4.5-billion-year history, explained Asrar. The Sahara Desert was once lush and fertile, North America a bleak glacial landscape, and the Great American Desert a seabed.

Today, there is compelling scientific evidence that human activities have attained the magnitude of a geological force and are speeding up the rates of global changes. For example, carbon dioxide levels have risen 25 percent since the industrial revolution and about 40 percent of the worldÕs land surface has been transformed by humans.

Water -- and with it, energy -- moves through the world at varying paces before returning to the oceans that cover 70 percent of the planet. That cycle drives both climate and weather, affecting in turn life and its every activity. Water lasts just days in clouds as a vapour but weeks as a liquid in the worldÕs rivers, and as ice it can remain locked in the polar caps for tens of thousands of years.

Monitoring waterÕs movement -- where, how quickly and in what phase it moves -- requires a global perspective, something scientists hope the flotilla of Earth-orbiting satellites can provide.

Teams of scientists and researchers from North and South America, Asia, Australia and Europe will put the data to work to keep tabs on droughts, hurricanes before they make landfall, and other markers that, together, suggest climate change. In a first for NASA Aqua data is also to be plugged into daily weather forecasts.

/ENDS



Source: NASA Goddard Space Flight Center