For those FWers who are interested in the global warming controversy, the following article from today's Washington Post will be of interest. The article starts off mentioning two scientific satellites which are being launched at the same time, but I've only retained info about the climatic satellite in the following excerpt:
<<<< NASA SATELLITES' MISSION TO RUN HOT AND COLD William Harwood NASA is launching two modest but scientifically ambitious satellites this week to answer fundamental questions about the forces shaping Earth's environment, from the surface of the planet to the depths of interstellar space. The Ice, Cloud and Land Elevation Satellite -- ICESat -- is designed to find out whether the polar ice sheets are expanding or melting, either scenario a tell-tale sign of environmental change on a vast scale. The other satellite, the Cosmic Hot Interstellar Plasma Spectrometer, or CHIPS, will study how the debris from exploding suns cools and ultimately becomes the raw material for new stars in a galactic recycling program. Both satellites are scheduled for launch Thursday atop a Boeing Delta 2 rocket from Vandenberg Air Force Base, Calif. Of the two, ICESat is the star of the show, costing $282 million, including data analysis and the price of the Delta 2 rocket. Once operational in a 373-mile-high orbit around Earth's poles, ICESat will use a sophisticated device known as a laser altimeter to collect precise elevation data that will help researchers determine the ice-sheet mass balance, that is, how much new ice forms every year compared with how much is lost. "The ice sheets that cover Greenland and Antarctica today are over two miles thick in places," said Jay Zwally, ICESat project scientist. "But very simply, we do not know if they're growing or shrinking. "Almost every newspaper article we read says that when the climate warms, we're going to see the melting of the polar ice sheets and the flooding of coastal areas. The truth is, we really don't know." ICESat is equipped with an instrument known as the Geoscience Laser Altimeter System, or GLAS. By precisely timing how long it takes a laser beam to fire, hit the surface and bounce back to a 31-inch telescope, scientists can determine the elevation of the ice sheets below to an accuracy of six inches. Firing 40 times a second, GLAS will collect readings at approximately one-mile intervals. Zwally said about three-tenths of an inch of water from the surface of the ocean ends up in the planet's ice sheets as snowfall. "That's about three inches every 10 years," he said. "If there was only water going in and nothing coming out, sea level would drop three inches every 10 years. But approximately the same amount is coming back out in the form of icebergs and melting at the edges," he said at a recent news conference. "We don't know which is greater. The difference is what we call the mass balance." Many researchers expect the ice sheets to melt more around the edges and to grow more in the center. Recent measurements in Greenland using aircraft-borne instruments show the edges are melting more than expected. But there is little or no data about what might be going on in the central regions of the ice sheets. "That's what ICESat will do," Zwally said. "ICESat will provide precise measurements over the whole ice sheets from season to season and from year to year." It is a complex problem that until now has been fraught with uncertainty. A United Nations panel on climate change has predicted that over the next 100 years, the sea level could rise from three to 33 inches. Over time, ICESat measurements should allow scientists to chart changes in ice-sheet elevation that are equivalent to a few tenths of a millimeter of sea level change. "For the future, we expect increases in melting and increases in snowfall," Zwally said. "It's going to be a race between the two of these. We're going to get more melting at the edges, more snowfall at the center, and just what the contribution will be is uncertain. It could be either plus or minus." >>>> © The Washington Post Monday, December 16 ---------------------------------------------------------------------------- ------------ Keith Hudson, General Editor, Handlo Music, http://www.handlo.com 6 Upper Camden Place, Bath BA1 5HX, England Tel: +44 1225 312622; Fax: +44 1225 447727; mailto:[EMAIL PROTECTED] ________________________________________________________________________
