Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Pastimes : The New Qualcomm - write what you like thread. -- Ignore unavailable to you. Want to Upgrade?

To: Clarksterh who wrote (1109)	11/21/1999 7:40:00 PM
From: T L Comiskey	Respond to of 12247

Clark...more on Glacier melt...... NASA Researchers Document Shrinking of Greenland's Glaciers David E. Steitz Headquarters, Washington, DC March 4, 1999 (Phone: 202/358-1730) Keith Koehler Wallops Flight Facility, Wallops Island, VA (Phone: 757/824-1579) RELEASE: 99-33 Greenland's southeastern glaciers are rapidly thinning and their lower elevations may be particularly sensitive to potential climate changes, a NASA study suggests. "The results of this study are important in that they could represent the first indication of an increase in the speed of outlet glaciers," said Bill Krabill, principal investigator at NASA Goddard Space Flight Center's Wallops Flight Facility, Wallops Island, VA. An outlet glacier acts as a major ice drainage region for an ice sheet. "The excess volume of ice transported by these glaciers has had a negligible effect on global sea level thus far, but if it accelerates or becomes more widespread, it would begin to have a detectable impact on sea level," Krabill said. In the March 5 issue of SCIENCE, researchers report the glacial thinning is too large to have resulted from increased ice- surface melting or decreased snowfall. The researchers believe the thinning, as much as 30 feet over five years in some locations, is the result of increasing discharge speeds of glaciers flowing into the Atlantic Ocean. Krabill said surface-melt water might be seeping to the bottom of glaciers. Such seepage may be reducing the friction between the ice and the rock below it, enabling the glaciers to slide with less friction across the bedrock and thus allow more ice to slip off into the ocean, according to Krabill. "The results of this study are significant because they provide the first evidence of widespread thinning of low-elevation parts of one of the great polar ice sheets. The results also suggest that the thinning outlet glaciers must be flowing faster than necessary to remove the annual accumulation of snow within their basins," said Krabill. "Why they are behaving like this is a mystery," said Krabill, "but it might indicate that the coastal margins of ice sheets are capable of responding quite rapidly to external changes, such as a potential warming of the climate." Researchers noted that while some internal areas of Greenland that were surveyed showed ice thickening, areas along the coast showed ice thinning. "Taken as a whole, the surveyed region is in negative balance," Krabill said. In 1993 and 1994, NASA researchers surveyed the Greenland ice sheet using an airborne laser altimeter flown on a NASA P-3 aircraft and measured the thickness of the entire ice sheet. Ten flight lines flown in 1993 in Southern Greenland were resurveyed in 1998. The flight lines in Northern Greenland flown in 1994 will be resurveyed in May 1999. Throughout the study, pilots have used the Global Positioning System and other navigational equipment to fly the same flight path some 400 meters above the icy surface. The results showed three areas in the South accumulating at rates up to ten inches per year. These areas located in the internal sections of Greenland are in regions of high snowfall. In the outer regions of the ice sheets, the researchers reported large areas of thinning, with the rate of thinning increasing rapidly towards the ocean. Most-rapid thinning rates (more than three feet per year) were observed in the lower depths of East-coast outlet glaciers, the researchers reported. The researchers noted that the areas of thinning in the East also saw warmer than normal temperatures for 1993 to 1998. "However, we also observe areas of thinning near the West coast, where many locations were cooler than normal," the researchers reported. These surveys have established baseline data sets that will be extended with information from NASA's ICESAT spacecraft. The ICESAT satellite laser altimeter will be launched in 2001 to measure ice-surface elevations in Greenland and Antarctica.

To: Clarksterh who wrote (1109)	11/22/1999 2:16:00 AM
From: Maurice Winn	Read Replies (3) \| Respond to of 12247

Clark, so much for making stuff up as I go - and thanks for correcting me. I already was corrected by a local reader! The delay between sloppy thinking and being wrong is about 2 seconds. Sorry about that folks [re Coriolis forces causing the ocean movement rather than making the ocean move in circles once started due to the driving forces [wind, temperature and salinity density differences]. I should have known better. I should delay the gap between thinking and typing by at least 2 seconds! More corrections: [I might even have escaped detection on this one] I meant sublimation, not ablation as a means of Antarctic ice getting into the ocean [via the air] though glaciers do erode from ablation. Sublimation would be a water removing process in Antarctica [guessing there!]. Also, when I wrote, < I'm pretty sure that insolation changes are the dominant effect and the expansion and shrinkage of forests [light absorbing greenery], ice cover and cloud cover.> I didn't mean a change in the sun's output. I meant a change in the absorption of that incident light due to light and dark surfaces. With snow and cloud cover, reflection is very large. With foliage cover reflection is low and most of the incident light is absorbed. With deserts, reflection is much more than with foliage. With a water surface on the ocean instead of an ice surface, reflection is low. So a snowy, desert covered landscape with cloudy cool skies will reflect heaps of light and cause cooling. Hence ice ages, once they have a grip, gain ground quickly as snow cover extends, covering foliage. Again, this is my theory - I don't have a url or source sorry. Sorry about the sloppy writing, bad thinking and plain wrongness on the Coriolis force causing the ocean currents. One thing most of us seem to agree on, is there are big climatic changes almost sure to happen, whether caused by people burning fossil fuels or natural causes. These changes could will make things cooler or warmer. Living at sea level if it gets warmer will get you wet! I don't believe [yet] that the 800 bn Ton per year of fossil fuels is sufficient to drive the effect. It seems far too trivial though that's a lot of oil if you put it in a container and look at it. We need the figures: Total tonnes of CO2 in the atmosphere now. Total tonnes of CO2 per year added by burning 800bn T of oil equivalents. Let's see if there is a chemist tempted to figure it out. Then we can figure out the effect that will have. George Gilder has some good stuff on greenhouse effects. I started out trying to argue that there IS a human greenhouse gas effect, but I gave up when I couldn't make a case - not enough oil being burned. Yes, I know C02 is increasing and I've seen the Hawaii graphs. It's increased a lot longer than since the 1950s too if I recall rightly. Though I'm not sure where those measurements were taken. Mqurice PS: How do I type so much? Sloppy thinking helps. I'll try to cut down the mistakes and quantity by not 'making it up so carelessly as I go]. Typing fast helps too.