Between October 23, 2003, and June 2, 2006, average elevation of the ice surface along this Geoscience Laser Altimeter System (GLAS) track dropped from roughly 53 meters to about 44 meters. After March 3, 2006, the elevation drop was negligible, indicating that the event that caused the sinking had ended. (NASA image by Robert Simmon, based on GLAS data courtesy Helen Amanda Fricker, Scripps Institution of Oceanography.)
This elevation change in a subglacial lake was due to the fact it was no longer supported in it's dynamics by an ice shelf off the Antarctica continent.
...Given those expectations, what actually appeared to be going on beneath the Whillans Ice Stream was rather odd. “While one isolated lake lost about two cubic kilometers of water, all the other lakes gained about an equivalent amount of water,” says NASA scientist Robert Bindchadler. “But it’s not the same water because the lake that lost water is downstream of the other lakes and in a separate basin.” The amount of water that accumulated in the other lakes is nearly equal to all the water that pressure and geothermal heat could likely have produced under the Whillans Ice Stream during that period. “Yet—and here’s the really odd part—,” he emphasizes, “this ice stream is slowing down at a consistent rate of about 1 or 2 percent per year. Now if water is the lubricant that lets ice go fast, why, if there is more water, is the ice stream going slower? We have ideas how to answer this, but the seeming contradiction shows us that we don’t understand this system yet.”
So what exactly is happening here. I was hoping Scientist Helen Amanda Fricker would make that call. She is a geophysicist with Scripps. They can't make that call? I will.
The 'distal' Lake Engelhardt is draining into the Ross Sea by hydrostatic pressure. The crevasses are widening because there is sublimination of the top ice. As they widen there is more exposure to the heat delivered to the continent by vortexes and there is more solar radiation reaching more ice surface. As the icemelt runs down the crevasses there is accumulation at the base of thy ice. Therefore there is more instability at the base. Move movement. Probably at this point more traverse of the ice that can be measured similar to that of the Greenland Ice's 'meander.'
As the increased water content is realized at the base, the hydrostatic pressure increases, as the hydrostatic pressure increases the rise and fall of the ice on the continent and the ice sheet will be noted. With the rise and fall of the ice there is 'meander' and that will allow more water to run into the upstream lakes. As these lakes fill the 'tilt' of the ice mass that covers the land mass changes causing a closing of the distal lake. The reason the ice is not moving as fast as before is because there is more fiction with the land surface. Friction over time will build heat and therefore will accumulate it's own under ice water again. The distal lake will fill and when it does the hydrostatic pressure from the upstream lakes will cause a movement again of water now accumulating at the base of the crevasses.
HUMAN INDUCED GLOBAL WARMING is melting Antarctica !
continued below...I am looking for a specific satellite shot, I'll be back.
