Below I took some screen grabs from the Goddard animation. The image shows three frames of the Greenland ice sheet slumping from the summit to the sea. This gives you some idea what models calculate but never display. It is done much better in the actual video.
The other image displays for the very first time the highly contoured subglacial thickness surfaces, starting with the usual contemporary view, followed by stripping off Holocene ice to reveal the 11.7 kyr surface, and finishing with the Eemian ice which is much more extensive than previously thought.
Again, we don't need this fancy perspective view and hopefully we can replace it soon with a higher resolution scientific grayscale, from which anyone can produce their own bump map in a few seconds. The reason for going scientific is the asymmetry: it's all but impossible to recover underlying data from a perspective.
There is some confusion here between portraying the isochronal surface by its elevation relative to sea level (or bottom of NGRIP) vs portraying its thickness, which will differ according to ± departure of bedrock topography from sea level. The former smooth surface is what you'd see in an ice core; the latter bumpy surface is wanted for gravitational driving stress.
The 'age volume' is an interesting concept. This takes any two dated surfaces and computes the volume of ice between them over all Greenland. Fitting this data to per-year volume then measures net retained accumulation over the 100 kyr available. The newtonian volume integrals can be done in Gimp simply by subtracting the two grayscale surface elevations and summing via the histogram and mean value theorem.
A good quote from lead author MacGregor:
“Prior to this study, a good ice-sheet model was one that got its present thickness and surface speed right. Now, they’ll also be able to work on getting its history right, which is important because ice sheets have very long memories.”http://www.nasa.gov/content/goddard/nasa-data-peers-into-greenlands-ice-sheet/#.VMK3dWTF-QM
This is neat quote too:
Flying over northern Greenland during the 2011 Ice Bridge season, Kirsty Tinto, a geophysicist at Lamont-Doherty, sat up straight when the radar images began to reveal a deformed layer-cake structure. “When you’re flying over this flat, white landscape people almost fall asleep it’s so boring—layer cake, layer cake, layer cake,” said Tinto, a study coauthor of Bell 2014. “But then suddenly these things appear on the screen. It’s very exciting. You get a sense of these invisible processes happening underneath.”
MacGregor's online CV suggests two follow-up papers are coming soon. These had to await prior publication of the isochron database paper under discussion here. If they have actually been able to wring some experimental temperature data out of the radar archive, that would be huge news. MacGregor has 5 previous publications on englacial radar attenuation, mostly in Antarctica.
MacGregor, J.A., J. Li, J.D. Paden, G.A. Catania, G.D. Clow, M.A. Fahnestock, S. Gogineni,
R.E. Grimm, M. Morlighem, S. Nandi, H. Seroussi and D.E. Stillman,
Radar attenuation and temperature within the Greenland Ice Sheet,
Journal of Geophysical Research Earth Surface (same journal, in press)
MacGregor, J.A., W.T. Colgan, M. Morlighem, M.A. Fahnestock, G.A. Catania, J.D. Paden and S. Gogineni
Holocene deceleration of the Greenland Ice Sheet
Journal not specified (in review)