NASA map excites researchers
The Jet Propulsion Laboratory reported today that:
NASA-funded researchers have created the first complete map of the speed and direction of ice flow in Antarctica.
The map, which shows glaciers flowing thousands of miles from the continent’s deep interior to its coast, will be critical for tracking future sea-level increases from climate change. The team created the map using integrated radar observations from a consortium of international satellites.
“This is like seeing a map of all the oceans’ currents for the first time. It’s a game changer for glaciology,” said Eric Rignot of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and the University of California (UC), Irvine.
“We are seeing amazing flows from the heart of the continent that had never been described before.”
© 2011 Alan Buis and Steve Cole, NASA Research Yields Full Map of Antarctic Ice Flow, NASA Jet Propulsion Laboratory (18 August 2011) (paragraph split)
How this map was made
Methods are always interesting:
The final mosaic assembles 900 satellite tracks and more than 3,000 orbits of radar data (Fig. 1). The data are georeferenced with a precision better than one pixel, here 300 m, to an Earth-fixed grid using a digital elevation model (DEM)(8).
Absolute calibration of the surface velocity data relies on control points of zero motion distributed along the coast (stagnant areas near ice domes or emergent mountains) and along major ice divides (areas of zero surface slope in the DEM) in a set of coast-to-coast ASAR tracks (fig. S1).
The mapping precision varies with instrument, location, technique of analysis, repeat cycle, time period and data stacking.
Nominal errors range from 1 m/yr along major ice divides with high data stacking to about 17 m/yr in areas affected by ionospheric perturbations (fig. S2).
In terms of strain rate, or changes in velocity per unit length, data noise is at the 3 x 10−4 /yr level, which is sufficient to reveal effective strain rates along tributary shear margins over the vast majority of the continent (Fig. 2A).
© 2011 E. Rignot, J. Mouginot, and B. Scheuchl, Ice Flow of the Antarctic Ice Sheet, Science, DOI:10.1126/science.1208336 (published online, 18 August 2011) (paragraph split)
Look at the animated version of the map
With time, visual tools like this will make anthropogenically-induced climate warming deny-ers look even more like “skull in-the sand” airheads — at least to people with operating brains
Not that I think self-interest will eventually step aside for greenhouse gas reductions. Even among the teachable.