Antarctic subglacial plumbing mapped from space
description
Transcript of Antarctic subglacial plumbing mapped from space
![Page 1: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/1.jpg)
Helen Amanda FrickerScripps Institution of Oceanography
Ted ScambosNational Snow and Ice Data Center
Bob BindschadlerNASA/GSFC Space Flight Center
Laurie PadmanEarth & Space Research
Photos of Whillans Ice Stream courtesy of Lee Powell and Charlie Bentley, 1987-88 season & edited by Robert Phillips
AAAS/NASA press briefing – San Francisco – 15 February 2007
Antarctic subglacial plumbing Antarctic subglacial plumbing mapped from spacemapped from space
![Page 2: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/2.jpg)
Helen Amanda FrickerScripps Institution of Oceanography,
La Jolla, CA
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 3: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/3.jpg)
NASA’s ICESat mission and launch
Ice Cloud and land Elevation Satellite (ICESat) launched 12 Jan 2003 from Vandenberg, CA Primary goal of ICESat mission is ice sheet change detection
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 4: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/4.jpg)
Schematic of single profile science data measurements, compiled through time to build elevation data sets
ICESat laser altimeter
Surface elevations along a ground track determined from laser time of flight, combined with precise orbit and pointing information ICESat has 3 lasers and is switched on for ~33 days every ~4 months in a repeat track pattern (which enabled this discovery)
Geoscience Laser Altimeter System (GLAS)
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 5: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/5.jpg)
ICESat repeat-track analysis
+ indicates surface uplift (filling)
- indicates surface deflation (draining)
~ indicates oscillating (i.e. doing both)
Conway Ridge
Engelhardt Ridge
Whillans Ice Stream (B)
Mercer Ice Stream (A)
Elevation range 2003-06 (m)
0 9m
MOA (NSIDC)AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 6: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/6.jpg)
Subglacial Lake Engelhardt
Conway Ridge
Engelhardt Ridge
Largest event in magnitude: deflating
WAIS Meeting 2006
ICESat elevation range (m)
0 9
Whillans Ice Stream (B)
Mercer Ice Stream (A)
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 7: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/7.jpg)
Ted ScambosNational Snow and Ice Data Center,
Boulder, CO (by telephone)
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 8: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/8.jpg)
Conway Ridge
Engelhardt Ridge
Elevation range 2003-06 (m)
0 9m
+ indicates surface uplift (filling)
- indicates surface deflation (draining)
~ indicates oscillating (i.e. doing both)
Satellite image differencing
Uplift
Subsidence
Whillans Ice Stream (B)
Mercer Ice Stream (A)
MOA (NSIDC)AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 9: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/9.jpg)
Hydraulic potential map
Conway Ridge
Engelhardt Ridge
Conway Ridge
Engelhardt Ridge
Whillans Ice Stream (B)
Mercer Ice Stream (A)
Whillans Ice Stream (B)
Mercer Ice Stream (A)
Elevation range 2003-06 (m)
0 9m
MOA (NSIDC)AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 10: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/10.jpg)
Hydraulic potential map
Engelhardt Ridge
Conway Ridge
SGL Engelhardt
SGL Conway
SGL Whillans
SGL Mercer
IMPORTANT: This is *not* topography
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 11: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/11.jpg)
MODIS difference image: December 2005 minus December 2002
Subglacial Lake Engelhardt
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 12: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/12.jpg)
Bob BindschadlerNASA Goddard Space Flight Center,
Greenbelt, MD
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 13: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/13.jpg)
Drawdown vs time at 3 crossovers
Subglacial Lake Engelhardt
Total volume loss ~ 2.0 km3
to ocean cavity under Ross Ice Shelf through subglacial channel
AAAS/NASA press briefing – San Francisco – 15 February 2007
![Page 14: Antarctic subglacial plumbing mapped from space](https://reader030.fdocuments.us/reader030/viewer/2022020718/5681680f550346895ddd9a0e/html5/thumbnails/14.jpg)
Conway Ridge
Engelhardt Ridge
Whillans Ice Stream (B)
Mercer Ice Stream (A)
How much water in the system?
Isolated Subglacial Lake Engelhardt lost ~2.0 km3 over the observation period (33 months)
Elevation range 2003-06 (m)
0 9m
-2.0 km3
SgLE
SgLC
SgLM+1.2 km3
+0.12 km3
+0.27 km3SgLW
Remainder of the system had a net gain ~1.6 km3 over the same period (~0.6 km3a-1)
Net water gain is likely both reflecting and influencing the motion of these major Antarctic ice sheet outlet streams
AAAS/NASA press briefing – San Francisco – 15 February 2007