NASA - National Aeronautics and Space Administration

Mission: George VI 02 (priority: high)

This is a new flight, designed to improve previous OIB bathymetry measurements (primarily through gravimetry combined with depth-sounding radar) under the southwestern half of the George VI ice shelf. It does this by interlacing the 2011 OIB grid over that portion of the shelf. In addition, it includes three lines from the 2011 “George VI” mission, also on the southwestern portion, for the purpose of measuring dh/dt.

Weather over our target areas today was generally quite poor, with almost the entire Bellingshausen and Weddell Seas covered in low clouds.  The entire coast of West Antarctica from roughly the English Coast to the west was also socked in, as was the northern and eastern Peninsula, most of the Ronne-Filchner drainage, and the polar plateau.  Of our target areas, this left the English Coast, George VI, and Evans Ice Stream relatively clear.  High resolution satellite imagery is not available for this portion of Antarctica during the morning hours when we must make our flight decisions, only some low-resolution imagery.  Therefore we selected the George VI 02 mission mostly on the basis of three weather models (GFS, ECMWF and WRF) suggesting that it had the best chance of clear skies of the three candidates.  This decision was further informed by the fact that the British base at Fossil Bluff, located a short distance north of our grid but also in George VI sound, also reported clear skies this morning.  When we arrived on site, the skies were indeed quite clear except for an isolated stratus layer, which was trapped in the valley between Alexander Island and the southwestern flank of the Peninsula, and directly over the George VI ice shelf.  The top of this stratus was at approximately 1800' above the surface.  This forced us to remain above that altitude, at approximately 2000'.  We successfully obtained radar and gravity data throughout the mission, but only obtained optical data from ATM and DMS on the two ends of each line where the rising terrain climbed out of the stratus, and for portions of the two southwesternmost grid lines over the ice shelf itself, where the stratus began to break up.

All instruments performed well, with the exception of the optical instruments being unable to see through the stratus over the ice shelf.

Data volumes:
AIRGrav: 5 Gb
ATM: 30 Gb
CAMBOT: 9 Gb
DMS: 45 Gb
FLIR: 17 Gb
Ku-Band Radar: 513 Gb
MCoRDS: 1.7 Tb
Narrow Swath ATM: 38 Gb
Snow Radar: 513 Gb

total data collection time: 5.2 hrs