Editor’s note: Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet. Following is the seventeenth of her updates on the effort as part of ScientificAmerican.com’s in-depth report on the "Future of the Poles."
AGAP SOUTH CAMP, ANTARCTICA—Weather pinned us down most of the time between Christmas and New Year’s Day. Since the weather cleared, we have been trying to fly whenever we can. We are working with two teams of pilots, so on good days we can keep the plane in the air almost 22 hours. After breakfast, one team takes off on a five-hour mission, usually to the north over the top of the ice sheet toward the summit of the mountains.
When the morning team plane returns, the crew refuel the aircraft from the fuel bladders, keeping one engine turning to power the science equipment. The team then flies for another four to five hours, returning just in time for dinner. The night team begins its two flight missions right after dinner. This way, we can collect almost 4,000 km of data a day using about 1,100 gallons of fuel.
Of course, sometimes things don’t go quite as planned. We all get a pit in our stomachs when we hear the airplane landing long before it’s due to return, or when the iridium satellite phone rings. Sometimes, aircraft problems are the reason for the premature return. The airframe was used in Alaska last summer, where it got very wet, and we have been plagued by water in the fuel, especially in the tanks in the wing tips. Sometimes, it’s the science gear that hiccups.
The GPS navigation system, so reliable in cars in the mid-latitudes, can be finicky here where the satellites never pass directly overhead. The orbits are designed more for tropical work. Sometimes, the rough landings on the ice sheet rattle equipment loose and Nick Freason, our engineer, has to track down the source of the problem. Blown inverters and crashed motherboards have all come our way. Other times, it is bad weather that plagues us.
Today the aircraft had to come home early, because the head winds were so strong; another night, the whiteout conditions made for a dicey landing. In between these moments of melodrama, we are filling in our study area line by line as the radar profiles reveal the topography beneath the ice.
With each flight, we appreciate more and more the terrain completely hidden beneath the ice. The log sheets of the scientists and engineers who operate the aircraft are sprinkled with adjectives of pointy mountains, sharp peaks, lakes and canyons. The ice beneath the camp is about 3000 m thick but, just to the north of us, the ice thins quickly to 1500 m, and the rugged terrain appears.
The radar data volumes are huge as we collect approximately 12 MB per second. It will take months to construct a map from this massive data volume. However, the gravity measurements are proving to be a really good way to look at the topography quickly. Each flight line of gravity data is merged into the growing database of the mountain range. We can see V-shaped valleys cut into the high peaks and some deep U-shaped valleys as well. The V-shaped ones result from rivers slicing through the area; the U-shaped valleys are probably the result of ice grinding away at the topography. The pace of the work is grueling, but the growing map buoys spirits.
We are getting close to completing the survey. It is a delicate balance between pushing to finish and keeping people focused. We have all been in Antarctica for more than two months, and at high altitude for almost four weeks.
Today the weather forecast has us grounded again. We cannot fly if the predicted visibility is low at the end of the flight. We are so close to finishing, trying to squeeze in the last 10 flights before we must abandon the camp. Each line adds detail to our understanding and it may be years before anyone has the chance to systematically look beneath the ice here.
The temperatures are beginning to drop and the carpenters are starting to get the camp ready for winter. One way or the other we will be done soon.
Credit: Robin Bell
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