Operation IceBridge takes to the air again over Antarctic Peninsula and South Pole
Posted by Jim Cochran
Tales of Poles and Penguins! Operation IceBridge takes to the air again! We had been ‘holed up’ waiting for a break and finally the weather lifted enough to get in a series of flights over the Antarctic Peninsula and a crucially important flight over the South Pole. At 12 hours round trip the flight to South Pole was one of the longest. Flown at 35,000 feet of altitude we tracked along the -86 ? latitude arc around the pole. Our goal was to use the Laser Vegetation Imaging Sensor (LVIS) to measure surface height through a laser pulse that it sends down and is measured as it reflects back from the ice surface.
Why was this flight so important? The data collected will be used to link directly to data collected from the now ‘retired’ Ice Cloud and land Elevation Satellite (ICESat) as well as that collected in flights for IceBridge 2009. This overlap of data is key for calibration of the collected ice surface data. The IceBridge Mission is the interim method of measuring ice sheet surface elevation now that ICESat is not available. The mission plan had been to collect at least a year’s worth of overlapping data, but the satellite did not last to complete this target. Comparing the 2009 and 2010 South Pole flights with the data from earlier NASA’s ICESat orbits is important for internal data calibration (consistency). But why is the South Pole flight so important? ICESat rotated in an orbit near the South Pole so the data it collected converged along the -86? latitude arc. Overlapping with these data points provides the calibration the mission needs to provide long term continuous monitoring. The science team planned that between the 2009 and 2010 years of IceBridge South Pole flights would collect more than a million overlapping observations to compare! The South Pole mission flight was declared a success.
However, every day brings something new and the plane has struggled this season with small repairs. When the plane needs repairs the gravimeter is shut down for a few days, so the gravity team is free to head out of town and see some Patagonian sights – the penguins! There are two penguin colonies accessible from Punta Arenas. One is at Otway Gulf, about 70 km from Punta Arenas down a gravel road, with about 10,000 penguins. This is where most IceBridge folks go to view penguins. The second is on Isla Magdalena, an island in the Straits of Magellan visible on the horizon during our daily drive up the coast to the airport. Since there are over 100,000 penguins on Isla Magdalena, we decided to take the ‘road less traveled’ and booked a boat trip to the island. The penguins spend the day at sea fishing, so viewing needs to be done in the early morning or in the evening.
Thus, at about 2:30 in the afternoon, Kevin and I found ourselves in Rio Seco, a little fishing port outside Punta Arenas. Joining about 10 other tourists we boarded the Nueva Galicia, a 60-foot wooden boat for a pleasant two-hour trip to the island. Toward the end of the trip, we began to see penguins swimming alongside the boat as they returned from their daily foraging trip. Finally, we pulled up at the dock and scrambled ashore where we were met by the resident Chilean park ranger. The island is nicely set up for visiting boatloads of tourists. A roped-off path meanders up from the dock to a lighthouse on the highest point, allowing visitors to get out among the penguins but leaving them undisturbed. These penguins are Magellanic penguins and are little guys. They are listed as about 70 cm, but I think that is generous. As we watched, penguins were continually coming ashore. They sat on the sand near the shore and rested from their day at sea. Every so often, a group of 8-10 penguins would stand up and head off inland toward their burrows. The island was covered with penguin burrows and, since eggs had just been laid, every burrow was occupied by a penguin incubating the eggs.
After about an hour, we wandered back to the dock and were in for quite a surprise! The tide had gone out, apparently catching the boat crew napping. We were high and dry. If the crew had been more alert and backed off from the pier, we could have gone out to the boat in the ranger’s rubber boat, but as it was, we had to wait for the next tide. The captain encouraged us not to worry, assuring us it would not be long and a sailor brought drinks and sandwiches ashore for a very pleasant picnic. However, an hour or so later after dinner, the tide was not coming in. In fact, there seemed to be more rocks exposed. So there we sat, humming the theme song from “Gilligan’s Island”. Finally, around 11 PM the tide began to noticeably rise. We climbed back on the ship and by midnight were floating free. We arrived back at the hotel at the hotel around 3 AM after more of an adventure than we had bargained for. Perhaps the 10,000 penguins at Otway Gulf would have been enough, after all they do all look surprisingly alike!
Jim Cochran is a geophysicts at Columbia University’s Lamont-Doherty Earth Observatory in the Marine Geology and Geophysics division. Jim has worked extensively on processes under the Earth oceans including several projects in the Arctic Ocean including the Gakkel Ridge, a mid-ocean ridge spreading center in the central Arctic, and the adjacent Amerasian Basin. Jim brings extensive gravity expertise to this project.