Despite being faced with adverse weather conditions and mechanical problems during their mission over the Antarctic, IceBridge researchers have still managed to make seven total flights over the South Pole, Amundsen and Weddell Seas on their way to completing their mission this weekend.
In order to gain a better understanding of what's going on at Earth's poles, NASA has embarked on the six-year campaign to survey and monitor areas of Earth's polar ice sheets, glaciers and sea ice.
The IceBridge mission, as the campaign is called, is the largest airborne survey of Earth's polar ice ever flown. It will yield never-before-seen 3-D images of Arctic and Antarctic ice. The flights provide a yearly, multi-perspective look at the behavior of the rapidly changing features of the Greenland and Antarctic Ice Sheets and the glaciers that run from them into the oceans.
The first IceBridge flights were conducted in 2009. The first flight, which took place in March through May of that year, surveyed Greenland. The second 2009 flight was conducted in October and November and examined Antarctica. The third mission took place in March through May 2010 and surveyed Greenland and Arctic Sea ice. This most recent mission is the fourth of the campaign, and is concentrated over Antarctica. [ See images from the latest campaign. ]
The missions were begun in part because of the death of the ICEsat satellite, which previously took various measurements of the Antarctic ice. Until the next ICEsat is up and running in 2015, the task will fall to researchers to continue making measurements.
"These are critical measurements, because they will allow us together with data from the previous ICEsat to construct a seven-year time series," said Michael Studinger, a researcher with the mission. "It's important because we need a long base time to determine changes in the ice thickness and elevation, without the current data, we'd have a six-year gap in information." The first flight of this mission occurred Oct. 27. IceBridge's DC-8 plane, packed with scientists and equipment, traveled along a pair of lines from 2009's mission that extend across the sea ice from the tip of the Antarctic Peninsula to south of Cape Norvegia, and back again. During this flight, researchers used Lidar (Light Detection and Ranging), an optical remote-sensing technology that measures properties of scattered light to measure properties of the ice, such as how thick it is.
Typically, the DC-8 plane that is used to fly the missions has 24 people on each flight, including pilot, crew and researchers.
"A typical mission is between 11 and 12 hours, and much of that is spent in transit," said Seelye Martin, a research scientist from the University of Washington. "We spend around three hours flying out and three hours back, which leaves us just five to six hours of time to record data."
More recently, the team flew a mission following the arc of the 86 degrees south latitude line, tracing the same path as the mission in 2009.
The 12-hour mission allowed NASA's Land, Vegetation and Ice Sensor (LVIS) equipment to map the surface of the ice sheets deeper into the Antarctic continent. LVIS takes measurements of surface height using a laser altimeter. Using its readings, scientists can calculate the height of the ice below. The goal of this particular flight was to compare LVIS findings and measurements from NASA's ICESat (Ice Cloud and land Elevation Satellite) satellite. In addition, the LVIS observations will enable researchers to monitor long-term interior ice sheet change for current and future near-polar satellite mission data.
"Basically, with these missions, we are trying to avoid an 'oh my God' moment, we wanted to be able to take continuous measurements in a sensitive, rapidly changing area," Martin said.
The mission has five more flights planned, with their last flight scheduled for this Sun., Nov. 21.
- In Images: NASA's IceBridge in Action Over Antarctica
- NASA's IceBridge Mission Flies Over South Pole
- Image Gallery: Ice of Antarctica