Scientists and engineers at the Center for Remote Sensing of Ice Sheets (CReSIS), located at the University of Kansas, US, are developing technology that responds to climate change. Their computer models measure and predict not only the response of ice sheets to changes in climate, but also the effect these changes may have on current sea levels.
CReSIS is a partner in IceBridge, a six-year NASA mission and the largest airborne survey of Earth's polar ice. Today, large ice sheets (masses of glacier ice) exist in both Greenland and Antarctica, with the single largest mass - an ice sheet holding nearly 90% of Earth's fresh water - in Antarctica. The Greenland ice sheet, the second largest, occupies around 80% of the surface of Greenland.
The thickness of these ice sheets is so incredible - think in terms of miles - that imagining a significant melt is difficult. However, research scientists, universities, and agencies are all working hard to understand how ice will respond to climate change.
John Paden, Assoicate Scientist at CReSIS, explains, "Polar ice sheets are very important to understanding climate change for a number of reasons. Ice cores provide paleoclimatic records with amazing resolution to more than 100,000 plus years ago. Ice sheets have a certain sensitivity to climate change, and finally, their effect on sea level rise - which in the last interglacial was 20 or so feet higher than today - a real difference, and almost all of it came from ice sheet melt."
Paden runs the signal and data processing group at CReSIS. "Currently four different radar systems are involved in data collection on the IceBridge DC-8: Multichannel Coherect Radar Depth Sounder (MCoRDS) that measures all the way to the bottom of the ice sheet, the Accumulation Radar which measures a couple of hundred meters into the ice, the Snow Radar which measures 20-40 m into the ice, and the Ku-band Altimeter that measures just the top surface. Generally with our radars, the less penetration the radar has, the better its resolution - around 5 m in ice for the deepest penetration, down to 5 cm for the Snow Radar and Ku-band Altimeter."
When your radar and research laboratory fly in some of the harshest weather conditions known to man, nothing is routine. The aircraft, equipment, and systems are all installed, checked, and rechecked - not only on the ground, but also in the air well before the mission ever begins. Along with being unpredictable in nature, this research mission debuted new technology that made it particularly remarkable. A new system developed at Indiana University, US, now helps researchers process and archive data before landing.
Matt Standish, team lead for the Campus Bridging and Research Infrastructure group, part of Indiana University's Pervasive Technology Institute (PTI), led the development and integration of the system on its maiden flight. Faced with scientists' needs to process real time data and create MD5 hashes and archive copies, Standish started problem solving. "Essentially, the new in-flight data copy system takes a clustered computing system and high-speed network into the air."
Carson Gee, Manager of Information Technology at CReSIS, collaborated with Standish in testing the new system and played an important support role aboard the DC-8 aircraft. "There are a lot of problems that happen in an aircraft over Antarctica that you would never expect: cold hard drives spinning at reduced speed, servers overheating because of additional safety reinforcements, power issues, vibration, and unexplained memory errors. We really saw a lot of strange behavior, and all without the luxury of having the Internet to look up information or troubleshoot."
With instant access to their data, CReSIS scientists can now determine in-flight which polar ice sheets require a closer look - eliminating the need to land and then schedule a new flight. "Previously, backups were done by hand-copying drive to drive, and the processing resources were a couple of small computers. The new setup has a 96 core computer cluster with multiple SSD RAIDs and real time backups." explains Paden.
"We can now process the data faster which means we can apply more powerful algorithms or see results faster, and we now require less personnel for backups and processing resulting in cost savings."
Rich Knepper, manager of Campus Bridging and Research Infrastructure, points out, "The new system allows for immediate archive and verification of data. Once radar data collection has stopped, processing starts and scientists get results before the plane lands. Gee also notes, "Radar calibration and software errors can be identified quickly, saving valuable time and providing mission science with more timely information to guide flight selections."
The IceBridge mission collected nearly 104 terabytes of data (10 times the printed collection of the US Library of Congress). Following basic in-flight processing, CReSIS completes higher-level data processing on Indiana University's Quarry system, and uses the university's Data Capacitor (soon to be replaced by Data Capacitor II) and Scholarly Data Archive for short and long term storage. Once the CReSIS team completes processing the data products are housed at the National Snow and Ice Data Center.
Known for proven and creative approaches to data management and storage solutions, the team is looking to make future enhancements to the tool. "We need to be able to handle a higher data rate, and we would like the tool to be easy enough for radar operators to use. Ideally we would like to be able to control and troubleshoot remotely." says Standish.
Knepper confirms the challenges ahead, "Managing a cluster over the satellite internet link on IceBridge aircraft is extremely complex - it's more in line with NASA's other work - from incredible distance managing a computer with attended latency and with minimal ability to affect physical elements of the system."
Visit NASA's website to view a video of the IceBridge mission, including the purpose of the day's flight, the challenges of working with Antarctic weather forecasts, and what the team found when they arrived on site.