Seeing the Silver Lining: Challenges and Champions of Arctic Cloud Studies on Alaska’s North Slope

 
Published: 12 January 2015

Unmanned Aircraft at Oliktok Point

The AMF3 is the newest of the ARM mobile facilities and will be stationed on the North Slope for an extended period.
The AMF3 is the newest of the ARM mobile facilities and will be stationed on the North Slope for an extended period.

Welcome to the North Slope of Alaska, home to polar bears, caribou, arctic foxes, petroleum-rich wilderness, and four nautical miles of restricted air space. At Oliktok Point, along the Beaufort Sea, the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility deployed its third ARM Mobile Facility (AMF3) giving scientists another platform to study arctic clouds, aerosols, and other atmospheric phenomena—including from the sky with unmanned aerial systems (UAS). Over a two week span in October, two different teams worked with unmanned aircraft in that airspace to take atmospheric measurements.

The teams were welcomed to the U.S. Air Force radar station at Oliktok Point by a staff of friendly personnel who prepared everything needed for a successful field campaign. Aside from gym equipment and tasty meals, the accommodations also provided consistent access to Wi-Fi, which was a favorite asset of the team. Shortly after their arrival, the teams were required to watch a training video on interactions with polar bears. The gist of the message was this: not all encounters with the large creatures end badly, but avoiding them is best for everyone involved.

Two Teams, Similar Goals

There were two teams on site; the first team was made up of scientists from the University of Colorado (CU) and the second team was a combination of staff and scientists from New Mexico State University (NMSU) and Sandia National Laboratories (SNL). The CU team operated the DataHawk, a small lightweight plane that measures temperature, humidity, pressure, and estimates wind speed. The NMSU/SNL team operated the tethered balloon system, which was operated from a trailer and is capable of carrying a wide variety of instrumentation. In addition to aerial measurements, both teams utilized the AMF3 for ground-based observations—and shelter from the harsh arctic environment.

The CU team prepares for launch using a bungee cord to propel the DataHawk to a high enough speed that it becomes airborne, after which, it is controlled via a remote. The tethered balloon system is visible in the background with its operations trailer. (Click to enlarge for a closer look.)
The CU team prepares for launch using a bungee cord to propel the DataHawk to a high enough speed that it becomes airborne, after which, it is controlled via a remote. The tethered balloon system is visible in the background with its operations trailer. (Click to enlarge for a closer look.)

The scientists from CU Boulder are part of the Cooperative Institute for Research in Environmental Sciences (CIRES) team and were conducting engineering evaluations of the DataHawk under the Coordinated Observations of the Arctic Lower Atmosphere (COALA) study. Their main objective, according to lead scientist Gijs de Boer, was to “make measurements necessary for estimating turbulent surface fluxes of heat and moisture between the surface of the Earth and the lower atmosphere.”

The combined NMSU/SNL team, led by Darin Desilets, tested a weather balloon tethered to a trailer or truck by a cable/winch system. When the weather cooperated, this system allowed the balloon to obtain vertical profiles—measurements from in, around, above, and below the clouds. These balloons are one of the only safe options for obtaining these kinds of measurements inside of supercooled liquid clouds, which pose an icing threat to aircraft.

Both teams were working under the guidance of the AMF3 site operations to evaluate options for the ARM Facility’s plans to conduct routine UAS and tethered balloon operations at Oliktok to address high priority Arctic science questions.

Arctic Challenges

An Arctic fox explores the area surrounding the AMF3.
An Arctic fox explores the area surrounding the AMF3.

Throughout the campaign, both teams battled rapidly reducing sunlight, heavy winds, thick snow, and instruments or vehicles icing over. Though they didn’t encounter any polar bears, they did see a herd of caribou and were occasionally visited by an arctic fox. While the challenging environment resulted in a limited number of “no-fly” days, the teams took full advantage of the downtime to perform analysis on the data collected and collaborate on improvements to platforms and sampling methods.

One of the largest challenges faced by aircraft of all scales when operating in polar environments is the threat of aircraft icing. Since the de-icing technology deployed on large, passenger aircraft is not yet available for small unmanned aircraft, this threat was constantly evaluated by the CU team. During the middle of the COALA campaign, the team was confronted with consecutive days of icing conditions. In order to evaluate the performance of their aircraft in such conditions, the team conducted limited, controlled flight operations over the open tundra and were happy to find that the DataHawk handled the conditions well. These flights provided helpful information on the icing environment as well as on the operational limits of the deployed platforms.

Despite the many challenges, the teams were satisfied with their efforts and results and look forward to processing their findings. In the spring of 2015, the CIRES team will return to the facility for the Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS) campaign.

Pictures courtesy of Gijs de Boer from his COALA blog. To learn more about the AMF3 deployment in Alaska, visit the NSA web page.

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The ARM Climate Research Facility is a national scientific user facility funded through the U.S. Department of Energy’s Office of Science. The ARM Facility is operated by nine Department of Energy national laboratories.